Association of gender with outcomes in critically ill patients

INTRODUCTION: The influence of gender on mortality and other outcomes of critically ill patients is not clear. Different studies have been performed in various settings and patient populations often yielding conflicting results. We wanted to assess the relationship of gender and intensive care unit (ICU) outcomes in the patients included in the Acute Physiology and Chronic Health Evaluation (APACHE) IV database (Cerner Corporation, USA). METHODS: We performed a retrospective review of the data available in the APACHE IV database. A total of 261,255 consecutive patients admitted to adult ICUs in United States from 1 January 2004 to 31 December 2008 were included. Readmissions were excluded from the analysis. The primary objective of the study was to assess the relationship of gender with ICU mortality. The secondary objective was to evaluate the association of gender with active therapy, mechanical ventilation, length of stay in the ICU, readmission rate and hospital mortality. The gender-related outcomes for disease subgroups including acute coronary syndrome, coronary artery bypass graft (CABG) surgery, sepsis, trauma and chronic obstructive pulmonary disease (COPD) exacerbation were assessed as well. RESULTS: ICU mortality was 7.2% for men and 7.9% for women, odds ratio (OR) for death for women was 1.07 (95% confidence interval (CI): 1.04 to 1.1). There was a statistically significant interaction between gender and age. In patients <50 years of age, women had a reduced ICU mortality compared with men, after adjustment for acute physiology score, ethnicity, co-morbid conditions, pre-ICU length of stay, pre-ICU location and hospital teaching status (adjusted OR 0.83, 95% CI: 0.76 to 0.91). But among patients ≥50 years of age, there was no significant difference in ICU mortality between men and women (adjusted OR 1.02, 95% CI: 0.98 to 1.06). A higher proportion of men received mechanical ventilation, emergent surgery, thrombolytic therapy and CABG surgery. Men had a higher readmission rate and longer length of ICU stay. The adjusted mortality of women compared to men was higher with CABG, while it was lower with COPD exacerbation. There was no significant difference in mortality in acute coronary syndrome, sepsis and trauma. CONCLUSIONS: Among the critically ill patients, women less than 50 years of age had a lower ICU mortality compared to men, while 50 years of age or older women did not have a significant difference compared to men. Women had a higher mortality compared to men after CABG surgery and lower mortality with COPD exacerbation. There was no difference in mortality in acute coronary syndrome, sepsis or trauma.