The Danish National Patient Registry: a review of content, data quality, and research potential

Figures & data

Table 1 Aims of the Danish National Patient Registry

1. Form the basis for the Danish Health and Medicines Authority’s hospital statistics

2. Form the basis for health economic calculations

3. Provide the Danish authorities with data to support hospital planning

4. Provide data to support the authorities responsible for hospital inspection

5. Monitor the frequency of various diseases and treatments

6. Provide a sampling frame for longitudinal population-based and clinical research

7. Facilitate quality assurance of Danish health care services

8. Provide hospital physicians with access to patient’s hospitalization histories

Table 2 Content of the Danish National Patient Registry

Administrative data
CPR number	Unique ten-digit personal identification number assigned at birth or upon emigration
Residence	Municipality and region of residence
Hospital and department	Hospital and department admitting the patient
Patient contact	Inpatient, outpatient (ambulatory), or emergency department contacts
Admission type	Acute or nonacute
Referred from/referred to	General practitioner, outpatient (ambulatory) clinic, other hospital departments, foreign hospital, no referral (eg, acute admission via ambulance), or death (only applies to “referred to” if death is declared during admission)
Referral period	Period from referral date to start date for hospital contact
Waiting time	Period from referral date to start date for treatment
Contact reason	Reason for the hospital contact: diagnosis, accident, act of violence, suicide attempt, late complications, unknown (eg, unconscious patient), or other (rarely used)
Accident	Accident description, when an accident is the contact reason
Time specifications	Date and time of inpatient admission/discharge, start/end date for outpatient treatment, date of arrival to/discharge from emergency department, and date of referral (if relevant)
Other administrative data	Home visit (AAF6) or out-of-home visit (eg, drop-in center or prison service; AAF7) Treatment status of cancers covered by national treatment guaranties: referred, examined, or under treatment
Diagnoses
Primary diagnosis	Main reason for hospitalization. When a patient is being examined and a diagnosis is not yet confirmed, a tentative “obs pro” (observation for) diagnosis may be used (the ICD-10 “Z-codes”)
Secondary diagnoses	Optional diagnoses supplementing the primary diagnosis by, eg, describing the underlying chronic disease that is related to the current patient contact
Referral diagnosis	Diagnosis given by referring unit as the reason for referral
Temporary diagnoses	Diagnoses used only for ongoing nonpsychiatric outpatient contacts and never for completed contacts or for psychiatric contacts
Complications	Procedure-related complications, eg, perioperative bleeding or postoperative infections
Supplementary codes	Up to 50 codes supplementing the primary diagnosis, typically tentative diagnoses (eg, adding meningitis examination to the primary diagnosis disease of the central nervous system), drug abuse (eg, adding heroin to acute opioid intoxication), drug side effects (eg, adding acetylsalicylic acid to peptic ulcer disease), or cancer stage (eg, adding TNM stage to primary tumor diagnosis)
Treatments
Surgery (K)	For example, surgery on the thyroid gland (KBA), lung (KGD), or coronary arteries (KFN)
Other treatments (B)	Patient care: eg, dress a wound with sterile bandage (BNPA40) or supra pubic catheter change (BJAZ14) Invasive procedures: eg, implantation of pacemaker (BFCA0)/cardioverter-defibrillator (BFCB0) or radiofrequency ablation (BFFB) Mechanical ventilation: invasive (BGDA0) or noninvasive (BGDA1) Cancer/immune-modulating treatments: antibody or immune-modulating therapy (BOHJ), radiation therapy (BWG), stem cell or bone marrow transplantation (BOQE and BOQF), cytostatic treatment (BWHA), and biological therapies (BWHB) Other medical treatment: eg, fibrinolysis (BOHA1) or initiation of parturition with prostaglandin (BKHD20) Telemedicine: eg, patient counseling by phone (BVAA33A), email (BVAA33B), or video (BVAA33D) Systemic psychotherapy: individual (BRSP1), couple (BRSP2), or family (BRSP3) Physiotherapy or occupational therapy (BVD) Other treatment examples: dialysis (BJFD), medical abortion (BKHD4), electroconvulsive therapy (BRXA1), total parenteral nutrition (BUAL1), and acupuncture (BAFA80)
Anesthesia and intensive care (N)	For example, during intensive care (NABB)
Examinations
Radiological procedures (U)	For example, angiography (UXA), computed tomography (UXC), magnetic resonance imaging (UXM), X-ray (UXR), and ultrasound scan (UXU)
Temporary examinations (W)	Temporary classification of examinations
Other examinations (ZZ)	For example, planning rehabilitation (ZZ0175X), distortion product otoacoustic emission (ZZ7307), and cardiotocography (ZZ4233) For example, psychological evaluation (ZZ4991), semistructured diagnostic interview (ZZ4992), writing medical certificate (ZZ0182), providing preoperative antibiotic prophylaxis (ZPL0C), and procedure cancellation due to nonappearance of the patient (ZPP30)

Abbreviations: CPR, Civil Personal Register; TNM, Classification of malignant tumours based on tumor size (T), lymph node involvement (N) and distant metastasis (M).

Figure 1 Timeline for the content and classification systems in the Danish National Patient Registry.

Abbreviations: DCECI, Danish Classification of External Causes of Injury; ed, edition; ICD, International Classification of Diseases; NCECI, Nordic Classification of External Causes of Injury; NOMESCO, Nordic Medico-Statistical Committee.

Table 3 Time line for patient contact and admission types in the Danish National Patient Registry

	Code	Registration period
Patient contact type
Inpatient	0	Jan 1, 2002–ongoing
24 hour patient	0	Jan 1, 1977–Dec 31, 2001
Daytime patient	1	Jan 1, 1977–Dec 31, 1986
Half-day patient	1	Jan 1, 1987–2001
Outpatient	2	Jan 1, 1987–ongoing
Overnight patient	2	Jan 1, 1977–Dec 31, 1986
Emergency department patient	3	Jan 1, 1987–Dec 31, 2013
Admission type
Acute	1	Jan 1, 1987–ongoing
Nonacute	2	Jan 1, 1987–ongoing

Table 4 Number of patients registered in the Danish National Patient Registry according to disease categories and patient contacts, 1977–2012a

ICD-8	ICD-10	Disease categories	Inpatient contact, n (%)	Outpatient contact, n (%)	Emergency department contact, n (%)	Any patient contact, n (%)
All	All	All diseases	7,268,857 (100)	5,953,405 (100)	5,097,300 (100)	8,085,603 (100)
0–139	A00–B99	Certain infectious and parasitic diseases	801,471 (11.0)	232,080 (3.9)	104,089 (2.0)	975,286 (12.1)
140–239	C00–D48	Neoplasms	1,308,247 (18.0)	910,226 (15.3)	18,619 (0.4)	1,599,930 (19.8)
280–289	D50–D89	Diseases of the blood and blood-forming organs	351,455 (4.8)	146,420 (2.5)	13,779 (0.3)	416,132 (5.1)
240–279	E00–E90	Endocrine, nutritional, and metabolic diseases	972,238 (13.4)	653,091 (11.0)	69,610 (1.4)	1,232,964 (15.2)
290–319	F00–F99	Mental and behavioral disorders	575,514 (7.9)	218,086 (3.7)	137,711 (2.7)	743,981 (9.2)
320–359	G00–G99	Diseases of the nervous system	514,425 (7.1)	504,543 (8.5)	90,232 (1.8)	840,500 (10.4)
360–379	H00–H59	Diseases of the eye and adnexa	295,631 (4.1)	738,413 (12.4)	126,565 (2.5)	997,947 (12.3)
380–389	H60–H95	Diseases of the ear and mastoid process	271,495 (3.7)	547,612 (9.2)	42,307 (0.8)	750,109 (9.3)
390–459	I00–I99	Diseases of the circulatory system	1,971,447 (27.1)	1,106,198 (18.6)	311,333 (6.1)	2,312,646 (28.6)
460–519	J00–J99	Diseases of the respiratory system	1,738,535 (23.9)	713,021 (12.0)	204,853 (4.0)	2,018,882 (25.0)
520–579	K00–K93	Diseases of the digestive system	1,717,940 (23.6)	1,116,975 (18.8)	174,675 (3.4)	2,229,186 (27.6)
680–709	L00–L99	Diseases of the skin and subcutaneous tissue	421,034 (5.8)	434,280 (7.3)	190,607 (3.7)	824,052 (10.2)
710–739	M00–M99	Musculoskeletal and connective tissue disease	1,178,743 (16.2)	1,747,207 (29.3)	440,731 (8.6)	2,387,728 (29.5)
580–629	N00–N99	Diseases of the genitourinary system	1,527,088 (21.0)	1,132,468 (19.0)	123,847 (2.4)	2,066,692 (25.6)
630–679	O00–O99	Pregnancy, childbirth, and the puerperium	1,287,919 (17.7)	429,432 (7.2)	44,587 (0.9)	1,321,981 (16.3)
760–779	P00–P96	Conditions originating in the perinatal period	468,787 (6.4)	75,901 (1.3)	1,867 (0.0)	490,506 (6.1)
740–759	Q00–Q99	Congenital malformations and deformations	274,586 (3.8)	235,560 (4.0)	4,116 (0.1)	412,386 (5.1)
780–799	R00–R99	Symptoms, signs, and findings not classified elsewhere	1,952,537 (26.9)	1,214,203 (20.4)	655,075 (12.9)	2,784,868 (34.4)
800–999	S00–T98	External causes of injury and poisoning	2,184,899 (30.1)	1,751,282 (29.4)	4,252,799 (83.4)	5,056,701 (62.5)
E00–E99	X01–Y98	External causes of morbidity and mortality	669,066 (9.2)	756 (0.0)	27,230 (0.5)	692,424 (8.6)
Y00–Y99	Z00–Z99	Factors influencing health and contact with health services	4,162,984 (57.3)	4,890,778 (82.2)	1,894,891 (37.2)	6,104,084 (75.5)

Notes:

a The disease categories are ordered according to the ICD-10. Both primary and secondary diagnoses were included. A person (ie, one Civil Personal Register number) can contribute in several diseases categories, but only once in each cell.

Abbreviation: ICD, International Classification of Diseases.

Table 5 The 25 most common ICD-10 diagnoses at the four-digit level in the Danish National Patient Registry, according to patient contact type, 1994–2012a

