Predictive value of pediatric thrombosis diagnoses in the Danish National Patient Registry

Figures & data

Table 1 ICD-10 diagnoses of thrombosis in children (0–18 years of age) recorded in the Danish National Patient Registry (DNPR) during the period 1994–2006

Thrombosis localization		ICD-10 diagnosis codes	Number of first-time diagnoses recorded in the DNPR n (%)
Venous	Cerebral sinovenous Retinal veins Pulmonary embolism Vena cava, renal veins, hepatoportal veins Deep veins of extremities Venous thrombosis in relation to pregnancy	I67.6, I63.6, G0.8 H34.8 I26 I81–I82 I80.1–I80.9 O22.5A, O87.3, O22.3, O22.8–9, O87A–F, O87.1	57 (5.0) 4 (0.4) 105 (9.2) 103 (9.1) 391 (34.4) 0
Arterial	Ischemic stroke Retinal arteries Arteries of extremities and/or aorta Renal arteries Myocardial infarction	I63–I64 H34.1–H34.2 I74 N28.0A, N28.0D I21	364 (32.0) 4 (0.4) 61 (5.4) 0 42 (3.7)
Miscellaneous (combined arterial and venous)	Mesenterial Retinal	K55.0H, K55.0C H34, H34.9	0 7 (0.6)
All			1138 (100)

Table 2 Diagnostic tools for verified diagnosis of symptomatic thrombosis

Diagnostic method	Venous thrombosis			Arterial thrombosis			Retinal occlusion n = 3 n (%)
	CSVT n = 38 n (%)	DVTb n = 259 n (%)	PE n = 48 n (%)	AISc n = 209 n (%)	Extremities/aorta n = 37 n (%)	MI n = 4 n (%)
MR (± CT)	32 (84.2)	9 (3.5)	1 (2.1)	144 (68.9)	2 (5.4)	–	–
CT alone	6 (16.2)	9 (3.5)	10 (20.8)	64 (30.3)	2 (5.4)	–	–
Ultrasonography (± other tools)	–	214 (82.6)	–	–	14 (37.8)	–	–
Ventilation-perfusion lung scan (± other tools)	–	–	34 (70.8)	–	–	–	–
Angiography alone	–	30 (11.6)	1 (2.1)	–	13 (35.1)	2 (50.0)	1 (33.3)
Autopsy	–	–	1 (2.1)	–	–	1 (25.0)	–
Miscellaneousa	–	–	1 (2.1)	–	8 (21.6)d	1 (25.0)	2 (66.7)

Notes:

a Miscellaneous diagnostic tools are i) findings during surgery (PE and arterial thrombosis), ii) biochemical markers and/or electrocardiogram findings in MI, iii) ophthalmoscopic examination in retinal occlusion.

b Method of examination was unknown in one patient with DVT in the extremities and abdomen.

c Type of brain scan was unknown in one patient with AIS.

d Two newborns were included based on clinical signs of a threatened limb. Imaging or surgery was not performed.

Abbreviations: AIS, arterial ischemic stroke; CT, computed tomography; CSVT, cerebral sinovenous thrombosis; DVT, deep venous thrombosis; MI, myocardial infarction; MR, magnetic resonance; PE, pulmonary embolism.

Table 3 The positive predictive value (PPV) of arterial and venous thrombosis diagnoses in patients aged 0–18 years in the Danish National Patient Registry

Diagnoses	PPV% (95% CI)a, nconfirmed/ntotalb
	All departments	Emergency departments	Wards
			Total	Neonates (<28 days)	Children (28 days–14 years)	Adolescents (15–18 years)
Total	53.7 (50.8–56.7) 598/1112	7.4 (13.5–11.3) 13/176	62.5 (59.4–65.6) 585/936	77.4 (68.7–84.7) 89/115	51.2 (46.0–56.4) 192/375	68.2 (63.6–72.5) 304/446
All venous thrombosisc	53.9 (50.0–57.8) 345/640	7.4 (3.6–13.2) 10/135	66.3 (62.0–70.5) 335/505	82.4 (65.5–93.2) 28/34	39.0 (30.4–48.2) 48/123	74.4 (69.5–78.9) 259/348
CSVT	66.7 (52.9–78.6) 38/57	0/2	69.1 (55.2–80.9) 38/55	87.5 (47.4–99.7) 7/8	50.0 (29.1–70.9) 12/24	82.6 (61.2–95.1) 19/23
PE	47.5 (37.5–57.7) 48/101	0/25	63.2 (51.3–73.9) 48/76	0/1	16.7 (2.1–48.4) 2/12	73.0 (60.4–83.4) 46/63
Thrombosis of vena cava, renal veins, hepatoportal veins	62.8 (52.6–72.1) 64/102	9.1 (0.3–41.3) 1/11	69.2 (58.7–78.7) 63/91	94.7 (74.0–99.9) 18/19	52.8 (35.5–69.6) 19/36	72.2 (54.8–85.8) 26/36
DVT in extremities	51.3 (46.2–56.5) 195/380	9.3 (4.3–16–9) 9/97	65.7 (59.9–71.2) 186/283	50.0 (11.8–88.2) 3/6	29.4 (17.5–43.8) 15/51	74.3 (68.1–79.9) 168/226
All arterial thrombosisd	53.6 (49.0–58.2) 253/472	7.3 (15.4–19.9) 3/41	58.0 (53.2–62.7) 250/431	75.3 (64.5–84.2) 61/81	57.1 (50.8–63.3) 144/252	45.9 (35.8–56.3) 45/98
AIS	58.1 (52.8–63.2) 209/360	4.6 (1.2–22.8) 1/22	61.5 (56.1–66.8) 208/338	73.9 (61.5–84.0) 48/65	62.3 (55.3–68.9) 129/207	47.0 (34.6–59.7) 31/66
Thrombosis in arteries of the extremities, aorta	62.7 (49.2–75.0) 37/59	25.0 (0.6–80.6) 1/4	65.5 (51.4–77.8) 36/55	92.3 (64.0–99.8) 12/13	59.1 (36.4–79.3) 13/22	55.0 (31.5–76.9) 11/20
Myocardial infarction	10.5 (2.9–24.8) 4/38	7.7 (0.2–36.0) 1/13	12.0 (2.6–31.2) 3/25	50.0 (1.3–98.7) 1/2	12.5 (1.6–38.4) 2/16	0/7
Retinal occlusionse	20.0 (4.3–48.1) 3/15	0/2	23.1 (5.0–53.8) 3/13	0/1	0/7	60.0 (14.7–94.7) 3/5

