Multiple sclerosis and the association with inflammatory bowel disease: Results from a retrospective cohort study.

This retrospective cohort study aimed to investigate the incidence rates (IRs) of inflammatory bowel disease (IBD), including ulcerative colitis (UC), Crohn's disease (CD), and noninfectious colitis, in patients with Multiple Sclerosis (MS) and matched controls identified from January 1, 2008 through December 31, 2022. The study population was identified from the Optum Clinformatics® Data Mart Database (Optum® CDM), using ICD-9/10 diagnosis codes. Patients with MS and controls matched 1:5 on age, sex, and calendar year of end of enrollment were included in the study. The study population was followed from the index date until the date of an IBD diagnosis, disenrollment, or end of the study period (December 31, 2022), whichever came first. IRs of diagnosed IBD were calculated. Index date was defined as the date of the first MS diagnosis. In this study, 27,794 patients with MS and 138,970 matched controls were identified. 1,427 patients diagnosed with IBD (IR = 25.54 per 1000 person-years [95% CI=24.22-26.87]) were observed in patients with MS and 6,975 patients diagnosed with IBD (IR = 14.58 per 1000 person-years [95% CI=14.24-14.92]) were observed in non-MS matched controls. Patients with MS were more likely to be non-Hispanic white and had a higher incidence rate of IBD (adjusted incidence rate ratio (aIRR)) = 1.45 (95% CI= 1.37-1.52); compared to matched controls. This study reported significantly higher incidence rates of IBD among patients with MS compared to non-MS matched controls.