Inpatient contact		Outpatient contact		Emergency department contact
Diagnosis (ICD-10 code)	n (%)	Diagnosis (ICD-10 code)	n (%)	Diagnosis (ICD-10 code)	n (%)
Any	4,610,123 (100)	Any	4,995,365 (100)	Any	4,792,298 (100)
1. Spontaneous vertex delivery (O800)	466,723 (10.1)	Senile cataract, unspecified (H259)	287,008 (5.7)	Fracture of lower end of radius (S934)	590,608 (12.3)
2. Pneumonia, unspecified (J189)	260,815 (5.7)	Presbycusis (H911)	193,200 (3.9)	Open wound of finger(s) without damage to nail (S610)	554,305 (11.6)
3. Abdominal pain, unspecified (R108)	159,390 (3.5)	Unilateral or unspecified inguinal hernia (K409)	178,811 (3.6)	Contusion of finger(s) without damage to nail (S600)	301,454 (6.3)
4. Angina pectoris, unspecified (I209)	147,605 (3.2)	Meniscus derangement due to tear or injury (M232)	157,750 (3.2)	Contusion of wrist and hand, exclusion fingers (S602)	263,753 (5.5)
5. Acute abdomen (R100)	146,264 (3.2)	Essential hypertension (I109)	132,992 (2.7)	Fracture of lower end of radius (S525)	250,339 (5.2)
6. Atrial fibrillation and flutter (I489)	142,849 (3.1)	Hearing loss, unspecified (H919)	126,037 (2.5)	Contusion of knee (S800)	243,863 (5.1)
7. Concussion (S060)	129,704 (2.8)	Fracture of lower end of radius (S525)	123,682 (2.5)	Open wound of head, part unspecified (S019)	242,506 (5.1)
8. Syncope and collapse (R559)	114,942 (2.5)	Complete or unspecified medical abortion (O049)	121,821 (2.4)	Open wound of scalp (S010)	241,943 (5.0)
9. Stroke, unspecified (I649)	112,366 (2.4)	Angina pectoris, unspecified (I209)	120,765 (2.4)	Contusion of other and unspecified parts of foot (S903)	204,344 (4.3)
10. Gastroenteritis of unspecified origin (A099)	107,339 (2.3)	Tear of meniscus (S832)	117,493 (2.4)	Sprain and strain of finger(s) (S636)	199,784 (4.2)
11. Unilateral or unspecified inguinal hernia (K409)	98,996 (2.1)	Abdominal pain, unspecified (R108)	117,381 (2.3)	Fracture of other finger (S626)	171,706 (3.6)
12. Delivery by emergency cesarean section (O821)	97,505 (2.1)	Varicose veins of lower extremities (I839)	116,957 (2.3)	Contusion of shoulder and upper arm (S400)	169,022 (3.5)
13. Volume depletion (E869)	95,031 (2.1)	Disc disorders with radiculopathy (M511)	113,217 (2.3)	Sprain and strain of unspecified parts of knee (S836)	163,976 (3.4)
14. Fracture of neck of femur (S720)	94,372 (2.0)	Asthma, unspecified (J459)	106,652 (2.1)	Concussion (S060)	162,564 (3.4)
15. Calculus of gallbladder, no cholecystitis (K802)	87,351 (1.9)	Hyperplasia of prostate (N409)	106,459 (2.1)	Injury of conjunctiva and corneal abrasion (S050)	155,675 (3.2)
16. Spontaneous breech delivery (O802)	86,451 (1.9)	Atrial fibrillation and flutter (I489)	105,710 (2.1)	Open wound of eyelid and periocular area (S011)	150,449 (3.1)
17. Acute myocardial infarction, unspecified (I219)	84,800 (1.8)	Unspecified hematuria (R319)	105,548 (2.1)	Contusion of thorax (S202)	149,719 (3.1)
18. Cerebral infarction, unspecified (I639)	84,001 (1.8)	Internal derangement of knee, unspecified (M239)	104,986 (2.1)	Contusion of elbow (S500)	147,950 (3.1)
19. Complete or unspecified medical abortion (O049)	80,284 (1.7)	Carpal tunnel syndrome (G560)	96,247 (1.9)	Contusion of toe(s) without damage to nail (S901)	133,673 (2.8)
20. Heart failure, unspecified (I509)	79,877 (1.7)	Calculus of gallbladder, no cholecystitis (K802)	94,599 (1.9)	Sprain and strain of wrist (S635)	133,174 (2.8)
21. Acute appendicitis, unspecified (K359)	74,769 (1.6)	Impingement syndrome of shoulder (M754)	91,306 (1.8)	Superficial injury of head, part unspecified (S009)	117,495 (2.5)
22. Constipation (K590)	73,162 (1.6)	COPD, unspecified (J449)	89,555 (1.8)	Superficial injury of scalp (S000)	117,118 (2.4)
23. Acute cystitis (N300)	72,768 (1.6)	Other primary gonarthrosis (M171)	89,528 (1.8)	Open wound of other parts of wrist and hand (S618)	116,600 (2.4)
24. Vacuum extractor delivery (O814)	69,842 (1.5)	Pain in limb (M796)	86,225 (1.7)	Foreign body in cornea (T150)	115,715 (2.4)
25. Essential hypertension (I109)	68,799 (1.5)	Low back pain (M545)	85,920 (1.7)	Sprain and strain of cervical spine (S134)	114,419 (2.4)

Notes:

a Both primary and secondary diagnoses are included. Factors influencing health status and contact with health services (Z-codes) are not included.

Abbreviation: ICD, International Classification of Diseases; COPD, chronic obstructive pulmonary disease.

Figure 2 User interface of the Danish Health Care Classification System (SKS browser).

Notes: Available at http://www.medinfo.dk/sks/brows.php. English translation (consecutive line order): administrative data/classifications of treatment and care/classification of diseases/classifications of external causes of injury/International Classification of Functioning (ICF)/classification of surgery/Anatomical Therapeutic Chemical (ATC) classification system/anesthesia, intensive care, prehospital care/classification of examinations/temporary classification of examinations/specifications/supplementary codes/ZZ-procedure codes/ZZK, ZZP, ZZV, and ZPP codes and pseudo procedure codes (cancer, cancelled, discontinued)/classification of hospitals and departments.
Abbreviation: SKS, Sundhedsvæsenets Klassifikations System.

Table 6 Summary results from the Danish Health and Medicines Authority’s evaluation of diagnoses in the Danish National Patient Registry in 1990 according to clinical specialties

Clinical specialty	Positive predictive value of correct primary diagnoses
	Five-digit diagnosis codes		Three-digit diagnosis codes
	Primary diagnosis alone (%)	Primary + two secondary diagnoses (%)	Primary diagnosis alone (%)	Primary + two secondary diagnoses (%)
Medicine	66	72	73	81
Pediatrics	74	80	82	89
General surgery	77	82	84	89
Gynecology/obstetrics	77	88	83	94
Orthopedic surgery	83	85	89	91
Overall	73	80	81	88

Table 7 Use of the Danish National Patient Registry according to study design

Cohort studies	Identifying study cohorts from hospitalized patients, the general population (assessed from registries or in combination with primary data collection), and family cohorts (constructed through linkage to the Danish Civil Registration System)
	Identifying study exposures related to diseases, treatments, examinations, and seasonality
	Identifying disease occurrence in the general population (eg, associated with lifestyle factors identified from health surveys) or family cohorts
	Identifying disease outcome (recurrence or complications) in patients identified from the DNPR itself, clinical registries, or randomized trials
	Identifying health care utilization rates through counting frequency of inpatient/outpatient and planned/unplanned contacts
	Identifying temporal trends in disease incidence and use of treatments and diagnostic procedures
Case–control studies	Identifying cases (and exposure from the DNPR, other registries, health surveys, or primary data collection). Risk-set sampling is possible through linkage to the Danish Civil Registration System
Cross-sectional studies	Identifying patient’s medical history at study entry according to diagnoses (index disease and comorbidities), treatments (in-hospital medical treatment, surgical procedures, anesthesia, and intensive care), and diagnostic procedures
Ecological studies	Identifying variations in health care and outcomes at the population level

Abbreviation: DNPR, Danish National Patient Registry.

Figure 3 Timeline for the initiation of selected Danish registries linkable to the Danish National Patient Registry.

Abbreviations: ADHD, attention deficit hyperactivity disorder; ICD, International Classification of Diseases; GP, general practitioner; COPD, chronic obstructive pulmonary disease.

Table 8 Methodological considerations related to the internal validity of cohort studies conducted with data from the Danish National Patient Registry

Precision	The large nationwide sample permits studies of rare diseases, disease complications, and treatment effects in subgroups of patients
Selection bias	The population-based coverage, within a universal health care system with virtually complete follow-up of all patients owing to the Danish Civil Registration System, reduces the risk of selection biases
Information bias	The risk of misclassification warrants validation of all variables used for research
Confounding	The registrations of diagnoses, treatments, and examinations for all hospital contacts may provide data on potential confounding factors. Seasonality may be controlled in the studies of infectious disease

Figure S1 Flowchart for the systematic review of validation studies.

Notes: The literature search was performed on July 20, 2015 using the following search string in 1) PubMed: “Danish National Patient Registry” OR “Danish National Registry of Patients” OR “Danish National Hospital Register” OR “Danish National Health Registry” OR “Danish National Patient Register” OR “Danish Hospital Discharge Registry” OR “Danish National Hospital Registry” OR “Danish Hospital Registers”; and 2) the Danish Medical Journal: “Landspatientregisteret”.

Table S1 Bibliography of validated administrative data, diagnoses, treatments, and examinations in the Danish National Patient Registry

