Sex Differences in Cardiovascular Outcomes of Older Adults After Myocardial Infarction

Background Evidence on the impact of sex on prognoses after myocardial infarction (MI) among older adults is limited. We evaluated sex differences in long-term cardiovascular outcomes after MI in older adults. Methods and Results All patients with MI ≥70 years admitted to 20 Finnish hospitals during a 10-year period and discharged alive were studied retrospectively using a combination of national registries (n=31 578, 51% men, mean age 79). The primary outcome was combined major adverse cardiovascular event within 10-year follow-up. Sex differences in baseline features were equalized using inverse probability weighting adjustment. Women were older, with different comorbidity profiles and rarer ST-segment-elevation MI and revascularization, compared with men. Adenosine diphosphate inhibitors, anticoagulation, statins, and high-dose statins were more frequently used by men, and renin-angiotensin-aldosterone inhibitors and beta blockers by women. After balancing these differences by inverse probability weighting, the cumulative 10-year incidence of major adverse cardiovascular events was 67.7% in men, 62.0% in women (hazard ratio [HR], 1.17; CI, 1.13-1.21; P<0.0001). New MI (37.0% in men, 33.1% in women; HR, 1.16; P<0.0001), ischemic stroke (21.1% versus 19.5%; HR, 1.10; P=0.004), and cardiovascular death (56.0% versus 51.1%; HR, 1.18; P<0.0001) were more frequent in men during long-term follow-up after MI. Sex differences in major adverse cardiovascular events were similar in subgroups of revascularized and non-revascularized patients, and in patients 70 to 79 and ≥80 years. Conclusions Older men had higher long-term risk of major adverse cardiovascular events after MI, compared with older women with similar baseline features and evidence-based medications. Our results highlight the importance of accounting for confounding factors when studying sex differences in cardiovascular outcomes.