Mortality in Staphylococcus aureus bacteraemia remains high despite adherence to quality indicators: secondary analysis of a prospective cohort study

Objectives: To evaluate the association between compliance with previously published quality indicators (QIs) for the management of Staphylococcus aureus bacteraemia (SAB) and 30-day mortality.

Methods: We conducted a post hoc analysis of all adult patients with SAB who were hospitalized at a Spanish university hospital between 2013 and 2018. We evaluated the compliance with 7 QIs of SAB management (i.e., Infectious Diseases consultation, follow-up blood cultures, early source control, echocardiography, early cloxacillin or cefazolin, vancomycin monitoring, and appropriate treatment duration). The QIs compliance rate was considered good if ≥75% of the QIs recommended in each patient were performed. We studied the impact of different risk factors (including QIs compliance) on 30-day all-cause mortality adjusting by multivariable modeling and propensity-matched analysis.

Results: We included 441 patients with SAB. The QIs compliance rate was ≥75% in 361 patients (81.9%). A total of 95 patients (21.5%) died within 30 days after the index blood culture. In the multivariable model, the variables associated with 30-day mortality were: age (OR, 1.1; 95% CI, 1.0-1.1), Charlson comorbidity index (OR, 1.2; 95% CI, 1.1-1.4), persistent bacteraemia >72 h (OR, 6.0; 95% CI, 3.2-11.5), infective endocarditis (OR, 2.8; 95% CI, 1.2-6.7), and SAB of unknown source (OR, 3.3; 95% CI, 1.5-7.1). We did not find an association between a global QIs compliance rate of ≥75% or any individual QI with 30-day mortality.

Conclusions: SAB 30-day mortality remains high despite good adherence to previously published QIs for the management of SAB. Future research should focus on additional factors to further improve SAB-related mortality.