Table 3.

Comparison of performances of various published algorithms to define Crohn’s disease or ulcerative colitis in an electronic medical record cohort

Algorithm	Positive Predictive value	Sensitivity	Specificity	Predicted number of patients in the IBD mart
Crohn’s disease
Combined CD model	98 (97 – 100)	69 (65 – 74)	97 (96 – 100)	5,506
5 separate CD ICD-9 codes 10	91 (88 – 94)	66 (61 – 71)	88 (82 – 92)	5,504
1 outpatient/inpatient CD ICD-9 code and 1 endoscopy12	85 (80 – 89)	53 (48 – 58)	81 (75 – 86)	4,914
4 outpatient or 2 inpatient CD ICD-9 codes 9	92 (88 – 95)	65 (60 – 70)	88 (83 – 92)	5,678
Ulcerative colitis
Combined UC model	97 (97 – 100)	79 (75 – 83)	97 (95 – 100)	5,522
5 separate UC ICD-9 codes10	90 (86– 94)	67 (62 – 71)	88 (83 – 92)	4,893
1 outpatient/inpatient UC ICD-9 code and 1 endoscopy12	85 (80 – 89)	51 (46 – 56)	85 (79 – 89)	4,489
4 outpatient or 2 inpatient UC ICD-9 codes 9	89 (85 – 93)	66 (61 – 72)	86 (81 – 91)	5,070