To Örebro University

BACKGROUND: There are conflicting data on the risk of acute coronary syndrome (ACS) in patients with inflammatory bowel disease (IBD). Only a few previous reports include patients diagnosed during the last decade. AIM: To assess and compare the risk of ACS between patients with IBD and the general population.

METHODS: In this cohort study, we used nationwide registers to identify patients diagnosed with IBD in Sweden 2003-2021. Every patient was matched by birth year, sex, calendar year and area of residence with up to 10 general population comparators. The primary outcome was incident ACS. We used semi-parametric Cox proportional hazard models to estimate hazard ratios (HRs).

RESULTS: We identified 76,517 patients with IBD (Crohn's disease [CD], N = 22,732; ulcerative colitis [UC], N = 42,194 and IBD-unclassified, N = 11,591) and 757,141 comparators. During a median follow-up of 8 years, 2546 patients with IBD (37.5/10,000 person-years) were diagnosed with ACS compared with 19,598 (28.0/10,000 person-years) among comparators (HR 1.30; 95% confidence interval 1.24-1.35) after adjustments for confounding factors, and approximately one extra case of ACS in 100 IBD patients followed for 10 years. The highest HRs for ACS were in patients with elderly onset IBD (≥60 years) and among patients with CD or UC with extra-intestinal manifestations. No increased HRs were observed in patients diagnosed with IBD before the age of 40.

CONCLUSION: In this contemporary cohort of patients with IBD, exposed to modern IBD care, there was an increased risk for ACS compared with individuals from the general population.