Aims: This study examined clinical factors associated with sex differences in the use of acute reperfusion therapy (fibrinolysis or primary percutaneous coronary intervention) in ST-elevation myocardial infarction (STEMI) patients, and the interaction between sex and these factors in Sweden and Canada. Methods: Patients with STEMI in Sweden (n=32,676 from the Register of Information and Knowledge about Swedish Heart Intensive Care Admissions) were compared with similar patients in Canada (n=3375 from the Canadian Global Registry of Acute Coronary Events) for the period 2004–2008. Results: Unadjusted vs. age-adjusted odds ratios (OR) for no reperfusion (women vs. men) were for Sweden 1.57 (95% CI 1.49–1.64) vs. 1.14 (95% CI 1.08–1.20), and for Canada 1.61 (95% CI 1.39–1.87) vs. OR 1.18 (95% CI 1.01–1.39). Sex differences persisted after multivariable adjustments (including prehospital delay, atypical symptoms, diabetes), factors for which no interaction with sex was found. Among women <60 >years, adjusting for atypical symptoms in Canada and angiographic data in Sweden made the greatest contribution to explaining observed sex differences. Conclusions: In both countries, acute reperfusion therapy in STEMI was used less often in women than in men. Factors associated with these sex differences appear to differ between older and younger women. Targeted interventions are needed to optimize care for women with STEMI, as well as sex- and age-stratified reporting of quality indicators to assess their effectiveness.

BACKGROUND: The question of whether gender-related disparities still exist in the treatment and outcomes of patients presenting with acute coronary syndromes (ACS) remains controversial. Using data from 4 registries spanning a decade, we sought to determine whether sex-related differences have persisted over time and to examine the treating physician's rationale for adopting a conservative management strategy in women compared with men. METHODS: From 1999 to 2008, 14,196 Canadian patients with non-ST-segment elevation ACS were recruited into the Acute Coronary Syndrome I (ACSI), ACSII, Global Registry of Acute Coronary Events (GRACE/GRACE(2)), and Canadian Registry of Acute Coronary Events (CANRACE) prospective multicenter registries. RESULTS: Women in the study population were found to be significantly older than men and were more likely to have a history of heart failure, diabetes, or hypertension. Fewer women were treated with thienopyridines, heparin, and glycoprotein IIb/IIIa inhibitors compared with men in GRACE and CANRACE. Female gender was independently associated with a lower in-hospital use of coronary angiography (adjusted odds ratio 0.76, 95% CI 0.69-0.84, P < .001) and higher in-hospital mortality (adjusted odds ratio 1.26, 95% CI 1.02-1.56, P = .036), irrespective of age (P for interaction =.76). Underestimation of patient risk was the most common reason for not pursuing an invasive strategy in both men and women. CONCLUSIONS: Despite temporal increases in the use of invasive cardiac procedures, women with ACS are still more likely to be treated conservatively, which may be due to underestimation of patient risk. Furthermore, they have worse in-hospital outcomes. Greater awareness of this paradox may assist in bridging the gap between current guidelines and management practices.