Sex differences in case fatality before and after admission to hospital after acute cardiac events: analysis of community based coronary heart disease register.

Abstract Objective : To determine whether the reported higher case fatality in hospital after an acute cardiac event in women can be explained by sex differences in mortality before admission and in baseline risk factors. Design : Analyses of data from a community based coronary heart disease register. Setting : Auckland region, New Zealand. Subjects : 5106 patients aged 25–64 years with an acute cardiac event leading to coronary death or definite myocardial infarction within 28 days of onset, occurring between 1986 and 1992. Main outcome measures : Case fatality before admission, 28 day case fatality for patients in hospital, and total case fatality after an acute cardiac event Results : Despite a more unfavourable risk profile women tended to have lower case fatality before admission than men (crude odds ratio 0.88; 95% confidence interval 0.77 to 1.02). Adjustment for age, living arrangements, smoking, medical history, and treatment increased the effect of sex (0.72; 0.60 to 0.86). After admission to hospital, women had a higher case fatality than men (1.76; 1.43 to 2.17), but after adjustment for confounders this was reduced to 1.18 (0.89 to 1.58). Total case fatality 28 days after an acute cardiac event showed no significant difference between men and women (0.85; 0.70 to 1.02). Conclusions : The higher case fatality after an acute cardiac event in women admitted to hospital is largely explained by differences in living status, history, and medical treatment and is balanced by a lower case fatality before admission. Key messages Data from a community based coronary heart disease register were used to examine sex differences in case fatality before and after admission Women had a higher case fatality after admission but a lower case fatality before admission Total case fatality 28 days after an acute cardiac event showed no significant difference between men and women The higher case fatality after an acute cardiac event in women admitted to hospital is largely explained by confounding