Notes:

a 95% confidence interval.

b Number of confirmed diagnoses/number of recorded diagnoses.

c Including cerebral sinovenous thrombosis (CSVT), pulmonary embolism (PE), and deep venous thrombosis (DVT) in the extremities and miscellaneous veins.

d Including arterial ischemic stroke (AIS), thrombosis in the arteries of limbs and aorta, myocardial infarction (MI), and retinal occlusions.

e One arterial, one venous, one bland.

Abbreviation: CI, confidence interval.

Table 4 The positive predictive value (PPV) of discharge diagnoses of venous and arterial thrombosis in the subgroup of in-patients (0–18 years) in the Danish National Patient Registry (DNPR)

Subgroups	n	PPV% (95% CI)
Male	400	62.5 (57.6–67.3)
Female	536	62.5 (58.3–66.6)
Primary diagnosis	615	66.8 (63.0–70.5)
Secondary diagnosis	321	54.2 (48.6–59.8)
Hospital stay <3 days	334	44.6 (39.2–50.1)
Hospital stay ≥3 days	602	72.4 (68.7–76.0)
University hospitals	354	64.4 (59.2–69.4)
Regional hospitals	582	61.3 (57.3–65.3)
Study periods:
1994–1998	321	61.4 (55.8–66.7)
1999–2002	278	63.0 (57.0–68.6)
2003–2006	337	63.2 (57.8–68.4)

Abbreviations: n, recorded diagnoses in DNPR; CI, confidence interval.

Table 5 Unconfirmed thrombosis diagnoses

Registered thrombosis diagnosis	Unconfirmed diagnoses
	Total n	Asymptomatic course n (%)	Lack of confirmation from imaging n (%)	Incorrect code n (%)	Miscellaneousa n (%)
CSVT n = 57	19	0	7 (36.8)	9 (47.4)	3 (15.8)
PE n = 101	53	2 (3.8)	41 (77.4)	8 (15.1)	2 (3.8)
Thrombosis of vena cava, renal veins, hepatoportal veins n = 102	38	6 (15.8)	20 (52.6)	8 (21.1)	4 (10.6)
DVT in extremities n = 380	185	1 (0.5)	157 (84.9)	26 (14.1)	1 (0.5)
AIS n = 360	151	6 (4.0)	102 (67.6)	23 (15.2)	20 (13.3)
Thrombosis in arteries of the extremities, aorta n = 59	22	1 (4.6)	14 (63.6)	4 (18.2)	3 (13.6)
MI n = 38	34	0	6 (17.7)	19 (55.9)	9 (26.5)
Retinal occlusions n = 15	12	1 (8.3)	2 (16.7)	8 (66.7)	1 (8.3)
Total n = 1112	514	17 (3.3)	349 (67.9)	105 (20.4)	43 (8.4)

Notes:

a Miscellaneous causes for exclusion: i) diagnosis before or after study period, ii) thrombosis in stents (n = 2 arterial noncerebral), iii) diagnosis of thrombosis due to meningococcal infection (n = 1 arterial noncerebral), iv) lack of supporting ophthalmoscopic findings in retinal occlusions and biochemical markers and/or electrocardiogram findings in MI.

Abbreviations: AIS, arterial ischemic stroke; CSVT, cerebral sinovenous thrombosis; DVT, deep venous thrombosis; MI, myocardial infarction; PE, pulmonary embolism.