Positive predictive value of peptic ulcer diagnosis codes in the Danish National Patient Registry

Figures & data

Table 1 Characteristics of 200 outpatients with a first-time diagnosis of peptic ulcer disease endoscopically examined at Aarhus University Hospital, Denmark during 1995–2006

Characteristics	Patients sampled, n (%)	Patients included, n (%)
All	200 (100)	182 (100)
Sex
Female	85 (43)	79 (43)
Male	115 (58)	103 (57)
Age at ulcer diagnosis
0–39 years	33 (17)	27 (15)
40–59 years	70 (35)	65 (36)
60+ years	97 (49)	90 (49)
Year of diagnosis
1995–1998	69 (35)	62 (34)
1999–2002	69 (35)	59 (32)
2003–2006	62 (31)	61 (34)
Recorded location of ulcer
Gastric	100 (50)	93 (51)
Duodenal	100 (50)	89 (49)
Recorded status of ulcer in the DNPR
Acute	79 (40)	71 (39)
Chronic	63 (32)	57 (31)
Unspecified	58 (29)	54 (30)
Complicated ulcer
Yes	2 (1)	1 (1)
No	198 (99)	181 (99)

Abbreviation: DNPR, Danish National Patient Registry.

Table 2 Positive predictive values of ICD-10 codes of recent peptic ulcers among 200 selected patients at Aarhus University Hospital, Denmark during 1995–2006, validated using descriptions from the gastroscopic examinations as standard reference

	Patients sampled, n	Patients included, n	Confirmed diagnoses, n	PPV (%)	95% CI
Overalla	200	182	174	95.6	91.5–98.1
Location of ulcerb
Gastric	100	93	84	90.3	82.4–95.5
Duodenal	100	89	84	94.4	87.4–98.2
Type of diagnosis
Primary	188	172	166	96.5	92.6–98.7
Secondary	12	10	8	80.0	44.4–97.5
Time of diagnosis
1995–1998	69	62	60	96.8	88.8–99.6
1999–2002	69	59	55	93.2	83.5–98.1
2003–2006	62	61	59	96.7	88.7–99.6

Notes:

a All confirmed patients with peptic ulcers (not all were correctly classified by location).

b Only ulcers correctly classified by location were confirmed.

Abbreviations: PPV, positive predictive value; CI, confidence interval; ICD-10, International Classification of Diseases, 10^th revision.

Table S1 Description of endoscopic findings among 182 patients with a diagnosis code of gastric or duodenal ulcer

Discharge diagnosis	Endoscopic description, n (%)
	Gastric ulcer	Duodenal ulcer	Gastric ulcer and duodenal ulcer	Gastric cicatrices	Duodenal cicatrices	Gastritis	Esophagitis	Total
Gastric ulcer	72 (77)	2 (2)	3 (3)	9 (10)	0 (0)	6 (6)	1 (1)	93 (100)
Duodenal ulcer	4 (4)	81 (91)	2 (2)	0 (0)	1 (1)	1 (1)	0 (0)	89 (100)