ICD codesa	Condition	Study period (contact type; diagnosis type)	ICD codes/algorithmb	nc	PPV; NPV; sensitivity; specificityd	Reference standard	Reference
Administrative data
	Acute medical admission	2009 (IN)	Acute	127	PPV =97.6 (93.3–99.2); NPV =90.3 (75.1–96.7); Se =97.6 (93.3–99.2); Sp =90.3 (75.1–96.7)	MR	Vest-Hansen B et al. Clin Epidemiol. 2013^Citation52
	Nonacute medical admission	2009 (IN)	Nonacute	31	PPV =90.3 (75.1–96.7); NPV =97.6 (93.3–99.2); Se =90.3 (75.1–96.7); Sp =97.6 (93.3–99.2)	MR	Vest-Hansen B et al. Clin Epidemiol. 2013^Citation52
Diagnoses
A00–B99: Certain infectious and parasitic diseases
A02	Infections among patients diagnosed with cancer within previous 5 y (excl non-melanoma skin cancer)	2006–2010 (IN; A)	A02.1, A02.2C, A15–A19, A20.3, A22.7, A26.7, A42.7, A28.2B, A31, A32.1, A32.7, A39.0, A40–41, A46, A49.9, A54.8D, A54.8G, A87, B00.3, B01.0, B02.1, B26.1, B35–B49, B05.1, G00–G05, H01.0, H03, H60.0, H60.1–H60.3, H62, I33, I39.8, J12–J18, K12.2, K13.0, K61, L01, L03, L08, M00, M01.1, M01.3, M72.6, M86, N10–N12, N15.1, N15.9, N30, N34, N39.0	266	PPV =98.1 (95.7–99.2) overall, 80.1 (75.0–84.5) for agreement of specific infection type, 79.0 (63.7–88.9) for skin infection, 92.5 (85.3–96.3) for pneumonia, 84.4 (71.2–92.3) for sepsis	MR	Holland-Bill L et al. Ann Epidemiol. 2014^Citation53
A39	Meningococcal disease	1980–1993 (IN; A/Be)	036.09, 036.10, 036.11, 036.12, 036.18, 036.19, 036.89, 036.99	296	PPV =85.8 (81.4–89.3); Se =89.8 (85.7–92.8)	MR (ref for PPV); Notification system for communicable diseases and DNPR (ref for Se)	Sørensen HT et al. Int J Risk Saf Med. 1995^Citation54
A40	Septicemia	1994 (IN; A/Be)	A02.1, A28.2, A40–41, A42.7, A54.8, O08.0, O75.3, O85.9, P36	83	PPV =21.7 (14.2–31.7); Se =4.4 (2.8–6.9)	MR; Bacteremia database	Madsen KM et al. Infect Control Hosp Epidemiol. 1998^Citation25
	Bacteremia	2000–2011 (IN; A/Be)	Definite (A02.1, A28.2B, A32.7, A39.2–4, A40–1, A42.7, A49.9A, B37.7, B49.9A) or possible (predominantly, A01.0, A39.0, A41.9, A46.9, I38.9, P36, P37.5, N10.9, N30.0, N39.0, O08.0U, O08.0V, KTJA40, KTJWC00, KTJL10)	37,740	SeDefinite/possible =64.9 (64.5–65.3) SeDefinite =32.3 (31.9–32.7)	Microbiology results recorded in electronic laboratory information system	Gradel KO et al. Plos One. 2015^Citation55
A41	Gram-negative bacteremia	1994–2012 (IN; A/B)	A41.5, A41.9B (septicemia/sepsis due to other Gram-negative organisms or urosepsis)	100	PPVAll =72.0 (62.5–79.9); PPVA41.5 =85.7 (74.3–92.6); PPVA41.9B =54.6 (40.1–68.3)	Microbiology results recorded in electronic laboratory information system	Søgaard KK et al. Clin Epidemiol. 2014^Citation56
B18.0	HBV in HIV patients	1995–2004 (IN/OUT; A/Be)	B18.0–B18.1	47	PPV =63.8 (49.5–76.0); Se =23.3 (16.8–31.3)	Danish HIV Cohort Study	Obel N et al. BMC Med Res Methodol. 2008^Citation57
B18.2	HCV in HIV patients	1995–2004 (IN/OUT; A/Be)	B18.2	134	PPV =94.0 (88.7–96.9); Se =47.7 (41.8–53.7)	Danish HIV Cohort Study	Obel N et al. BMC Med Res Methodol. 2008^Citation57
B20	HIV	1995–2004 (IN/OUT; A/Be)	B20–B24	n/a (≥2006)	Se =98.7 (98.1–99.1)	Danish HIV Cohort Study	Obel N et al. BMC Med Res Methodol. 2008^Citation57
B21	AIDS	1998–2007 (IN/OUT; A)	B21–B24	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
C00–D48: Neoplasms
C00–C75	Any tumor	1998–2007 (IN/OUT; A)	C00–C75	50	PPV =98.0 (89.4–99.9)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
		1977 (IN; A/B)	140–239 (excl brain tumors and non-melanoma skin cancer)	17,956	PPV =91.7 (91.3–92.1); Se =75.8 (75.2–76.3)	DCR	Osterlind A et al. Ugeskr Laeger. 1985^Citation59
C18	Colorectal cancer	2001–2006 (IN/OUT;e A/Be)	C18–20	24,153	PPV =88.9 (88.5–89.3); Se =93.4 (93.1–93.7)	DCR	Helqvist L et al. Eur J Cancer Care. 2012^Citation60
	Colorectal cancer recurrences	2001–2011 (IN/OUT/ED;e A/Be)	C76–C80, C18.9X, C20.9X, BWHA1–2, BOHJ17, BOHJ19B1 (algorithm combining metastasis and chemotherapy codes in the DNPR with cancer recurrence codes in the PD)	70	PPV =85.7 (75.7–92.1); NPV =99.0 (97.0–100); Se =95.2 (86.9–98.4); Sp =96.6 (93.8–98.1)	Actively followed cohort	Lash TL et al. Int J Cancer. 2014^Citation61
C51–58	Gynecological cancers	1977–1988 (IN; A/Be)	180, 182.0, 183 (among women undergoing gynecological surgery)	614	PPV =89.9 (87.3–92.0); Se =94.7 (92.6–96.2)	MR	Kjaergaard J et al. J Epidemiol Biostat. 2001^Citation62
C53	Cervical cancer	1977–1988 (IN; A/Be)	180 (among women undergoing gynecological surgery)	148	PPV =88.5 (82.4–92.7); Se =94.2 (89.1–97.1)	MR	Kjaergaard J et al. J Epidemiol Biostat. 2001^Citation62
C54–55	Uterus cancer	1977–1988 (IN; A/Be)	182.00–182.09 (among women undergoing gynecological surgery)	261	PPV =90.4 (86.2–93.4); Se =92.9 (89.1–95.5)	MR	Kjaergaard J et al. J Epidemiol Biostat. 2001^Citation62
C56	Ovarian cancer	1977–1988 (IN; A/Be)	183	205	PPV =90.2 (85.4–93.6); Se =97.4 (94.0–98.9)	MR	Kjaergaard J et al. J Epidemiol Biostat. 2001^Citation62
C61	Prostate cancer	1995–2012 (IN/OUT; A/B)	C61	240	PPV =98.3 (95.8–99.4)	MR (histologically-/biopsy-verified)	Drljevic A et al. Clin Epidemiol 2014^Citation63
C64	Urological cancer	2004–2009 (IN/OUT; A/Be)	C64–68, D09.0–D09.1, D30.1–D30.9, D41.1–D41.9	41,129	PPV =86.6 (86.3–86.9); Se =94.9 (94.7–95.2)	DCR	Gammelager H et al. Eur J Cancer Prev 2012^Citation64
C76–80	Metastatic solid tumor	1998–2007 (IN/OUT; A)	C76–C80	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
C79.5	Bone metastases or skeletal-related events in patients with prostate (P) or breast (B) cancer	2000–2005 (n/a; n/a)	C79.5, BWGC1, M80.0, M84.4, M90.7, M43.9, 48.5, M54.5, M54.6, M54.9, G95.2, G95.8, KNAG (+ C61.9/C50)	27 P; 15 B	PPVP =92.6 (76.6–97.9); NPVP =71.2 (60.0–80.4); PPVB =73.3 (48.1–89.1); NPVB =90.6 (82.5–95.2); SeP =54.4 (40.2–67.9); SpP =96.3 (87.5–99.0); SeB =57.9 (36.3–76.9); SpB =95.1 (88.0–98.1)	MR	Jensen AØ et al. Clin Epidemiol. 2009^Citation65
C79.5	Bone metastases in patients with prostate cancer	2005–2010 (IN/OUT;e A/Be)	C61 (from DCR) with prespecified PSA values, antiresorptive therapy, and bone scintigraphy, but without C77–C79	212	PPVPSA >50 μg/L =9.6 (4.7–18.5) and NPVPSA <50 μg/L =98.6 (94.9–99.6) regardless of receipt of antiresorptive therapy or presence of bone scintigraphy	MR	Ehrenstein V et al. Clin Epidemiol. 2015^Citation66
C81.0–96.9	Hematological cancer	1994–1999 (IN;e Ae)	C81.0–C96.9	1,075	PPV =84.5 (82.2–86.5); Se =91.5 (89.6–93.1)	DCR	Nørgaard M et al. Eur J Cancer Prev. 2005^Citation67
C81	Lymphoma	1998–2007 (IN/OUT; A)	C81–C85, C88, C90, C96	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
C81	Hodgkin’s disease	1994–1999 (IN;e Ae)	C81.0–9	77	PPV =71.4 (60.5–80.3); Se =88.7 (78.5–94.4)	DCR	Nørgaard M et al. Eur J Cancer Prev. 2005^Citation67
C82	Non-Hodgkin’s lymphoma or chronic lymphocytic leukemia	1994–1999 (IN;e Ae)	C82.0–85.9, C88.0–9, C91.1, C96.0–9	613	PPV =85.3 (82.3–87.9); Se =88.2 (85.3–90.6)	DCR	Nørgaard M et al. Eur J Cancer Prev. 2005^Citation67
C90	Multiple myeloma and other malignant plasma cell neoplasms	1994–1999 (IN;e Ae)	C90.0–2	158	PPV =82.3 (75.6–87.4); Se =90.9 (85.1–94.6)	DCR	Nørgaard M et al. Eur J Cancer Prev. 2005^Citation67
C91	Leukemia	1998–2007 (IN/OUT; A)	C91–C95	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
C92	Acute myeloid leukemia	1994–1999 (IN;e Ae)	C92.0	108	PPV =67.6 (58.3–75.7); Se =89.0 (80.4–94.1)	DCR	Nørgaard M et al. Eur J Cancer Prev. 2005^Citation67
D25	Uterine fibroma	1977–1988 (IN; A/B)	218.99 (among women undergoing gynecological surgery)	1,430	PPV =92.9 (91.4–94.1); NPV =88.9 (87.8–89.9); Se =77.4 (75.4–79.4); Sp =96.8 (96.2–97.4)	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
D27	Benign ovarian neoplasms	1977–1988 (IN; A/B)	220.99 (among women undergoing gynecological surgery)	743	PPV =78.2 (75.1–81.0); NPV =90.0 (89.1–90.9); Se =58.3 (55.2–61.3); Sp =95.9 (95.2–96.5)	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
D35.3	Craniopharyngioma	1985–2004 (IN/OUT;e A/Be)	194.39, 226.21, 226.29, 253.99; D35.3, D44.4, C75.2	607	PPV =30.5 (27.0–34.3); Se =95.2 (77.3–99.2)	MR (for PPV)/Se with ref to North Jutland County registry and registries of a Danish neuroendocrine center	Nielsen EH et al. J Clin Epidemiol. 2011^Citation69
D47.2	Monoclonal gammopathy	2001–2011 (IN/OUT;e A/Be)	D47.2	327	PPV =82.3 (77.8–86.0); Se =16.8 (14.4–19.6)	MR (for PPV); Se with ref to Regional monoclonal gammopathy database	Gregersen H et al. Clin Epidemiol. 2013^Citation70
D50–D89: Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
D35.0A	Pheochromocytoma	1977–1981 (IN; A/B)	255.29	230	PPV =19.1 (14.6–24.7)	MR	Andersen GS et al. Ugeskr Laeger. 1986^Citation71
D50.0	Anemia caused by bleeding	2000–2009 (IN/OUT; A/Be)	D50.0, D62.6	3,391	PPV =95.4 (94.6–96.0)	LABKA	Zalfani J et al. Clin Epidemiol. 2012^Citation72
D51	Anemia caused by B12 deficiency	2000–2009 (IN/OUT; A/Be)	D51	1,089	PPV =36.8 (34.0–39.7)	LABKA	Ghezala IB et al. Clin Epidemiol. 2012^Citation73
D69	Chronic idiopathic thrombocytopenic purpura	1996–2007 (IN/OUT;e A/Be)	D69 (>1 diagnosis >6 mo)	439	PPV =93.4 (90.7–95.4)	MR	Heden KEK et al. Clin Epidemiol. 2009^Citation74
E00–E90: Endocrine, nutritional and metabolic diseases
E10	Diabetes mellitus	1998–2007 (IN/OUT; A)	E10.0, E10.1, E10.9, E11.0, E11.1, E11.9	50	PPV =96.0 (86.5–98.9)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
		1999–2003 (IN/OUT;e A/Be)	E10–13, H36.0, O24, except O24.4	n/a	PPV =64;f Se =97f	GP verification	Kristensen JK et al. Ugeskr Laeger. 2007^Citation75
		1992–2001 (IN/OUT/ED;e A/Be)	249–250, E10–E11 (and/or a prescription for insulin or an oral antidiabetes drug)	65	PPV =96.9 (89.5–99.2)	MR, LABKA	Thomsen RW et al. Diabetes Care. 2004^Citation76
	Diabetes in women	1977–2006e (IN/OUT;e Ae)	249; E10	40	PPV =95.0 (83.5–98.6)e	MR	Atladottir HO et al. Pediatrics. 2009^Citation77
	Diabetes in children	1996–2002 (A;e A/B)	E10–14 (age ≤15 y)	1,479	PPV =95.9 (94.8–96.8); NPV =100 (100–100);g Se =97.9 (97.1–98.6); Sp =100 (100–100)g	MR; Danish registry for child and adolescent diabetes	Svensson J et al. Ugeskr laeger. 2007^Citation78
	Type 1 diabetes mellitus	1996–2002 (IN;e A/B)	E10–14	1,479	PPV =94.3 (93.0–95.4); NPV =100 (100–100);g Se =98.0 (97.1–98.6); Sp =100 (100–100)g	MR; Danish registry for child and adolescent diabetes	Svensson J et al. Ugeskr laeger. 2007^Citation78
		1987–1993 (IN; A/B)	249	1,722	PPV =96.3 (95.4–97.1); Se =91.0 (89.6–92.2)	MR; PR	Nielsen GL et al. J Med Syst. 1996^Citation79
