Perianal fistulas in adult patients with Crohn's disease in Germany - a retrospective cross-sectional analysis of claims data from German sickness funds.

INTRODUCTION:  Perianal fistulas (PF) are presumably a frequent extraintestinal manifestation of Crohn's disease (CD), causing significant functional impairment. This study aims to gain representative data on the prevalence, characteristics, and treatment of CD patients suffering from PF in Germany.

MATERIALS AND METHODS:  A retrospective cross-sectional analysis of claims data from several German company health insurance funds included adult patients with CD and PF in 2015. The dataset comprised in- and outpatient services with diagnoses, drug prescriptions, and other patient data. It is representative for age, gender, and region and allows extrapolation to the total German statutory health insurance (SHI) population. A systematic literature review was conducted to discuss these results in the international context.

RESULTS:  A CD prevalence of 299 per 100 000 and a PF prevalence in CD patients of 3.4 % was observed in this cross-sectional study. PF are most prevalent in young age groups (< 24 to 39). One-third of patients with PF received biologics and surgery. Surgical procedures were performed in 31.3 % of PF patients in the inpatient setting and in 4.4 % of PF patients in the outpatient setting. All complicated perianal fistula patients received at least 1 inpatient surgery and 44.8 % received biologic therapy.

DISCUSSION:  This claims data analysis in German patients estimates a CD prevalence in the SHI population that corresponds well to previously reported data. The prevalence rate for PF in CD patients is comparable with a previous cross-sectional German claims data analysis but is markedly lower than cumulative risks reported in longitudinal cohort studies. PF patients are young and treatment intensive with one-third requiring biologic treatment or inpatient surgery.