Inflammatory bowel disease and risk of severe COVID‐19: A nationwide population‐based cohort study in Sweden

BACKGROUND: There are concerns that individuals with chronic immune‐mediated diseases are at increased risk of COVID‐19 and related severe adverse outcome, including intensive care admission or death. We aimed to explore the absolute and relative risk of severe COVID‐19 in inflammatory bowel disease (IBD). METHODS: This population‐based cohort study used nationwide registers in Sweden, with 67,292 individuals with a diagnosis of IBD 1969–2017 (Crohn's disease, n = 21,599; ulcerative colitis: n = 43,622; IBD‐unclassified: n = 2071) and alive on 1 February 2020. Patients with IBD were matched to up to five controls from the general population (n = 297,910). Cox regression estimated hazard ratios (HRs) for (i) hospital admission with laboratory‐confirmed COVID‐19 as the primary diagnosis, and (ii) severe COVID‐19 (composite outcome consisting of (a) COVID‐19 intensive care admission, or (b) death from COVID‐19 or (c) death within 30 days of COVID‐19 hospital admission), were calculated. Analyses were conditioned on age, sex, calendar period, and county and adjusted for other comorbidities. RESULTS: Between 1 February and 31 July 2020, 179 (0.27%) IBD patients and 500 (0.17%) general population controls were admitted to hospital with COVID‐19 (adjusted HR [aHR] = 1.43; 95% CI = 1.19–1.72). The corresponding numbers for severe COVID‐19 was 65 (0.10%) and 183 (0.06%; aHR = 1.11; 95% CI = 0.81–1.52). Adjusted HRs were similar in Crohn's disease and ulcerative colitis. In a propensity score‐matched model taking comorbidity into account until 2016, the increased risk for COVID‐19 hospital admission remained (aHR = 1.32; 1.12–1.56), but there was no increased risk of severe COVID‐19 (aHR = 1.12; 0.85–1.47). CONCLUSIONS: While individuals with IBD were more likely to be admitted to hospital for COVID‐19 than the general population, the risk of severe COVID‐19 was not higher.