Multiple sclerosis and inflammatory bowel disease: A systematic review and meta‐analysis

BACKGROUND: Multiple sclerosis (MS) and inflammatory bowel disease (IBD) are two autoimmune diseases that seriously affect patients' quality of life. Previous studies have established an association between MS and IBD, including Crohn's disease (CD) and ulcerative colitis (UC), but the results were inconsistent. The aim of this study was to quantify the prevalences of and the association between MS and IBD. METHODS: The PubMed, Web of Science, and Embase databases were searched through November 2020 for studies reporting data on MS among patients with IBD and vice versa. The main outcomes were the proportion of MS in patients with IBD and vice versa, as well as the association (risk ratio [RR]) of IBD in MS and that of MS in IBD. RESULTS: Based on the analysis of 17 studies, the prevalence of MS in patients with IBD was 0.2% (95% CI 0.1–0.4%), while the prevalence of IBD in patients with MS was 0.6% (95% CI 0.4–0.9%). Patients with MS had a higher prevalence of IBD than controls (RR = 1.53, 95% CI 1.38–1.70, p < 0.00001). There was a similarly high risk of developing CD (RR 1.41, 95% CI 1.14–1.74, p = 0.001) or UC (RR 1.42, 95% CI 1.17–1.71, p = 0.0003) in patients with MS (p for subgroup differences: 0.97). Patients with IBD had a higher prevalence of MS than controls (RR = 1.91, 95% CI 1.06–3.45, p = 0.03). CONCLUSIONS: Clinicians should be aware of the increased risk of IBD or MS comorbidity during the diagnostic process. Systematic diagnosis and management at an earlier stage are suggested.