Sex differences in illness severity and mortality among adult intensive care patients: A systematic review and meta-analysis

Purpose: To investigate the association between sex and illness severity and mortality of ICU patients. Methods: We performed systematic searches of MEDLINE and EMBASE for observational studies of adult ICU pa-tients that explicitly examined the association between sex and illness severity or mortality. We used a random effects model to calculate standardised mean differences in illness severity scores and pooled odds ratios for mor-tality of women compared to men. Results: We identified 21 studies with 505,138 participants in total (43.1% women). There was substantial hetero-geneity among studies. Only two studies were at low risk of bias overall. At ICU admission, there was a pattern of higher illness severity scores among women (standardised mean difference 0.04, 95% CI-0.01-0.09). Women had higher risk-adjusted mortality than men at ICU discharge (OR 1.25 95% CI 1.03-1.50) and 1 year (OR 1.08, 95% CI 1.02-1.13), however this finding was not robust to sensitivity analysis. Conclusions: Women tend to have higher illness severity scores at ICU admission. Women also appear to have higher risk-adjusted mortality than men at ICU discharge and at 1 year. Given the heterogeneity and risk of bias in the existing literature, additional studies are needed to confirm or refute these findings. (c) 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).