Inflamm Bowel Dis. 2022 Jul 20;izac131. doi: 10.1093/ibd/izac131. Online ahead of print.

Susan Hutfless ^1 2, Ryan A Jasper ³, Aman Tilak ⁴, Tamoghna Ghosh ⁴, Saurabh Kedia ⁵, Simon Liu ⁶, Nathalie H Urrunaga ⁷, Matthew Josephson ⁸, Arshit Narang ⁴, Steve Miller ⁹, Po-Hung Chen ¹, Shelly Joseph ¹⁰, Steven R Brant ^1 11

Author information

¹Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, USA.

²Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.

³Department of Applied Mathematics and Statistics, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA.

⁴Department of Medicine, All India Institute of Medical Sciences, New Delhi, India.

⁵Department of Gastroenterology, All India Institute of Medical Sciences, New Delhi, India.

⁶Medical Genomics Unit, National Human Genome Research Institute, Bethesda, MD, USA.

⁷Division of Gastroenterology and Hepatology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.

⁸Division of Gastroenterology and Hepatology, Albany Medical College, Albany, NY, USA.

⁹Division of Pediatric Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

¹⁰Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, NYU Grossman School of Medicine, New York, NY, USA.

¹¹Division of Gastroenterology and Hepatology, Department of Medicine, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, USA.

Abstract

Background: We sought to review Crohn's disease (CD) case definitions that use diagnosis, procedure, and medication claims.

Methods: We searched PubMed and Embase from inception through January 31, 2022, using terms related to CD, inflammatory bowel disease, administrative claims, or validity. Each article was scrutinized by 2 authors independently screening and abstracting data. Collected data included participant characteristics, case definition characteristics, and case definition validity. When diagnostic accuracy was provided for multiple case definitions, we extracted the case definition selected by the authors. All diagnostic accuracy characteristics were captured.

Results: We identified 30 studies that evaluated a case definition using claims data to identify CD patients. The most common case definition included counts of diagnosis codes (57%) followed by a combination of diagnosis codes and medications (20%). All but 1 study validated the case definition with a medical chart review. In 2 studies, the patient's primary care provider completed a survey to confirm disease status. The positive predictive value of the case definitions ranged from 18% (≥1 code at a single U.S. health plan) to 100% (≥1 code plus a relevant prescription at a U.S. hospital). More complex case definitions (eg, ≥1 code + prescription or ≥2 codes) had lower variability in positive predictive value (≥80%) and specificity (≥85%) than the ≥1 code requirement.

Conclusions: Health services researchers should validate case definitions in their research cohorts. When such validation cannot be performed, we recommend using a more complex case definition. Studies without a validated CD case definition should use sensitivity analyses to confirm the robustness of their results.