Age-specific gender differences in early mortality following ST-segment elevation myocardial infarction in China
Zheng X, Dreyer RP, China PEACE Collaborative Group.

KEYWORDS
Coronary heart disease; risk prediction

OBJECTIVE - To assess whether younger, but not older, women in China have higher in-hospital mortality following ST-Segment Elevation Myocardial Infarction (STEMI) compared with men, and whether this relationship varied over the last decade or across rural/urban areas.

METHODS - We analysed a nationally representative sample of 11 986 patients with STEMI from 162 Chinese hospitals in 2001, 2006 and 2011, in the China PEACE-Retrospective AMI Study and compared in-hospital mortality between women and men with gender-age interactions in multivariable models.

RESULTS - The overall in-hospital mortality rate was higher in women compared with men (17.2% vs 9.1%, p<0.0001; unadjusted OR 2.07, 95% CI 1.85 to 2.33). The unadjusted OR for mortality in women, compared with men, was 2.20 (95% CI 1.59 to 3.04), 2.21 (95% CI 1.74 to 2.79), 1.37 (95% CI 1.15 to 1.65) and 1.25 (95% CI 0.97 to 1.63) for ages <60, 60-69, 70-79 and ≥80 years, respectively. After adjustment for patient characteristics, hospital characteristics and year of study, the OR for mortality comparing women with men was 1.69 (95% CI 1.01 to 2.83), 1.64 (95% CI 1.24 to 2.19), 1.15 (95% CI 0.90 to 1.46) and 0.82 (95% CI 0.60 to 1.11) for ages <60, 60-69, 70-79 and ≥80 years, respectively. The gender-age interaction for mortality was statistically significant (p=0.009), even after adjustment for a wide range of confounders, and did not vary over time or across rural/urban areas.

CONCLUSIONS - Among a Chinese population with STEMI, gender differences in early mortality were age-dependent and greatest in the younger groups <70 years of age.

TRIAL REGISTRATION NUMBER - http://www.clinicaltrials.gov (NCT01624883).