Risk factors for SARS-CoV-2 infection and course of COVID-19 disease in patients with IBD in the Veterans Affair Healthcare System

OBJECTIVE: Our aim was to explore the risk of infection with all classes of inflammatory bowel disease (IBD) medications and the impact of these medications on the disease course in a nationwide cohort of patients with IBD. DESIGN: This was a retrospective national cohort study of patients with IBD in the Veterans Affairs Healthcare System. We categorised IBD medication use immediately prior to the COVID-19 pandemic and used survival analysis methods to study associations with SARS-CoV-2 infection, as well as a combined secondary outcome of COVID-19 hospitalisation or COVID-19-related mortality. RESULTS: The analytical cohort of 30 911 patients was primarily male (90.9%), white (78.6%) and with ulcerative colitis (58.8%). Over a median follow-up of 10.7 months, 649 patients (2.1%) were diagnosed with SARS-CoV-2 infection and 149 (0.5%) met the combined secondary outcome. In adjusted models, vedolizumab (VDZ) use was significantly associated with infection relative to mesalazine alone (HR 1.70, 95% CI 1.16 to 2.48, p=0.006). Patients on no IBD medications had increased risk of the combined secondary outcome relative to mesalazine alone (sub-HR 1.64, 95% CI 1.12 to 2.42, p=0.01), however, no other IBD medication categories were significantly associated with this outcome, relative to mesalazine alone (each p>0.05). Corticosteroid use was independently associated with both SARS-CoV-2 infection (HR 1.60, 95% CI 1.23 to 2.09, p=0.001) and the combined secondary outcome (sub-HR 1.90, 95% CI 1.14 to 3.17, p=0.01). CONCLUSION: VDZ and corticosteroid were associated with an increased risk of SARS-CoV-2 infection. Except for corticosteroids no medications including mesalazine were associated with an increased risk of severe COVID-19.