Patients with inflammatory bowel disease have an increased risk of myocardial infarction: a nationwide study

Background Inflammatory bowel disease (IBD) is accompanied by various extraintestinal manifestations including systemic inflammation and hypercoagulability, which may increase the risk of atherosclerosis and ischaemic heart disease. Aim To investigate whether IBD is associated with an increased risk of myocardial infarction (MI), stroke or death Methods The International Classification of Disease, 10th edition codes and the claim codes for rare diseases were used to identify candidates from National Health Insurance Service (NHIS) of South Korea. Patients diagnosed with Crohn's disease (CD) or ulcerative colitis (UC) between 2006 and 2009 were age-matched 1:3 with NHIS enrolees without IBD. The primary outcomes included newly developed MI, stroke and death. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox regression models. Results We identified 10 708 patients diagnosed with CD and 26 769 with UC. MI risk was higher in CD patients than in controls (incidence ratio (IR) 1.64 per 1000 person-years, HR, 1.80; 95% CI, 1.47-2.21), and this trend was more prominent among patients aged <40 years (IR 0.69 per 1000 person-years, HR, 2.96; 95% CI, 1.96-4.47) and among female patients (IR 2.35 per 1000 person-years, HR, 2.18; 95% CI, 1.61-2.94). In contrast, only female patients with UC had an increased risk of MI (IR 2.01 per 1000 person-years, HR, 1.33; 95% CI, 1.13-1.56). Conclusions The risk of MI risk is higher in patients with CD than in the general population, and this trend is stronger in female patients and those aged <40 years.