Sex differences in survival after myocardial infarction in Sweden - Data from the Swedish National Acute Myocardial Infarction Register

Aims Women, particularly younger women, hospitalized with acute myocardial infarction have been found to have poorer prognosis than men. A large propo rtion of deaths due to myocardial infarction. however. occur in the prehosp ital phase. We set out to analyse age-specific sex differences in survival after myocardial infarction at different time intervals from the onset of a cute myocardial infarction, including pre-hospital deaths and 1-year overal l survival. Methods and Results The National Acute Myocardial Infarction Register in Sw eden was used to analyse age-specific sex differences in mortality outside hospital. 28-day mortality and 1-year mortality in 353 905 cases occurring between 1987 and 1995 in Swedish men and women aged 30 to 89 years. Overall . one in four of all myocardial infarction victims died outside hospital. A t all ages, except in individuals younger than 50 years. men had higher pre -hospital mortality. The odds of dying within 28 days for women below 50 ye ars of age, compared to men, was 1.84 (1.56-2.18) in hospitalized patients and 1.31 (1.18-1.46) in all infarction patients. Above the age of 65, in th e total population with myocardial infarction, women had a better prognosis , with odds ratios ranging from 0.83 to 0.89. In patients surviving the fir st 28 days, 4.0% of the women and 2.9% of the men below the age of 50 were dead within a year after the infarction. odds ratio 1.37 (1.06-1.76). This excess mortality was mainly due to diabetes and noncardiac causes. Only wom en younger than 50 years had a significantly poorer overall 1-year survival than men of the same age. At the age of 70 or more, women had a small surv ival advantage. Conclusion In the total acute myocardial infarction population. only women under 50 years of age have a consistently worse prognosis than men. Much of the excess mortality in young women seems to be associated with diabetes. (Eur Heart J 2001; 22: 314-322, doi:10.1053/euhj.2000.2368) (C) 2001 The Eu ropean Society of Cardiology.