E10.2	Diabetes mellitus with chronic complications	1998–2007 (IN/OUT; A)	E10.2–E10.8, E11.2–E11.8	50	PPV =82.0 (69.2–90.2)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
E22.0	Acromegaly	1991–2009 (IN/OUT/ED;e A/Be)	253.00, 253.01; E22.0	275	PPV =54.2 (48.3–60.0); PPVDep of endocrinology =66.7 (60.0–72.7)	MR	Dal J et al. Clin Epidemiol. 2014^Citation80
E282	Polycystic ovarian syndrome	1977–1988 (IN; A/B)	256.90 (among women undergoing gynecological surgery)	14	PPV =85.7 (60.1–96.0); NPV =99.9 (99.8–100); Se =70.6 (46.9–86.7); Sp =100 (99.9–100)	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
E26.0	Primary hyperaldosteronism	1977–1981 (IN; A/B)	255.00 (Conn’s syndrome)	85	PPV =22.4 (14.8–32.3)	MR	Lund JO et al. Ugeskr Laeger. 1986^Citation81
E41	Undernutrition	2002–2011 (IN;e A/Be)	E12, E41–44, E46–47, E64, Z03.8F (age ≥15 y)	172	PPVDefinite =11.1 (7.2–16.6) PPVDefinite/probable =70.9 (63.8–77.2)	MR	Rasmussen NH et al. Clin Nutr. 2015^Citation82
E87	Hyponatremia	2006–2011 (IN; A/B)	E87.1, E87.1A, P74.2B	5,850	PPV =92.5 (91.8–93.1); NPV =86.2 (86.2–86.2); Se =1.8 (1.7–1.8); Sp =100 (100–100)g	LABKA	Holland-Bill L et al. BMJ Open. 2014^Citation83
F00–F99: Mental and behavioral disorders
F00	Dementia	1998–2007 (IN/OUT; A)	F00–F03, F05.1, G30	50	PPV =98.0 (89.5–99.7)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
		2003 (IN/OUT; A/B)	F00.0–F00.2, F00.9, G30.0–G30.1, G30.8–G30.9, F01.0–F01.3, F01.8–F01.9, F02.0, F03.9	197	PPV =85.8 (80.2–90.0) overall, 81.0 (69.2–89.1) for Alzheimer dementia, 18.5 (8.2–36.7) for vascular dementia	MR; patient interview	Phung TKT et al. Dement Geriatr Cogn Disord. 2007^Citation84
G00–G99: Diseases of the nervous system
G12.2	Amyotrophic lateral sclerosis	1982–2009 (IN/OUT;e A/Be)	348.0, G12.2 (age >19 y)	173	PPVdefinite =69.9 (62.7–76.3); PPVdefinite/probable =77.5 (70.7–83.1); PPVdefinite/probable/suspected =92.5 (87.6–95.6)	MR	Kioumourtzoglou MA et al. Amyotroph Lateral Scler Frontotemporal Degener. 2015^Citation85
G20	Parkinson’s disease	1996–2006 (IN/OUT; A)	342, G20	1,040	PPV =82.4 (80.0–84.6)	MR	Wermuth L et al. Dan Med J 2012^Citation86
		2002–2006 (IN/OUT;e Ae)	G20 (age ≥35 y)	2,572	PPV =91.5 (90.3–92.5)	PR	Rugbjerg K et al. BMJ. 2008^Citation87
	Parkinson’s disease (women)	1996–2009 (IN/OUT;e Ae)	G20e (neurology wards only)	923	PPV =80.5 (77.8–82.9)	MR	Greene N et al. Eur J Neurol. 2014^Citation88
G35.9	Multiple sclerosis treated at Department of Neurology or MS rehabilitation center	1994–2004 (IN/OUT; A/B)	G35.9	4,185	PPV =95.1 (94.3–95.8);f PPVneurol dep =96.3 (95.7–96.9); Se =92.8 (91.9–93.6);f Seneurol dep =86.9 (85.7–88.0)	Danish Multiple Sclerosis Registry	Mason K et al. Acta Neurol Scand. 2012^Citation89
G40	Epilepsy	1977–2002 (IN/OUT; A/Be)	345, G40–41	188	PPV =81.4 (75.2–86.3)	MR	Christensen J et al. Epilepsy Res. 2007^Citation90
G45	Transient ischemic attack	1998–1999 (IN;e A/Be)	G45	38	PPV =57.9 (42.2–72.2) to 68.4 (52.5–80.9)	MR; DS; CT/MRI; autopsy reports; angiography reports	Krarup LH. Neuroepidemiology. 2007^Citation91
		1994–1999e (IN/OUT/ED; A/Be)	G45	134	PPV =60.5 (52.0–68.3)	MR; DS	Johnsen SP et al. J Clin Epidemiol. 2002^Citation92
G81	Hemiplegia	1998–2007 (IN/OUT; A)	G81, G82	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
H00–H95: Diseases of the eye, adnexa, ear, and mastoid process
H71	Cholesteatoma	1977–2007 (IN; A)	387.09; H71, H95.0, Q16.4A + surgery codes (see these below under KDC)	262	PPV =89.3 (85.0–92.5); Se =89.3 (84.7–92.6)	Surgical records	Djurhuus BD et al. Dan Med Bull. 2010^Citation93
I00–I99: Diseases of the circulatory system
I10.9	Essential hypertension in males	1977–2010 (IN/OUT; A/B)	400–404; I10–I15	524	PPV =88.2 (85.4–90.9)	PR	Schmidt M et al. BMJ Open. 2013^Citation94
	Essential hypertension	1983–1990 (IN; A)	401.99	310	PPV =40 (26–55) to 60 (49–70)f	MR	Nielsen HW et al. Ugeskr Læger. 1996^Citation95
I20.0	Acute coronary syndrome	1993–2003 (IN/OUT/ED; A/Be)	410, 427.27; I20.0, I21, I46	1,558	PPVIN/OUT/ED =65.5 (63.1–67.9); PPVIN =80.1 (77.7–82.3)	MR; DS; blood tests, ECG	Joensen AM et al. J Clin Epidemiol. 2009^Citation96
I20.0	Unstable angina	1993–2003 (IN/OUT/ED; A/Be)	I20.0	444	PPVIN/OUT/ED =27.5 (23.5–31.8); PPVIN =42.0 (36.0–48.0)	MR; DS; blood tests, ECG	Joensen AM et al. J Clin Epidemiol. 2009^Citation96
I21	Acute myocardial infarction	1996–2009 (IN;e A)	I21	148	PPV =100 (97.5–100)	MR	Coloma PM et al. BMJ Open. 2013^Citation97
		1998–2007 (IN/OUT; A)	I21, I22, I23	50	PPV =98.0 (89.5–99.7)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
		1993–2003 (IN/OUT/ED; A/Be)	410; I21	1,072	PPVIN/OUT/ED =81.9 (79.5–84.1); PPVIN; A/B =92.4 (90.4–93.9); PPVIN; A =94.4 (92.6–95.7)	MR; DS; blood tests, ECG	Joensen AM et al. J Clin Epidemiol. 2009^Citation96,Citation98
		1982–1991 (IN; A/B)	410, 427.24, 427.27, 427.91, 427.97	5,022	PPVA =94.3 (93.6–94.9); PPVA+B =93.4 (92.6–94.0); SeA =62.8 (61.7–64.0); SeA+B =69.5 (68.4–70.6)	DANMONICA definite or possible cases incl cardiac arrest	Madsen M et al. J Clin Epidemiol. 2003^Citation99
		1979–1980 (IN; A/B)	410–414	527	PPV =92.4 (89.8–94.4)	DS	Madsen M et al. Ugeskr laeger. 1990^Citation100
I26	PE	1994–2006 (IN/OUT/ED; A/B)	450.99; I26	353	PPVAll =67.4 (62.4–72.1); PPVIN/OUT =82.1 (77.2–86.1); PPVED =29.6 (22.0–38.5); PPVA =87.0 (81.9–90.9)	MR; DS; blood tests; ultrasound; venography; echo; V-P lung scan; CT scan	Severinsen MT et al. J Clin Epidemiol. 2010^Citation101
	PE during pregnancy and postpartum	1980–2001 (IN;e Ae)	450.00–450.99; I26.0–I26.9 + (650–666; O80–84)	22	PPVpreg+postpartum =81.8 (59.7–94.8);f PPVpreg =63.6 (40.7–82.8)f	MR	Larsen TB et al. J Clin Epidemiol. 2005^Citation102
	PE after stroke	2003–2006 (IN; A/B)	I26 (after admission to stroke units and age ≥18 y)	11	PPV =90.9 (62.3–98.4); NPV =97.4 (95.8–98.4); Se =0.0 (0.0–32–4); Sp =100 (99.3–100)	MR	Ingeman A et al. Clin Epidemiol. 2010^Citation103
I46	Cardiac arrest	1993–2003 (IN/OUT/ED; A/Be)	427.27; I46	42	PPVIN/OUT/ED =50.0 (35.5–64.5); PPVIN =53.1 (36.5–69.1)	MR; DS; blood tests, ECG	Joensen AM et al. J Clin Epidemiol. 2009^Citation96
I48	Atrial fibrillation or flutter	1993–2009 (IN/OUT/ED; A/B)	427.93, 427.94; I48	284	PPVAll =92.3 (88.6–94.8); PPVIN/OUT =94.0 (90.5–96.3) (independent of diagnosis type and department specialty); PPVED =64.7 (41.3–82.7)	MR + heart rhythm documentation	Rix TA et al. Scand Cardiovasc J. 2012^Citation104
		1980–2002 (n/a; n/a)	427.93, 427.94; I48	174	PPV =98.9 (95.9–99.7)	MR + heart rhythm documentation	Frost L et al. Am J Med. 2007^Citation105
		1980–2002 (n/a; n/a)	427.93, 427.94; I48	116	PPV =96.6 (91.5–98.7)	MR + heart rhythm documentation	Frost L et al. Arch Intern Med. 2004^Citation106
I48.9A	Atrial flutter	1977–1999 (IN/OUT/ED; A/B)	427.94; I48.9A	108	PPV =50.0 (40.7–59.3)	MR + heart rhythm documentation	Rix TA et al. Scand Cardiovasc J. 2012^Citation104
I50	Heart failure	1998–2007 (IN/OUT; A)	I50, I11.0, I13.0, I13.2	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
	Heart failure at University Hospital cardiac care unit	2005–2007 (IN/OUT; A/B)	I11.0, I13.0, I13.2, I42.0, I42.6–9, I50.0–I50.1, I50.9	758	PPVOverall = 84.0 (81.3–86.5); PPFirst-time events = 77.9 (74.1–81.6)f	MR	Mard S et al. Clin Epidemiol. 2010^Citation107
		1998–1999 (IN; A/B)	I50	156	PPV =80.8 (73.9–86.2); NPV =90.1 (88.9–91.2); Sp =98.9 (98.5–99.2); Se =29.4 (25.3–33.9)	Clinical examination	Kümler T et al. Eur J Heart Fail. 2008^Citation108
I60–I69	Cerebrovascular disease	1998–2007 (IN/OUT; A)	I60–I69, G45–G46	50	PPV =94.0 (83.8–97.9)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
		1998–1999 (IN;e A/Be)	I60–I69, G45	236	PPV =78.4 (72.7–83.2) to 80.1 (74.5–84.7)	MR; DS	Krarup LH et al. Neuroepidemiology. 2007^Citation91
		1994–1999e (IN/OUT/ED; A/Be)	I60–I69.8, G45	565	PPV =68.5 (64.6–72.2)	MR; DS	Johnsen SP et al. J Clin Epidemiol. 2002^Citation92
I60–I64	Stroke	1980–2002 (n/a; A/B)	430–434, 436; I60–I64 following a diagnosis of atrial fibrillation/flutter	164	PPV =97.0 (93.1–98.7)	MR	Frost L et al. Am J Med. 2007^Citation105
		2010 (IN; A)	I61, I63–I64 admitted to neurologic wards	46	PPV =93.5 (82.5–97.8); NPV =71.8 (62.8–79.4); Se =58.1 (46.7–68.7); Sp =96.3 (89.8–98.8)	MR including MRI and CT scan (for PPV). Other neurologic disorders were included to assess Se, Sp, and NPV	Wildenschild K et al. Clin Epidemiol. 2013^Citation109
		1998–1999 (IN;e A/Be)	I60–I64	164	PPV =80.5 (73.8–85.8) to 86.0 (79.8–90.5)	MR; DS	Krarup LH et al. Neuroepidemiology. 2007^Citation91
		1994–1999e (IN/OUT/ED; A/Be)	I60–I64	377	PPV =79.3 (74.9–83.1)	MR; DS	Johnsen SP et al. J Clin Epidemiol. 2002^Citation92
	Stroke complications	2003–2006 (IN; A/B)	J12–J18, N30.0, N30.8, N30.9, N10, L899, R297, EUHE, I82.9A-E, I26, K590 (after admission to stroke units and age ≥18 y)	88	PPV =76.1 (66.3–83.8); NPV =85.1 (83.9–86.1); Se =7.7 (5.8–10.3); Sp =99.5 (99.2–99.7)	MR	Ingeman A et al. Clin Epidemiol. 2010^Citation103
I60	Subarachnoid hemorrhage	1998–1999 (IN;e A/Be)	I61	3	PPV =66.7 (20.8–93.9)	MR; DS	Krarup LH et al. Neuroepidemiology. 2007^Citation91
		1994–1999e (IN/OUT/ED; A/Be)	I61	29	PPV =48.3 (31.4–65.6)	MR; DS	Johnsen SP et al. J Clin Epidemiol. 2002^Citation92
		1977–1995 (IN;e A/Be)	430; I60	191	PPVneurosurgery wards =93 (85–98);f PPVneurology wards =75 (60–87);f PPVnon-specialty wards =47 (36–59)f	MR; DS; autopsy reports	Gaist D et al. BMJ. 2000^Citation110
I6I	Intracerebral hemorrhage	1998–1999 (IN;e A/Be)	I60	23	PPV =73.9 (53.5–87.5)	MR; DS	Krarup LH et al. Neuroepidemiology. 2007^Citation91
		1994–1999e (IN/OUT/ED; A/Be)	I60	35	PPV =65.7 (49.2–79.2)	MR; DS	Johnsen SP et al. J Clin Epidemiol. 2002^Citation92
I63	Ischemic stroke	1998–1999 (IN;e A/Be)	I63	33	PPV =97.0 (84.7–99.5) to 100 (89.6–100)	MR; DS	Krarup LH et al. Neuroepidemiology. 2007^Citation91
		1994–1999e (IN/OUT/ED; A/Be)	I63	113	PPV =87.6 (80.3–92.5)	MR; DS	Johnsen SP et al. J Clin Epidemiol. 2002^Citation92
	Pediatric arterial thrombosis (0–18 y)	1994–2006 (IN/OUT/ED;e A/B)	I63–I64, H34.1–H34.2, I74, N28.0A, N28.0D, I21	472	PPVall =53.6 (49.1–58.1); PPVED =7.3 (2.5–19.4); PPVward =58.0 (53.3–62.6); PPVneonates =75.3 (64.9–83.4)	MR; lab tests; ECG; radiology reports	Tuckuviene R et al. Clin Epidemiol. 2010^Citation111
