Background: Existing data on female sex and excess cardiovascular mortality after myocardial infarction (MI) mostly come from high-income countries (HICs). This study aimed to investigate how sex disparities in treatments and outcomes vary across countries with different income levels.
Methods: Data from the ISACS-Archives registry included 22 087 MI patients from 6 HICs and 6 middle-income countries (MICs). MI data were disaggregated by clinical presentation: ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI). The primary outcome was 30-day mortality.
Results: Among STEMI patients, women in MICs had nearly double the 30-day mortality rate of men (12.4% versus 5.8%; adjusted risk ratio [RR] 2.30, 95% CI 1.98-2.68). This difference was less pronounced in HICs (6.8% versus 5.1%; RR 1.36, 95% CI 1.05-1.75). Despite more frequent treatments and timely revascularization in MICs, sex-based mortality differences persisted even after revascularization (8.0% versus 4.1%; RR 2.05, 95% CI, 1.68-2.50 in MICs and 5.6% versus 2.6%; RR 2.17, 95% CI 1.48-3.18) in HICs. Additionally, women from MICs had higher diabetes rates compared to HICs (31.8% versus 25.1%, standardized difference = 0.15). NSTEMI outcomes were relatively similar between sexes and income groups.
Conclusions: Sex disparities in mortality rates following STEMI are more pronounced in MICs compared to HICs. These disparities cannot be solely attributed to sex-related inequities in revascularization. Variations in mortality may also be influenced by sex differences in socioeconomic factors and baseline comorbidities.
Keywords: Myocardial infarction; Outcomes; Sex differences; middle-income countries.
© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.