Variations in Quality of Care by Sex and Social Determinants of Health among Younger Adults with Acute Myocardial Infarction in the US and Canada

Importance: Quality of care of young adults with acute myocardial infarction (AMI) may depend on health care systems in addition to individual-level factors such as biological sex and social determinants of health (SDOH). Objective: To examine whether the quality of in-hospital and postacute care among young adults with AMI differs between the US and Canada and whether female sex and adverse SDOH are associated with a low quality of care. Design, Setting, and Participants: This retrospective cohort analysis used data from 2 large cohorts of young adults (aged ≤55 years) receiving in-hospital and outpatient care for AMI at 127 centers in the US and Canada. Data were collected from August 21, 2008, to April 30, 2013, and analyzed from July 12, 2019, to March 10, 2021. Exposures: Sex, SDOH, and health care system. Main Outcomes and Measures: Opportunity-based quality-of-care score (QCS), determined by dividing the total number of quality indicators of care received by the total number for which the patient was eligible, with low quality of care defined as the lowest tertile of the QCS. Results: A total of 4048 adults with AMI (2345 women [57.9%]; median age, 49 [interquartile range, 44-52] years; 3004 [74.2%] in the US) were included in the analysis. Of 3416 patients with in-hospital QCS available, 1061 (31.1%) received a low QCS, including more women compared with men (725 of 2007 [36.1%] vs 336 of 1409 [23.8%]; P <.001) and more patients treated in the US vs Canada (962 of 2646 [36.4%] vs 99 of 770 [12.9%]; P <.001). Conversely, low quality of post-AMI care (748 of 2938 [25.5%]) was similarly observed for both sexes, with a higher prevalence in the US (678 of 2346 [28.9%] vs 70 of 592 [11.8%]). In adjusted analyses, female sex was not associated with low QCS for in-hospital (odds ratio [OR], 1.05; 95% CI, 0.87-1.28) and post-AMI (OR, 1.07; 95% CI, 0.88-1.30) care. Conversely, being treated in the US was associated with low in-hospital (OR, 2.93; 95% CI, 2.16-3.99) and post-AMI (OR, 2.67; 95% CI, 1.97-3.63) QCS, regardless of sex. Of all SDOH, only employment was associated with higher quality of in-hospital care (OR, 0.72; 95% CI, 0.59-0.88). Finally, only in the US, low quality of in-hospital care was associated with a higher 1-year cardiac readmissions rate (234 of 962 [24.3%]). Conclusions and Relevance: These findings suggest that beyond sex, health care systems and SDOH that depict social vulnerability are associated with quality of AMI care. Taking into account SDOH among young adults with AMI may improve quality of care and reduce readmissions, especially in the US.