Clinical and laboratory predictors of mortality in Staphylococcus aureus bacteremia

This study aimed to describe the epidemiological and clinical features of patients admitted to non-intensive care hospital wards due to Staphylococcus aureus bacteremia (SAB) and to identify predictors of mortality to improve patient outcomes. This single-center retrospective study included hospitalized patients with SAB between 2016 and 2024. We retrieved clinical and microbiological data retrospectively from the electronic medical record system. The research comprised 356 patients with SAB. The 30-day and in-hospital mortality rates were 7.3% (n = 26) and 9.8% (n = 35), respectively. The multivariate analysis revealed neutrophil-to-lymphocyte ratio (NLR) (HR = 1.08; 95% CI = 1.02-1.13; p = 0.002), CRP (HR = 1.01; 95% CI = 1-1.02 ; p = 0.04), and albumin (HR = 0.83; 95% CI = 0.73-0.95; p = 0.008) as predictors for 30-day mortality. Pneumonia (HR = 15.03; 95% CI = 2.05-109.71; p = 0.008), leukemia (HR = 28.72; 95% CI = 1.56-525.92; p = 0.002), and sepsis (HR = 7.06; 95% CI = 1.02-48.53; p = 0.002) were identified as significant risk factors for mortality. Using the Cox regression analysis, age (HR: 1.05, CI:1.01-1.10, p = 0.01), leukemia (HR: 0.80, CI:0.71-0.90, p < 0.001), and low albumin level (HR: 11.76; CI:1.76-78.42, p = 0.01) were identified as independent risk factors affecting in-hospital mortality. We used the receiver operating characteristic (ROC) curve to predict the30-day mortality. The area under the ROC curve values were 0.619 (p = 0.044) for NLR, 0.692 (p = 0.001) for CRP, and 0.791 (p < 0.001) for albumin. The highest sensitivity and specificity at 30-day mortality were obtained from CRP and albumin, with a sensitivity of 65.4% and a specificity of 78.5% for albumin. Elevated NLR and CRP levels, along with decreased albumin levels, may predict poor clinical outcomes and could assist clinicians in optimizing the management of this bacterial infection. As a result, early diagnosis and appropriate antibiotic treatments are crucial in reducing mortality in SAB.