Prevalence of Fistulizing Crohn's Disease in the United States: Estimate From a Systematic Literature Review Attempt and Population-Based Database Analysis

Background: Fistulas may arise as a relevant complication of Crohn's disease (CD). Despite their clinical significance and the substantial burden imposed on patients, limited data are available on the epidemiology of fistulizing CD in the United States. Methods: A systematic literature review was conducted to identify data published between 1970 and 2017 on the epidemiology of fistulas in patients with CD, with the aim to estimate the number of prevalent cases in the United States. Retrieved titles and abstracts were screened by 2 independent researchers for inclusion criteria (US population-based studies reporting data on the epidemiology of fistulizing CD). To validate the literature-based estimate, data from a US claims database (Truven Health MarketScan database) were analyzed. This database has broad geographic coverage, with health care data for >60 million patients during the period of the analysis. Results: The literature search retrieved 7 articles for full-text review, and only 1 met the criteria for inclusion. This study described the cumulative incidence of fistulas in a CD population from Minnesota over 20 years. From the reported data, the estimated number of prevalent cases with fistulizing CD in the United States was similar to 76,600 in 2017 (similar to 52,900 anal, similar to 7400 rectovaginal, similar to 2300 enterocutaneous, and similar to 14,100 internal). Analysis from the US health care database resulted in an estimated number of similar to 75,700 patients, confirming the robustness of the original estimate from the literature. Conclusions: Based on 2 separate analyses, the estimated number of patients with fistulizing CD in the United States is similar to 77,0(X) patients.