IBD a risk factor for acute coronary syndrome?

Individuals with inflammatory bowel disease (IBD) appear to be at increased risk of acute coronary syndrome (ACS) compared with those from the general population, according to a Swedish nationwide cohort study.

The study included 76,517 patients with IBD (mean age 42.8 years, 51 percent men) and 757,141 general population comparators. The patients and comparators were matched based on birth year, sex, calendar year, and area of residence. Semi-parametric Cox proportional hazard models were used to estimate the risk of ACS in relation to IBD.

Of the patients with IBD, 22,732 had Crohn's disease (CD), 42,194 had ulcerative colitis (UC), and 11,591 had unclassified IBD. Compared with comparators, patients with IBD had more frequent healthcare visits and a higher prevalence of comorbidities before the index date.

Over a median follow-up of 8 years, ACS was diagnosed in 2,546 patients with IBD and in 19,598 comparators (37.5 vs 28.0 per 10,000 person-years). The risk of ACS was 30-percent higher in the presence of IBD (hazard ratio, 1.30, 95 percent confidence interval, 1.24–1.35), with roughly one extra case of ACS in 100 IBD patients followed for 10 years.

The highest risk of ACS was found among patients with elderly-onset IBD (≥60 years) and among those with CD or UC who had extra-intestinal manifestations.

The findings underscore the need for future studies to explore the mechanisms underlying the elevated ACS risk in IBD patients.