Female Sex and Mortality in Patients with Staphylococcus aureus Bacteremia

Importance Staphylococcus aureus is the leading cause of death due to bacterial bloodstream infection. Female sex has been identified as a risk factor for mortality in S aureus bacteremia (SAB) in some studies, but not in others. Objective To determine whether female sex is associated with increased mortality risk in SAB. Data Sources MEDLINE, Embase, and Web of Science were searched from inception to April 26, 2023. Study Selection Included studies met the following criteria: (1) randomized or observational studies evaluating adults with SAB, (2) included 200 or more patients, (3) reported mortality at or before 90 days following SAB, and (4) reported mortality stratified by sex. Studies on specific subpopulations (eg, dialysis, intensive care units, cancer patients) and studies that included patients with bacteremia by various microorganisms that did not report SAB-specific data were excluded. Data Extraction and Synthesis Data extraction and quality assessment were performed by 1 reviewer and verified by a second reviewer. Risk of bias and quality were assessed with the Newcastle-Ottawa Quality Assessment Scale. Mortality data were combined as odds ratios (ORs). Main Outcome and Measures Mortality at or before 90-day following SAB, stratified by sex. Results From 5339 studies retrieved, 89 were included (132 582 patients; 50 258 female [37.9%], 82 324 male [62.1%]). Unadjusted mortality data were available from 81 studies (109 828 patients) and showed increased mortality in female patients compared with male patients (pooled OR, 1.12; 95% CI, 1.06-1.18). Adjusted mortality data accounting for additional patient characteristics and treatment variables were available from 32 studies (95 469 patients) and revealed a similarly increased mortality risk in female relative to male patients (pooled adjusted OR, 1.18; 95% CI, 1.11-1.27). No evidence of publication bias was encountered. Conclusions and Relevance In this systematic review and meta-analysis, female patients with SAB had higher mortality risk than males in both unadjusted and adjusted analyses. Further research is needed to study the potential underlying mechanisms.