I64	Unspecified stroke	1998–1999 (IN;e A/Be)	I64	105	PPV =72.4 (63.2–80.0) to 80.0 (71.4–86.5) for unspecified stroke confirmed as being any stroke	MR; DS	Krarup LH et al. Neuroepidemiology. 2007^Citation91
		1994–1999e (IN/OUT/ED; A/Be)	I64	200	PPV =76.0 (69.6–81.4) for unspecified stroke confirmed as being any stroke	MR; DS	Johnsen SP et al. J Clin Epidemiol. 2002^Citation92
I70	Peripheral vascular disease	1998–2007 (IN/OUT; A)	I70–I74, I77	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
I80.0	Superficial thrombophlebitis during pregnancy/d postpartum	1980–2001 (IN;e Ae)	451.01, 451.91; I800 + (650–666; O80–84)	125	PPVpreg+postpartum =89.6 (84.3–95.0);f PPVpreg =88.0 (81.0–82.8)f	MR	Larsen TB et al. J Clin Epidemiol. 2005^Citation102
I80.1–3	DVT	1994–2006 (IN/OUT/ED; A/B)	451.00, 451.08, 451.09, 451.99; I80.1–I80.9	742	PPVAll =54.6 (51.0–58.1); PPVIN/OUT =71.3 (67.4–74.9); PPVED =31.9 (27.1–37.0); PPVA =72.4 (68.2–76.2)	MR; DS; blood tests; ultrasound; venography; echo; V-P lung scan; CT scan	Severinsen MT et al. J Clin Epidemiol. 2010^Citation101
	DVT during pregnancy and postpartum	1980–2001 (IN;e Ae)	451.00, 451.08–451.09, 451.90, 451.92, 451.99; I80.1–I80.9 + (650–666; O80–84)	153	PPVpreg+postpartum =86.3 (79.8–91.3);f PPVpreg =74.5 (66.8–81.2)f	MR	Larsen TB et al. J Clin Epidemiol. 2005^Citation102
	DVT after stroke	2003–2006 (IN; A/B)	I82.9 (after admission to stroke units and age ≥18 y)	8	PPV =87.5 (52.9–97.8); NPV =97.1 (95.4–98.2); Se =16.7 (3.0–56.4); Sp =100 (99.3–100)	MR	Ingeman A et al. Clin Epidemiol. 2010^Citation103
I80.1–3+ I26	VTE	1994–2006 (IN/OUT/ED; A/B)	450.99, 451.00, 451.08, 451.09, 451.99; I26, I80.1–I80.9	1,100	PPVAll =58.5 (55.5–61.3); PPVIN/OUT =75.0 (71.9–77.8); PPVED =31.3 (27.2–35.7); PPVA =77.0 (73.7–80.0)	MR; DS; blood tests; ultrasound; venography; echo; V-P lung scan; CT scan	Severinsen MT et al. J Clin Epidemiol. 2010^Citation101
		2004–2012 (IN/OUT; A/B)	I80.1–3, I26 + AC prescription ≤30 d after	20	PPV =90.0 (69.9–97.2)	MR	Schmidt M et al. J Thromb Haemost. 2014^Citation112
	Pediatric VTE (0–18 y)	1994–2006 (IN/OUT/ED;e A/B)	I67.6, I63.6, G0.8, H34.8, I26, I80.1–I80.9, I81–I82, O22.5A, O87.3, O22.3, O22.8–O22.9, O87A–O87F, O87.1	640	PPVall =53.9 (50.0–57.7); PPVED =7.4 (4.1–13.1); PPVward =66.3 (62.1–70.3); PPVneonates =82.4 (66.5–91.7)	MR	Tuckuviene R et al. Clin Epidemiol. 2010^Citation111
	VTE in non-pregnant women 15–49 y	2001–2009 (IN/OUT;e A/Be)	438, 450, 451.00, 451.08, 451.99, 453.02; I26, I67.6, I80.1–I80.3,I82.2–I82.3, I82.8–I82.9	200	PPV =76.0 (69.6–81.4); PPV+AC =99f	MR; ultrasound; phlebography; CT; scintigraphy	Lidegaard O et al. BMJ. 2011^Citation113
	VTE during pregnancy and postpartum	1980–2001 (IN;e Ae)	450.00–450.99, 451.00–451.99; I26.0–I26.9, I80.0–I80.9 + (650–666, O80–84)	304	PPVpreg+postpartum =87.3 (83.0–90.9);f PPVpreg =79.3 (74.3–83.8)f	MR	Larsen TB et al. J Clin Epidemiol. 2005^Citation102
	VTE recurrence	2004–2012 (IN/OUT; A/B)	I80.1–3, I26 (>3 mo after first–time diagnosis) + ultrasound/CT scan during admission or AC prescription ≤30 d after	90	PPVIN/OUT, A/B, scan =27.5 (16.1–42.8); PPVIN/OUT, A/B, AC use =30.2 (18.6–45.1); PPVIN, A/B, scan =79.0 (56.7–91.5); PPVIN, A/B, AC use =56.5 (36.8–74.4)	MR	Schmidt M et al. J Thromb Haemost. 2014^Citation112
	VTE in prostate cancer patients	1995–2012 (IN/OUT; A/B)	I26, I80.1–3 (+ C61)	115	PPV =86.1 (78.6–91.3); NPV =98.3 (94.0–99.5); Se =98.0 (93.1–99.5); Sp =87.8 (81.1–92.3)	MR; VTE diagnostics	Drljevic A et al. Clin Epidemiol 2014^Citation63
J00–J99: Diseases of the respiratory system
J12	Respiratory syncytial virus infections	1996–2003 (IN; A/B)	J12.1, J20.5, J21.0, B97.4	10,983	PPV =92.1 (91.5–92.6); NPV =83.8 (83.4–94.2); Se =67.9 (67.1–68.6); Sp =96.6 (96.4–96.8)	MR; RSV Laboratory database	Stensballe LG et al. Scand J Infect Dis. 2005^Citation114
J12	Pneumonia after stroke	2003–2006 (IN; A/B)	J12–J18 after (admission to stroke unit and age ≥18 y)	14	PPV =92.9 (68.5–98.7); NPV =63.3 (59.3–67.1); Se =6.0 (3.5–10.1); Sp =99.7 (98.5–100)	MR	Ingeman A et al. Clin Epidemiol. 2010^Citation103
J40	Chronic pulmonary disease	1998–2007 (IN/OUT; A)	J40–J47, J60–J67, J68.4, J70.1, J70.3, J84.1, J92.0, J96.1, J98.2, J98.3	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
J44	COPD exacerbation	2008 (IN; A/B)	J44A, J96A, J13A–J18A + J44B (age ≥30 y)	1,581	PPV =92.1 (90.7–93.3); NPVCOPD for related respiratory conditions =80.6 (78.5–82.5)	MR; 1,546 acute hospitalizations for J96 or J13–18 without J44 as B-diagnosis used to obtain NPV	Thomsen RW et al. Respir Med. 2011^Citation115
J45	Asthma history reported by male conscripts	1977–2003 (IN/OUT/ED; A/Be)	493; J45	925	PPV =65.3 (62.2–68.3); NPV =96.5 (96.2–96.7); Se =44.5 (41.9–47.1); Sp =98.5 (98.3–98.6)	Conscription database	Jensen AO et al. Clin Epidemiol. 2010^Citation116
J45	Asthma in children	2002 (IN; A)	J45, J46.9 (age 6–14 y)	319	PPV =84.6 (80.3–88.2); NPV =99.4 (99.1–99.6); Se =90.0 (86.1–92.9); Sp =99.4 (99.1–99.6)	MR; All acute admissions were assessed to yield Se, Sp, and NPV	Moth G et al. Acta Paediatr. 2007^Citation117
J86.0	Pleural empyema	1995–2009 (IN; A/B)	510; J86.0, J86.9	224	PPV =90.6 (86.1–93.8)	MR; lab tests; radiology reports	Søgaard M et al. Clin Epidemiol 2011^Citation118
K00–K93: Diseases of the digestive system
K25	Ulcer disease	1998–2007 (IN/OUT; A)	K22.1, K25–K28	50	PPV =98.0 (89.5–99.7)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
		1997–2001 n/a; n/a)	531–534, K25–K28	200	PPVOverall =84.5 (78.8–88.7); PPVbleeding ulcer =93.0 (84.6–97.0); PPVuncomplicated ulcer =72.7 (64.4–79.6)	MR	Lassen A et al. Am J Gastroenterol. 2006^Citation119
K50	Crohn’s disease	1988–1992 (IN; A/Be)	563.01	281	PPV =97.2 (94.5–98.6); Se =94.4 (89.4–97.1)	MR and PD for PPV; PD for Se	Fonager K et al. Scand J Gastroenterol. 1996^Citation120
K51	Ulcerative colitis	1988–1992 (IN; A/Be)	563.19, 569.04	506	PPV =90.3 (87.4–92.6); Se =93.7 (90.2–96.0)	MR and PD for PPV; PD for Se	Fonager K et al. Scand J Gastroenterol. 1996^Citation120
K59.0	Constipation after stroke	2003–2006 (IN; A/B)	K59.0 (after admission to stroke units and age ≥18 y)	7	PPV =42.9 (15.8–75.0); NPV =84.7 (81.6–87.4); Se =3.9 (1.3–10.8); Sp =99.4 (98.2–99.8)	MR	Ingeman A et al. Clin Epidemiol. 2010^Citation103
K70	Mild liver disease	1998–2007 (IN/OUT; A)	B18, K70.0–K70.3, K70.9, K71, K73–K74, K76.0	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
K70	Liver cirrhosis	1985–1989 (IN; A/Be)	571.09, 571.90–571.92, 571.99	198	PPV =85.4 (79.8–89.6); Se =93.2 (85.9–96.8)	MR and PD for PPV; PD for Se only	Vestberg K. J Med Syst. 1997^Citation121
K70.3	Alcoholic cirrhosis	1997–2005 (IN/OUT/ED;e A/B)e	571.09; K70.3 (+ a liver biopsy during that hospital contact: SNOMED codes T56xxx)	516	PPV =77.7 (73.9–81.1)	PD	Jepsen P et al. BMC Gastroenterol. 2008^Citation122
K72	Moderate/severe liver disease	1998–2007 (IN/OUT; A)	B15.0, B16.0, B16.2, B19.0, K70.4, K72, K76.6, I85	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
K572–K579	Diverticular disease	1999–2008 (IN/OUT; A/Be)	K572–K579	100	PPV =98.0 (93.0–99.5)	Discharge summary/outpatient notes	Erichsen R et al. Clin Exp Gastroenterol. 2010^Citation123
K859	Acute pancreatitis	1981–2000 (IN;e A/Be)	577.00–577.09; K85.9	99	PPV1981–2000 =82 (72.8–88.9)f PPV1997–1999 =91 (83.0–96.0)f	MR	Floyd A et al. Scand J Gastroenterol. 2002^Citation124
L00–L99: Diseases of the skin and subcutaneous tissue
L89.9	Decubitus after stroke	2003–2006 (IN; A/B)	L89.9 (after admission to stroke units and age ≥18 y)	8	PPV =50.0 (21.5–78.5); NPV =96.6 (94.7–97.8); Se =18.2 (5.1–47–7); Sp =99.5 (98.4–99.8)	MR	Ingeman A et al. Clin Epidemiol. 2010^Citation103
M00–M99: Diseases of the musculoskeletal system and connective tissue
M00	Septic arthritis after knee arthroscopy	1998–2000 or 2003–2005 (IN; n/a)	M00, T81.4, T81.8–T81.9 (+ KNGA, KNGD, KNGE, KNGF, or KNGH)	450	Se =66.9 (59.2–73.8)	Danish Patient Insurance Association	Majholm B et al. Dan Med J. 2012^Citation125
M05	Rheumatoid arthritis (women)	1977–2006e (IN/OUT;e Ae)	712.19, 712.39, 712.59; M05, M06	40	PPV =75.0 (59.8–85.8)e	MR	Atladottir HO et al. Pediatrics. 2009^Citation77
	Rheumatoid arthritis	1977–2001 (IN/OUT; A/B)	712.19, 712.39, 712.59; M05–M06 (except M06.1) (age >15 y)	217	PPV =59.0 (52.3–65.3), higher for rheumatology departments and inpatient admissions; Se =26.4 (17.6–37.6)	PPV using MR/Se using MR-confirmed self-reported cases in the Danish Nationwide Twin Population cohort	Pedersen M et al. Eur J Epidemiol 2004^Citation126
M05	Connective tissue disease	1998–2007 (IN/OUT; A)	M05–M06, M08–M09, M30–M36, D86	50	PPV =98.0 (89.5–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
	Connective tissue disease following breast implant	1977–1993 (IN; A/B)	712.09–712.39, 712.59, 716.09, 716.19, 734.00–734.09, 734.19, 734.90	35	PPVDefinite =82.9 (67.3–91.9)	MR	Friis S et al. Ann Plast Surg. 1997^Citation127
M510	Lumbar disc prolapse	1990–1991 (IN; A)	725.11	98	PPV =90f	MR	Jensen MV et al. Ugeskr laeger. 1995^Citation128
M87	Osteonecrosis of the jaw in postmenopausal osteoporosis	2005–2010 (IN/OUT;e A/Be)	K04.6, K10.2, K10.3, M87	60	PPV =31.7 (21.3–44.2)	MR	Gammelager H et al. Clin Epidemiol. 2013^Citation129
	Osteonecrosis of the jaw among cancer patients	2005–2009 (IN/OUT;e A/Be)	K04.6, K10.2–K10.3 (except K10.2E–F), M87 + prior C00–C97 (except C44)	91	PPV =19.8 (12.9–29.1)	MR	Gammelager H et al. Cancer Epidemiol. 2012^Citation130
	Osteonecrosis of the jaw in patients with cancer diagnosed within 5 y	2005–2010e (IN/OUT;e A/Be)	K04.6, K10.2, K10.3, M87 + prior C15–C29, C33–C43, C45–C97 (excl head and neck cancers and non-melanoma skin cancer) + departments of oral and maxillofacial surgeries	197	PPV =42.1 (35.5–49.1); Se =73.3	MR	Ehrenstein V et al. Pharmacoepidemiol Drug Saf. 2014^Citation131
N00–N99: Diseases of the genitourinary system
N00	Moderate to severe renal Disease	1998–2007 (IN/OUT; A)	I12, I13, N00–N05, N07, N11, N14, N17–N19, Q61	50	PPV =100 (92.9–100)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
N30.0	Urinary infection after stroke	2003–2006 (IN; A/B)	N30.0, N30.8, N30.9, N10 (after admission to stroke units and age ≥18 y)	39	PPV =76.9 (61.7–87.4); NPV =70.9 (67.0–74.6); Se =14.3 (9.8–20.4); Sp =98.0 (96.1–99.0)	MR	Ingeman A et al. Clin Epidemiol. 2010^Citation103
N80	Endometriosis	1977–1988 (IN; A/B)	625.3 (among women undergoing gynecological surgery)	427	PPV =95.1 (92.6–96.8); NPV =89.3 (88.4–90.2); Se =45.8 (42.6–49.1); Sp =99.5 (99.2–99.7)	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
