Effect of patient sex on intensive care unit survival

Human observations have shown different mortality rates between men and women with various pathological conditions, but this issue has not been widely studied in a heterogeneous population of critically ill patients.

Retrospective analysis of all patients admitted to a mixed medical-surgical, 31-bed intensive care unit (ICU) during 2 different years (1983 and 1995) to evaluate possible differences in mortality between male and female patients and between medical and surgical admissions and variations in these differences over time.

From a total of 4420 admissions (1587 women, 2833 men), women showed a higher mortality, with an odds ratio (OR) of 1.18 (95% confidence interval [CI], 1.02-1.38). This pattern was the same for the 2 periods, and all patient data were therefore analyzed together. After age stratification, the differences were significant for female patients older than 50 years (OR, 1.33; 95% CI, 1.12-1.58) but not in the younger age group. The subgroup of medical admissions had a higher mortality (24.4% vs 7.4%, P<.001) and a higher female proportion (37.9% vs 34.2%, P =.01) than surgical admissions. In multivariate analysis, female sex remained an important predictor of mortality (OR, 1.54; 95% CI, 1.25-1.89). Women had a higher mortality than men in the subgroup of cardiovascular diseases. The highest mortality in female patients was present in the first days after admission and decreased over time, showing a covariance of time and sex.

In a mixed medical-surgical ICU, older women have a higher mortality rate than men. This difference is not apparent for patients staying longer in the ICU.