Sex differences in hospital mortality following acute myocardial infarction in China: findings from a study of 45 852 patients in the COMMIT/CCS-2 study

Objective To assess the sex difference in hospital mortality following ST elevation myocardial infarction (STEMI) in China. Design Observational study of patients enrolled into a large trial, adjusting for age, presenting characteristics and hospital treatments using logistic regression. Settings 1250 hospitals in China during 1999-2005. Patients 42 683 STEMI patients, including 31 309 men and 11 374 women. Intervention In the original trial, all patients received 162 mg of aspirin plus 75 mg of clopidogrel daily or matching placebo and metoprolol (15 mg intravenous then 200 mg oral daily) or matching placebo. All other aspects of patients' treatments were at the discretion of responsible doctors. Major outcomes Hospital mortality from any cause during the scheduled trial treatment period (ie, up to 4 weeks in hospital). Results Overall, 8% of the patients died in hospital, with the crude hospital mortality being twice as high in women as in men (12.6% vs 6.3%). After adjusting for age, the sex difference in hospital mortality attenuated but remained highly significant (OR 1.54; 95% CI 1.43 to 1.66). Further adjustment for other baseline characteristics and for the treatments given in hospital had little effect on the sex difference in hospital mortality ( OR 1.50, 95% CI 1.38 to 1.62). The difference in hospital mortality was greater at a younger age, with the adjusted ORs being 2.14, 1.70, 1.48 and 1.18, respectively, for ages <55, 55-64, 65-74 and >= 75 years (p=0.0001 for trend). Conclusion Compared with men of the same age, women had approximately a 50% higher mortality following hospital admission for STEMI, with a particularly higher excess risk at age <55 years.