N830–N832	Ovarian cysts	1977–1988 (IN; A/B)	615.2	601	PPV =75.5 (72.0–78.8); NPV =87.2 (86.2–88.2); Se =45.1 (42.1–48.2); Sp =96.2 (95.6–96.8)	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
N91–N94	Bleeding disorders	1977–1988 (IN; A/B)	626 (among women undergoing gynecological surgery)	986	PPV =93.9 (92.3–95.2); NPV =95.2 (94.5–95.8); Se =83.0 (80.7–85.1); Sp =98.4 (98.0–98.8)	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
O00–O99: Pregnancy, childbirth and puerperium
O021–03	Abortion	1984 (IN; A/Be)	642, 644, and 631, 643, 645 if also registered in Register of Legally	359	PPV =46–69 for confirmation on four-digit level	DS	Schmidt L et al. Ugeskr laeger. 1989^Citation132
	Spontaneous abortion	1980–2008 (IN/OUT/ED;e Ae)	634.6, 645.1, 643.8, 643.9; O02.1A, O03	117	PPVAll =97.4 (92.7–99.1)	DS	Lohse SR et al. Clin Epidemiol. 2010^Citation133
O04–06	Provoked abortion	1994 (IN;e A/Be)	O04–06	17,764	PPV =93.5 (93.2–93.9); Se =97.0 (96.8–97.3)	Register of Legally Induced Abortions	Krebs L et al. Ugeskr laeger. 1997^Citation32
O139	Gestational hypertension	1998–2000 (IN/OUT; A/Be)	O13.9	3,039	PPV =56.3 (33.2–76.9); NPV =97.3 (96.7–97.8); Se =10.0 (5.4–17.9); Sp =99.8 (99.5–99.9)	MR	Klemmensen ÅK et al. Am J Epidemiol. 2007^Citation134
O139	Hypertensive disorders of pregnancy	1998–2000 (IN/OUT; A/Be)	O13.9–O14.1–O14.2, O14.9–O15.0	3,039	PPV =88.8 (81.0–93.6); NPV =96.9 (96.2–97.5); Se =48.9 (41.6–56.2); Sp =99.6 (99.3–99.8)	MR	Klemmensen ÅK et al. Am J Epidemiol. 2007^Citation134
		1982–1987 (IN; A/Be)	n/a	112	PPV =70;f NPV =98;f Se =75f	MR	Kristensen J et al. J Clin Epidemiol 1996^Citation135
O14	Preeclampsia	1998–2000 (IN/OUT; A/Be)	O14.0–O14.2, O14.9–O15.0	3,039	PPV =74.4 (64.0–82.6); NPV =99.1 (98.7–99.4); Se =69.3 (59.0–78.0); Sp =99.3 (98.9–99.5)	MR	Klemmensen ÅK et al. Am J Epidemiol. 2007^Citation134
		2001 (IN; A/Be)	O13–14	39	PPV =69.2 (53.6–81.4); NPV =98.6 (97.7–99.2); Se =64.3 (49.2–77.0); Sp =98.9 (98.1–99.4)	MR	Langhoff-Ross J et al. 2003^Citation136
O24	Gestational diabetes	2001 (IN; A/Be)	O24	21	PPV =100 (84.5–100); NPV =99.7 (99.2–99.9); Se =87.5 (69.0–95.7); Sp =100 (99.7–100)	MR	Langhoff-Ross J et al. 2003^Citation136
O32	Malpresentation of fetus	2001 (IN; A/Be)	O32	37	PPV =48.7 (33.5–64.1); NPV =99.3 (98.6–99.6); Se =69.2 (50.0–83.5); Sp =98.3 (97.3–98.9)	MR	Langhoff-Ross J et al. 2003^Citation136
O342	Previous cesarean section	2001 (IN; A/Be)	O34.2, Z35.8E	84	PPV =90.5 (82.3–95.1); NPV =97.7 (96.6–98.5); Se =76.0 (66.8–83.3); Sp =99.2 (98.5–99.6)	MR	Langhoff-Ross J et al. 2003^Citation136
O365	Small for gestational age	2001 (IN; A/Be)	O36.5	25	PPV =56.0 (37.1–73.3); NPV =99.5 (98.8–99.8); Se =70.0 (48.1–85.5); Sp =99.0 (98.2–99.4)	MR	Langhoff-Ross J et al. 2003^Citation136
O409	Polyhydramnios	1982–1987 (IN; A/Be)	n/a	19	PPV =74;f NPV =100;f Se =82f	MR	Kristensen J et al. J Clin Epidemiol 1996^Citation135
O42	Premature rupture of membranes	2001 (IN; A/Be)	O42.3	50	PPV =64.0 (50.1–75.9); NPV =98.5 (97.6–99.1); Se =66.7 (52.5–78.3); Sp =98.3 (97.4–98.9)	MR	Langhoff-Ross J et al. 2003^Citation136
O44	Placenta previa	1982–1987 (IN; A/Be)	n/a	53	PPV =70;f NPV =99;f Se =68f	MR	Kristensen J et al. J Clin Epidemiol 1996^Citation135
O45	Abruptio placenta	1982–1987 (IN; A/Be)	n/a	172	PPV =69;f NPV =97;f Se =70f	MR	Kristensen J et al. J Clin Epidemiol 1996^Citation135
O489	Prolonged pregnancy	2001 (IN; A/Be)	O48.9	53	PPV =67.9 (54.5–78.9); NPV =99.4 (98.7–99.7); Se =83.7 (70.0–91.9); Sp =98.4 (97.5–99.0)	MR	Langhoff-Ross J et al. 2003^Citation136
O62	Abnormalities of forces of labor	2001 (IN; A/Be)	O62.2	317	PPV =85.5 (81.2–88.9); NPV =88.2 (85.7–90.2); Se =73.8 (69.1–78.1); Sp =94.0 (92.0–95.4)	MR	Langhoff-Ross J et al. 2003^Citation136
O641	Obstructed labor due to breech presentation	2001 (IN; A/Be)	O64.1, O32	46	PPV =76.1 (62.1–86.1); NPV =99.4 (98.7–99.7); Se =83.3 (69.4–91.7); Sp =99.0 (98.2–99.4)	MR	Langhoff-Ross J et al. 2003^Citation136
O654	Obstructed labor due to fetopelvic disproportion	2001 (IN; A/Be)	O65.4	21	PPV =85.7 (65.4–95.0); NPV =98.6 (97.8–99.2); Se =54.6 (38.0–70.2); Sp =99.7 (99.2–99.9)	MR	Langhoff-Ross J et al. 2003^Citation136
O68	Fetal distress	2001 (IN; A/Be)	O68	166	PPV =63.3 (55.7–70.2); NPV =97.4 (96.2–98.2); Se =80.8 (73.2–86.6); Sp =93.9 (92.2–95.2)	MR	Langhoff-Ross J et al. 2003^Citation136
O700	First degree perineal laceration	2001 (IN; A/Be)	O70.0	174	PPV =50.6 (43.2–57.9); NPV =90.5 (88.4–92.2); Se =49.2 (41.9–56.4); Sp =90.9 (88.9–92.6)	MR	Langhoff-Ross J et al. 2003^Citation136
O701	Second degree perineal laceration	2001 (IN; A/Be)	O70.1	91	PPV =46.2 (36.3–56.3); NPV =96.3 (95.0–97.3); Se =52.5 (41.7–63.1); Sp =95.3 (93.9–96.4)	MR	Langhoff-Ross J et al. 2003^Citation136
O710	Rupture of uterus	1980–1987 (IN; A/Be)	O71.0–O71.1	956	PPV =13.5 (11.5–15.8)	MR	Devantier A et al. Ugeskr Læger 1991^Citation137
O714	Vaginal laceration	2001 (IN; A/Be)	O71.4	56	PPV =8.9 (3.9–19.3); NPV =99.7 (99.2–99.9); Se =62.5 (30.6–86.3); Sp =95.4 (94.1–96.5)	MR	Langhoff-Ross J et al. 2003^Citation136
O72	Postpartum hemorrhage	2001 (IN; A/Be)	O72	57	PPV =52.6 (39.9–65.0); NPV =98.6 (97.7–99.2); Se =66.7 (52.1–78.6); Sp =97.5 (96.4–98.3)	MR	Langhoff-Ross J et al. 2003^Citation136
P00–P96: Certain conditions originating in the perinatal period
P22	Infant respiratory distress syndrome	1977–2008 (IN;e A/Be)	776.19; P22.0	90	PPVOverall =81.1 (71.8–87.9); PPVpreterm infants born <37 wks =89.2 (79.4–94.7) for	MR	Thygesen SK et al. Clin Epidemiol. 2013^Citation138
P57.0	Kernicterus	1994–2003 (IN; A/Be)	P57.0, P57.7, P57.9 (+ gestational age ≥35 y)	15	PPV =40.0 (19.8–64.3)	MR	Maimburg RD et al. Acta Obstet Gynecol Scand. 2009^Citation139
Q00–Q99: Congenital malformations, deformations and chromosomal abnormalities
Q20	Congenital cardiac malformations	2000–2008 (IN/OUT/ED;e A/Be)	Q20–25, except Q20.9, Q21.9, Q22.9, Q23.9, Q24.9, Q25.9	3,536	PPV =98.4 (98.0–99.8)	MR	Agergaard P et al. Clin Epidemiol. 2011^Citation140
		1994–2002 (IN/OUT;e A/Be)	Q20–26	418	PPV =89.0 (85.6–91.7)	MR; echo, autopsy	Jepsen B et al. Int J Risk Saf Med. 2006^Citation141
		1991–1994 (IN; A/Be)	740–759; Q00–99 (except 755.69, 752.10–752.19, Q53, Q65)	744	PPV =88.2 (85.7–90.3); Se =89.9 (87.5–91.9)	MR; Medical Birth Registry; National Registry of Congenital Abnormalities	Larsen H et al. Scand J Public Health. 2003^Citation142
Q53	Cryptorchidism	1995–2009 (n/a; A)	Q53	452	PPV =80.3 (76.4–83.7)	MR	Jensen MS et al. J Urol. 2012^Citation143
Q54	Hypospadias	1989–2003 (IN;e A/Be)	752.20–752.29; Q54	43	PPV =93.0 (81.4–97.6)	MR	Pedersen L et al. Int J Med Sci. 2006^Citation144
Q96	Turner syndrome	1984–1993 (IN; A/B)	310.54, 311.54, 312.54, 313.54, 314.54, 315.54, 759.50e	237	PPV =68.8 (62.6–74.3)	MR; Cytogenetic Central Register	Gravholt CH et al. J Clin Epidemiol. 1998^Citation145
R00–R99: Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
R29.7	Falls after stroke	2003–2006 (IN; A/B)	R29.7, EUHE (after admission to stroke units and age ≥18 y)	1	PPV =0.0 (0.0–79.4); NPV =84.5 (81.4–87.2); Se =0 (0–5.1); Sp =99.8 (98.9–100)	MR	Ingeman A et al. Clin Epidemiol. 2010^Citation103
R56	Febrile seizures	1990–2001 (IN/OUT; A/Be)	780.21; R56.0	249	PPV =92.8 (88.8–95.4); NPV =98.6 (98.2–98.8); Se =71.5 (66.4–76.2); Sp =99.7 (99.6–99.8)	MR/telephone interviews	Vestergaard M et al. J Clin Epidemiol. 2006^Citation146
R570	Shock overall	2005–2012 (IN; A/B)	R57.0–R57.2, A41.9A (+BFHC92, BFHC93 excl BFHC93E-H, BFHC95)	158	PPV =86.1 (79.8–90.6); PPV+ Inotrope/vasopressor =93.1 (84.8–97.0)	MR	Lauridsen MD et al. BMC Med Res Methodol. 2015^Citation147
R570	Cardiogenic shock	2005–2012 (IN; A/B)	R570 (+ BFHC92, BFHC93 excl BFHC93E-H, BFHC95)	46	PPV =93.5 (82.5–97.8); PPV+ Inotrope/vasopressor =96.0 (80.5–99.3)	MR	Lauridsen MD et al. BMC Med Res Methodol. 2015^Citation147
R571	Hypovolemic shock	2005–2012 (IN; A/B)	R571 (+ BFHC92, BFHC93 excl BFHC93E-H, BFHC95)	34	PPV =70.6 (53.8–83.2); PPV+ Inotrope/vasopressor =69.2 (42.4–87.3)	MR	Lauridsen MD et al. BMC Med Res Methodol. 2015^Citation147
R572	Septic shock	2005–2012 (IN; A/B)	R572, A41.9A (+ BFHC92, BFHC93 excl BFHC93E-H, BFHC95)	78	PPV =69.2 (58.3–78.4); PPV+ Inotrope/vasopressor =82.4 (66.5–91.7)	MR	Lauridsen MD et al. BMC Med Res Methodol. 2015^Citation147
S00–T98: Injury, poisoning and certain other consequences of external causes
S02	Head injury	1982–1985e (IN; n/a)e	800–803, 850–854e	<50e	PPV =90f	MR	Sørensen HT et al. Ugeskr Laeger. 1987^Citation148
S73	Traumatic hip dislocation	1989–1990 (IN; n/a)	835.99	755	PPV =16.0 (13.6–18.8)	MR; X-rays	Hougaard K et al. Ugeskr Laeger 1992^Citation149
T634F	Anaphylactic shock after bee sting	1973–1985 (IN; A/Be)	999.49	n/a	Se =60.0 (38.7–78.1)	MR	Sørensen HT et al. Allergy. 1989^Citation150
T84.5	Periprosthetic hip joint infection	2003–2008 (IN; A/Be)	T84.5 + hip-specific NCSP code + departments of orthopedic surgery. Infection-specific surgery: KNFS19, KNFS49, KNFU89, KNFW69	283	PPV =84.8 (80.2–88.5); PPV+ Infection-specific surgical code =86.1 (80.5–90.3)	MR	Lange J et al. Hip Int. 2015^Citation151
Z00–Z99: factors influencing health status and contact with health services
Z131	Glucose tolerance test	2001 (IN; A/Be)	Z13.1	111	PPV =57.7 (48.4–66.4); NPV =94.8 (93.2–96.0); Se =54.7 (45.7–63.4); Sp =95.4 (93.9–96.5)	MR	Langhoff-Ross et al. 2003^Citation136
Z358D	High-risk pregnancy due to previous complicated pregnancy/birth	2001 (IN; A/Be)	Z35.8D	29	PPV =34.5 (19.9–52.7); NPV =97.5 (96.5–98.3); Se =27.0 (15.4–43.0); Sp =98.3 (97.3–98.9)	MR	Langhoff-Ross et al. 2003^Citation136
Z358E	High-risk pregnancy due to previous cesarean section	2001 (IN; A/Be)	Z35.8E	77	PPV =88.3 (79.3–93.7); NPV =97.3 (96.1–98.1); Se =70.1 (60.4–78.3); Sp =99.1 (98.4–99.5)	MR	Langhoff-Ross et al. 2003^Citation136
Other conditions
	Charlson Comorbidity Index conditions	1998–2007 (IN/OUT; A)	See individual diseases	950	PPV =98.0 (96.9–98.7)	DS	Thygesen SK et al. BMC Med Res Methodol. 2011^Citation58
Treatments
Surgery (K)
KDC	Surgery for cholesteatoma	1977–2007 (IN)	20380–20700, 20990, KDC, KDD, KDE, KDFD30 (except KDCA10, KDCA20, KDCW00, KDEE, KDEE00)	107	PPV =98.1 (93.4–95.5)	Surgical records	Djurhuus et al. Dan Med Bull. 2010^Citation93
KHAD10	Breast implant	1977–1992 (IN)	38500, 38540	2,576	PPV =100 (99.9–100)g	MR	Friis S et al. Ann Plast Surg. 1997^Citation127
