Acute myocardial infarction in women: Contribution of treatment variables to adverse outcome

Background Women have excessive mortality rates after acute myocardial infarction compared with men. The extent to which this increased risk can be attributed to differences in treatment is not well-understood. Methods This was an observational follow-up study of 1737 patients admitted with acute myocardial infarction for coronary care between January 1, 1988, and December 31, 1997. Results Compared with men,women took longer to arrive at the hospital (132.5 minutes [range 76 to 291 minutes] vs 120 minutes [range 60 to 240 minutes]; P =.006), were less likely to receive aspirin acutely [87.8% vs 91.3%; P =.03], had longer door-to-needle times (90 minutes [range 60 to 143.5 minutes] vs 78 minutes [range 50 to 131 minutes]; P =.004), and were less likely to be given beta -blockers at hospital discharge (31.6% vs 44.9%; P<.0001). Estimated survival [95% confidence interval [CI]) at 30 days was only 78.4% [range 74.4% to 81.9%) for women compared with 88.0% (range 86.1% to 89.7%) for men. Women were older and more often white, but their excess risk (hazard ratio 2.09; 95% CI, 1.59-2.75) persisted offer adjustment for age, racial group, and diabetes (hazard ratio 1.52; 95% CI, 1.15-2.01). Additional adjustment for emergency thrombolytic and aspirin therapy caused a further small reduction in the excess risk for women (hazard ratio 1.46, 95% Ct, 1.09-1.98, but with adjustment for aspirin and P-blockers prescribed at discharge, the excess risk attributable to being female disappeared as the hazard ratio fell to 0.75 (95% Cl, 0.31-1.84). Estimated 30-day survival free of reinfarction and unstable angina was also lower for women than for men (75% [range 77% to 79%] vs 86% [range 84% to 88%]); again, the excess risk for women persisted despite adjustment for age and racial group before disappearing as treatment variables were introduced into the model. The influence of treatment Variables on the differential risks for women and men disappeared at 12 months. Conclusions This study has shown that women with acute myocardial infarction arrived later at the hospital, were less likely to be given aspirin therapy acutely, had longer door-to-needle times, and, on discharge from the hospital, were less likely to be prescribed <beta>-blockers for secondary prevention. The data suggest that the failure to treat women as vigorously as men mode a significant contribution to their worse outcome.