Atrial fibrillation and risk of myocardial infarction by sex and time since diagnosis

Abstract Background/Introduction Atrial fibrillation (AF) and myocardial infarction (MI) are major contributors to the global burden of cardiovascular disease. While AF is a known risk factor for MI, the sex-specific risk patterns and temporal relationship between AF and MI subtypes — ST-segment elevation MI (STEMI) and non-ST-segment elevation MI (NSTEMI) — remain unclear. Purpose To examine the sex-specific risk of total MI, STEMI and NSTEMI in women and men with AF overall, and by time since AF diagnosis in a general population of adults and elderly. Methods We followed 25,132 participants from a population-based cohort study without prevalent AF and MI at baseline in 1994-95 through 2021. Cox proportional- and Fine-Gray subdistribution- hazard regression assessed AF as a risk factor for MI, STEMI and NSTEMI overall and by time since AF diagnosis (0 to 0.5, 0.5 to 1, 1 to 5, 5 to 10 and ≥10 years). Subdistribution hazard ratios (sHRs) with confidence intervals (CIs) accounted for competing risks. Results Compared with participants without AF, AF overall was associated with increased hazard of MI in women (sHR 1.39, 95% CI 1.12–1.72), but not in men. In women with AF, hazard of MI was significantly increased 1–10+ years since AF diagnosis, peaking at ≥10 years (sHR 1.75, 95% CI 1.07–2.84). In men with AF, hazard was significantly increased within the first six months since AF diagnosis (sHR 2.27, 95% CI 1.45–3.54), but not thereafter. For STEMI, a significantly increased hazard was observed only in men within the first six months since AF diagnosis. For NSTEMI, women had significantly elevated hazards 1-10+ years since AF, and men within the first year. Conclusions AF is a risk factor for MI in both sexes, but risk patterns differ. Women are at increased hazard of NSTEMI 1-10+ years since AF diagnosis, while men are at increased hazard of STEMI within the first six months and of NSTEMI within the first year since AF diagnosis. This calls for different approaches to MI prevention in women and men with AF. Women seem to require a longitudinal approach to MI prevention, while men need a more active approach and closer follow-up, particularly during the first 12 months after AF.Graphical abstractFor image description, please refer to the figure legend and surrounding text. Table of main findingsFor image description, please refer to the figure legend and surrounding text.