		1977–1989 (IN; n/a)	3854	71	PPV =100 (94.9–100)g	MR	McLaughlin JK et al. J Natl Cancer Inst. 1995^Citation152
KHAD00	Breast augmentation	1977–1989 (IN; n/a)	3850	74	PPV =94.6 (86.9–97.9)	MR	McLaughlin JK et al. J Natl Cancer Inst. 1995^Citation152
KJAP	Intraperitoneal adhesiolysis	1977–1988 (IN)	40480	341	PPV =95.9 (93.2–97.5); NPV =99;f Se =87.0 (83.2–90.0); Sp =100f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KJBC00	Gastroesophageal antireflux operation	1997–1999 (IN)	KJBC00, KJBC01 (age ≥18 y + admission >3 days or readmission or in-hospital death)	243	PPV =100 (98.4–100)	MR	Holte K et al. Ugeskr Laeger. 2001^Citation153
KJEA	Appendectomy	1977–1988 (IN)	43000	899	PPV =99.0 (98.1–99.5); NPV =100;f Se =98.5 (97.4–99.1); Sp =100f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KJKA2	Cholecystectomy	2004–2005 (IN)	KJKA2	1,361	PPV =99.9 (99.6–100)	MR	Harboe KM et al. Int J Qual Health Care. 2009^Citation154
KKFC10	Orchiectomy in prostate cancer patients	2002–2008 (IN)	KKFC10, KKFC13, KKFC15	50	PPV =100 (92.9–100); NPV =100 (92.9–100)	MR	Jespersen CG et al. Clin Epidemiol. 2012^Citation155
KKFH00	Corrective surgery of cryptorchidism	1995–2009 (IN)	KKFH00–KKFH01, KKFH10	249	PPV =99.2 (97.1–99.8)	MR	Jensen MS et al. J Urol. 2012^Citation143
KL	Operations for gynecological cancer	1977–1988 (IN)	Hysterectomy, oophorectomy, partial resection of the ovaries (unspecified codes)	n/a (≈10,182)	PPV =95f	MR	Kjaergaard J et al. J Epidemiol Biostat. 2001^Citation62
KLAD00A	Unilateral ovarian resection	1977–1988 (IN)	60040	1,128	PPV =96.2 (94.9–97.2); NPV =98;f Se =93.3 (91.7–94.6); Sp =99f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KLAD00B	Bilateral ovarian resection	1977–1988 (IN)	60060	195	PPV =82.1 (76.1–86.8); NPV =100;f Se =91.4 (86.3–94.7); Sp =99f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KLAE1	Unilateral oophorectomy	1977–1988 (IN)	60100	399	PPV =90.5 (87.2–93.0); NPV =99;f Se =93.5 (90.6–95.6); Sp =99f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KLAE2	Bilateral oophorectomy	1977–1988 (IN)	60120	87	PPV =79.3 (69.7–86.5); NPV =100;f Se =79.3 (69.7–86.5); Sp =100f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KLAF0	Unilateral salpingo-oophorectomy	1977–1988 (IN)	60320	925	PPV =95.8 (94.3–96.9); NPV =98;f Se =90.4 (88.4–92.1); Sp =99f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KLAF1	Bilateral salpingo-oophorectomy	1977–1988 (IN)	60300	534	PPV =85.6 (82.4–88.3); NPV =99;f Se =89.6 (86.7–92.0); Sp =98f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KLCD	Hysterectomy	1977–1988 (IN)	61020	3,162	PPV =99.1 (98.7–99.4); NPV =96;f Se =97.9 (97.3–98.3); Sp =98f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
		1998–2000 (IN)	KLCC10, KLCC11, KLCC20, KLCD00, KLCD01, KLCD04, KLCD10, KLCD11, KLCD96, KLCD97, KLEF13e	1,026	PPV =99.8 (99.3–100)	DS	Møller C et al. Ugeskr laeger. 2002^Citation156
KLCD10	Total vaginal hysterectomy	1977–1988 (IN)	61040	157	PPV =73.9 (66.5–80.1); NPV =100;f Se =93.6 (87.8–96.7); Sp =99f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KLCD11	Supravaginal hysterectomy	1977–1988 (IN)	61000	184	PPV =91.3 (86.3–94.6); NPV =100;f Se =88.0 (82.6–91.8); Sp =100f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KLCD30	Radical hysterectomy	1977–1988 (IN)	61100	91	PPV =90.1 (82.3–94.7); NPV =100;f Se =96.5 (90.1–98.8); Sp =100f	DS	Kjaergaard J et al. J Clin Epidemiol. 2002^Citation68
KLEF	Vaginal prolapse surgery	1996–1998 (IN)	KLCD10, KLDC10, KLEF00, KLEF03, KLEF10, KLEF13, KLEF40, KLEF53, KLFE20	296	PPV =69.3 (63.8–74.2)	MR	Ottesen M. Ugeskr Laeger 2009^Citation157
KMAA00A	Amniocentesis	2001 (IN)	KMAA00A	32	PPV =75.0 (57.9–86.8); NPV =96.8 (95.6–97.7); Se =40.7 (29.1–53.4); Sp =99.3 (98.5–99.6)	MR	Langhoff-Ross et al. 2003^Citation136
KMAC00	Labor induction with artificial rupture of membrane	2001 (IN)	KMAC00	38	PPV =55.3 (39.7–69.9); NPV =99.1 (98.3–99.5); Se =67.7 (50.1–81.4); Sp =98.5 (97.5–99.0)	MR	Langhoff-Ross et al. 2003^Citation136
KMAC05	Artificial rupture of membrane during labor	2001 (IN)	KMAC05	98	PPV =80.6 (71.7–87.2); NPV =79.9 (77.3–82.2); Se =27.6 (22.8–33.1); Sp =97.7 (96.5–98.6)	MR	Langhoff-Ross et al. 2003^Citation136
KMAE	Vacuum extraction	2001 (IN)	KMAE	105	PPV =97.1 (91.9–99.0); NPV =99.4 (98.7–99.7); Se =99.4 (88.4–97.4); Sp =99.7 (99.1–99.9)	MR	Langhoff-Ross et al. 2003^Citation136
KMBA	Removal of placenta	2001 (IN)	KMBA	33	PPV =81.8 (65.6–91.4); NPV =99.3 (98.6–99.6); Se =77.1 (61.0–87.9); Sp =99.5 (98.8–99.8)	MR	Langhoff-Ross et al. 2003^Citation136
KMBC10	Vaginal stitching	2001 (IN)	KMBC10	87	PPV =6.9 (3.2–14.2); NPV =99.8 (99.2–99.9); Se =75.0 (40.9–92.9); Sp =91.4 (89.4–93.0)	MR	Langhoff-Ross et al. 2003^Citation136
KMBC30	Perineal stitching (excl sphincter)	2001 (IN)	KMBC30	242	PPV =60.3 (54.1–66.3); NPV =85.0 (82.1–87.4); Se =57.9 (51.8–63.9); Sp =86.2 (83.4–88.6)	MR	Langhoff-Ross et al. 2003^Citation136
KMBC33	Perineal stitching (incl sphincter)	2001 (IN)	KMBC33	25	PPV =92.0 (75.0–97.8); NPV =98.5 (97.5–99.1); Se =62.2 (46.1–75.9); Sp =99.8 (99.2–99.9)	MR	Langhoff-Ross et al. 2003^Citation136
KMCA	Cesarean section	2001 (IN)	KMCA	185	PPV =97.8 (94.6–99.2); NPV =99.6 (98.9–99.8); Se =97.8 (94.6–99.2); Sp =99.6 (98.9–99.8)	MR	Langhoff-Ross et al. 2003^Citation136
KN	Orthopedic surgery	2004 (IN)	n/a	554	PPV =63.2 (59.1–67.1)	MR	Lass et al. Ugeskr laeger. 2006^Citation158
KPBE2–KPBE3	Upper limb embolectomy	1990–2002 (IN)	86823–86824, PBE20, PBE30	1,134	PPV =97.3 (96.2–98.1)	MR	Andersen LV et al. Clin Epidemiol. 2009^Citation159
KTMD00	Episiotomy (incl stitching)	2001 (IN)	KTMD00	130	PPV =96.9 (92.4–98.8); NPV =99.6 (98.9–99.9); Se =97.7 (93.4–99.2); Sp =99.5 (98.8–99.8)	MR	Langhoff-Ross et al. 2003^Citation136
Other treatments (B)
BAFA7	Infiltration anesthesia	2001 (IN; A/Be)	BAFA7	338	PPV =60.1 (54.8–65.1); NPV =85.9 (82.9–88.4); Se =70.2 (64.7–75.2); Sp =79.5 (76.2–82.4)	MR	Langhoff-Ross et al. 2003^Citation136
BAFA80	Acupuncture	2001 (IN; A/Be)	BAFA80	36	PPV =75.0 (58.9–86.3); NPV =98.3 (97.3–98.9); Se =61.4 (46.6–74.3); Sp =99.1 (98.3–99.5)	MR	Langhoff-Ross et al. 2003^Citation136
BAFA81	Inhalation anesthesia with nitrous oxide	2001 (IN; A/Be)	BAFA81	85	PPV =76.5 (66.4–84.2); NPV =80.6 (77.9–83.0); Se =25.9 (20.9–31.7); Sp =97.5 (96.1–98.4)	MR	Langhoff-Ross et al. 2003^Citation136
BAFA87	Intracutaneous sterile water	2001 (IN; A/Be)	BAFA87	20	PPV =85.0 (64.0–94.8); NPV =96.0 (94.6–97.0); Se =29.3 (19.2–42.0); Sp =99.7 (99.1–99.9)	MR	Langhoff-Ross et al. 2003^Citation136
BFHC92	Inotropes/vasopressors in shock patients	2005–2012 (IN)	BFHC92–BFHC93, BFHC95 (excl BFHC93E-H) (+ R570–R572, A41.9A)	72	PPV =88.9 (79.6–94.3)	MR	Lauridsen MD. BMC Med Res Methodol. 2015^Citation147
BGDA	Mechanical ventilation in ICU patients	2005–2010 (IN)	NABE/NABB + BGDA0	50	PPV =100 (92.9–100)	MR	Blichert-Hansen et al. Clin Epidemiol. 2013^Citation160
BJFD	Acute dialysis in ICU admitted patients	2005–2010 (IN)	NABE/NABB + BJFD00/BJFD02	50	PPV =98.0 (89.5–99.7)	MR	Blichert-Hansen et al. Clin Epidemiol. 2013^Citation160
BKHD0	Uterotonic drugs following birth	2001 (IN; A/Be)	BKHD0	57	PPV =12.3 (6.1–23.3); NPV =98.8 (97.9–99.3); Se =35.0 (18.1–56.7); Sp =95.5 (94.1–96.6)	MR	Langhoff-Ross et al. 2003^Citation136
BKHD20	Induction with prostaglandins	2001 (IN; A/Be)	BKHD20	51	PPV =98.0 (89.7–99.7); NPV =93.4 (91.8–94.7); Se =41.3 (33.0–50.2); Sp =99.9 (99.4–100)	MR	Langhoff-Ross et al. 2003^Citation136
BKHD3	Labor induction medication	2001 (IN; A/Be)	BKHD3	298	PPV =83.6 (78.9–87.3); NPV =92.5 (90.5–94.1); Se =80.0 (75.3–84.1); Sp =94.0 (92.2–95.4)	MR	Langhoff-Ross et al. 2003^Citation136
BKQA0	Bath	2001 (IN; A/Be)	BKQA0	67	PPV =85.1 (74.7–91.7); NPV =74.5 (71.6–77.1); Se =18.6 (14.7–23.4); Sp =98.6 (97.5–99.3)	MR	Langhoff-Ross et al. 2003^Citation136
BWGC1	Radiation therapy to the bone in patients with prostate (P) or breast (B) cancer	2000–2005	BWGC1 (+ C61.9/C50)	16 P; 10 B	PPVP =75.0 (50.5–89.8); NPVP =83.3 (74.0–89.8); PPVB =60.0 (31.3–83.2); NPVB =95.6 (89.1–98.3); SeP =46.2 (28.8–64.5); SpP =94.6 (86.9–97.9); SeB =60.0 (31.3–83.2); SpB =95.6 (89.1–98.3)	MR	Jensen AØ et al. Clin Epidemiol. 2009^Citation65
BWHA	Chemotherapy for colorectal cancer	2009–2010	BWHA1–BWHA2, BOHJ19B	35	PPV =97.1 (85.5–99.5); NPV =93.3 (70.2–98.8); Se =97.1 (85.5–99.5); Sp =93.3 (70.2–98.8)	MR; hospital pharmacy production systems	Lund JL et al. Clin Epidemiol. 2013^Citation161
BWHB40	Bisphosphonate therapy in cancer patients	2005–2009	BWHB40	60	PPV =98.3 (91.1–99.7)	MR	Nielsson MS et al. Clin Epidemiol 2012^Citation162
BWHC	Gonadotropin-releasing hormone agonist in prostate cancer patients	2002–2008	BWHC	100	PPV =93.0 (86.3–96.6); NPV =94.0 (87.5–97.2); Se =93.9 (87.4–97.2); Sp =93.1 (86.4–96.6)	MR	Jespersen CG et al. Clin Epidemiol. 2012^Citation155
ATC codes (M)
MJ06BB16	Palivizumab	1999–2010	MJ06BB16	182	PPVMR =91.7 (80.4–96.7); NPVMR =59.0 (53.3–64.5); SeMR =97.8 (20.5–33.9); SpMR =26.7 (94.4–99.1); PPVPR =90.7 (85.6–94.1); NPVPR =98.4 (97.9–98.9); SePR =79.7 (73.7–84.6); SpPR=99.4 (99.0–99.6)	MR; PR	Haerskjold A et al. Clin Epidemiol. 2015^Citation163
Anesthesia and intensive care (N)
NAAC	General anesthesia	2001 (IN)	NAAC	20	PPV =40.0 (21.9–61.3); NPV =95.9 (94.6–97.0); Se =15.1 (7.9–27.1); Sp =98.9 (98.1–99.4)	MR	Langhoff-Ross et al. 2003^Citation136
NAAD0	Epidural nerve block	2001 (IN)	NAAD0	24	PPV =75.0 (55.1–88.0); NPV =91.8 (89.9–93.3); Se =17.7 (11.5–26.2); Sp =99.4 (98.6–99.7)	MR	Langhoff-Ross et al. 2003^Citation136
NAAD1	Spinal anesthesia	2001 (IN)	NAAD1	35	PPV =77.1 (61.0–87.9); NPV =91.6 (89.8–93.1); Se =22.7 (16.1–31.0); Sp =99.2 (98.4–99.6)	MR	Langhoff-Ross et al. 2003^Citation136
NAAD43	Pudendal nerve block	2001 (IN)	NAAD43	40	PPV =70.0 (54.6–81.9); NPV =95.9 (94.4–97.0); Se =43.1(31.8–55.2); Sp =98.6 (97.6–99.2)	MR	Langhoff-Ross et al. 2003^Citation136
NABB	Intensive care unit admission	2005–2010 (IN)	NABB, NABE	47	PPV =87.2 (74.8–94.0)	MR	Blichert-Hansen et al. Clin Epidemiol. 2013^Citation160
Examinations (U)
UXCC00A	Cardiac CT Angiography	2008–2012	UXCC00A	289	PPV =100 (98.7–100)	MR	Nielsen LH et al. Clin Epidemiol. 2014^Citation164
UXUD88A	Fetal umbilical artery flow velocity measurement	2001 (IN)	UXUD88A	63	PPV =77.8 (66.1–86.3); NPV =94.9 (93.4–96.1); Se =47.6 (38.2–57.1); Sp =98.6 (97.7–99.2)	MR	Langhoff-Ross et al. 2003^Citation136

