Gender differences in the outcome of community-acquired Staphylococcus aureus bacteraemia: A historical population-based cohort study

OBJECTIVES: Female gender has been suggested to be associated with poor outcome in patients with Staphylococcus aureus bacteraemia (SAB), but existing data remain sparse and conflicting. We investigated clinical outcomes in female and male patients with community-acquired (CA) SAB.

METHODS: We used population-based medical registers to conduct a cohort study of all adult patients with CA-SAB in Northern Denmark, 2000-2011. Thirty-day mortality after CA-SAB for female and male patients was estimated by the Kaplan-Meier method. Using Cox proportional hazards regression, we computed hazard ratios (HRs) of death according to gender, overall and stratified by age groups, comorbidity level, and selected major diseases while adjusting for potential confounders. Moreover, we estimated 30-day prevalence proportions for SAB-associated infective endocarditis and osteomyelitis by gender.

RESULTS: Among 2,638 patients with CA-SAB, 1,022 (39%) were female. Thirty-day mortality was 29% (n=297) in female patients and 22% (n=355) in male patients, yielding an adjusted HR (aHR) of 1.30 (95% confidence interval (CI), 1.11-1.53)).This association appeared robust across age groups, whereas no consistent pattern was observed according to comorbidity level. Compared to males, the prognostic impact of gender was most pronounced among female patients with diabetes (aHR=1.52 (95% CI, 1.04-2.21)), and among female patients with cancer (aHR=1.40 (95% CI, 1.04-1.90)). The 30-day prevalence of infective endocarditis or osteomyelitis did not differ according to gender.

CONCLUSION: Female patients with CA-SAB experienced increased 30-day mortality compared with male patients. Gender should be considered in the triage and risk stratification of CA-SAB patients.