Notes:

a The ordering corresponds to the SKS browser, ie, ICD-10 for diagnoses and NOMESCO for surgery;

b ICD codes without and with capital letters refer to ICD-8 and ICD-10 codes, respectively;

c reflects the reviewed number of records in the DNPR (ie, the denominator in calculations of PPV). Among obstetric variables, we included only validation results based on >20 diagnoses;

d confidence intervals were calculated using Wilson’s score method;

e information not specified in validation papers, but confirmed through correspondence with authors. Unspecified and unconfirmed data are listed as not available (n/a);

f recalculation of confidence intervals using Wilson’s score method not possible due to insufficient data;

g confidence limit equals 100 due to rounding.

Abbreviations: A, primary diagnosis; AC, anticoagulant therapy; B, secondary diagnosis; COPD, chronic obstructive pulmonary disease; CT, computed tomography; d, day; DVT, deep venous thrombosis; DANMONICA, Danish Monitoring Trends and Determinants in Cardiovascular Disease project; DCR, Danish Cancer Registry; DNPR, Danish National Patient Registry; DS, discharge summaries; echo, echocardiography; ECG, electrocardiography; ED, emergency department; GP, general practitioner; HBV, hepatitis B virus; HCV, hepatitis C virus; HIV, human immunodeficiency virus; ICD, International Classification of Diseases; ICU, intensive care unit; IN, inpatient contact; LABKA, Clinical Laboratory Information System Database; mo, month; MR, medical records; MRI, magnetic resonance imaging; MS, multiple sclerosis; n/a, not available; NPV, negative predictive value; OUT, outpatient contact; PD, Pathology Registry; PE, pulmonary embolism; PPV, positive predictive value; PR, Prescription Registry; PSA, prostate specific antigen; Se, study sample sensitivity; Sp, study sample specificity; ultrasound, ultrasonography; y, year(s); V-P, ventilation-perfusion; VTE, venous thromboembolism; NOMESCO, Nordic Medico-Statistical Committee; wks, weeks.

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