Factors Affecting Mortality and a Mortality Scoring System in Patients with Staphylococcus aureus Bloodstream Infection

Introduction: Staphylococcus aureus bloodstream infection (SA-BSI) is associated with a high mortality rate despite appropriate treat-ment. The ability to predict the risk of mortality in SA-BSI may have a major impact on guiding clinical decisions and managing the patient's risk. The purpose of this study is to determine risk factors for mortality in patients with SA-BSI. A scoring system predicting mortality on the basis of these risk factors was also established. Materials and Methods: This retrospective study involved patients diagnosed with SA-BSI and admitted for treatment to the intensive care unit or clinics. Patients' clinical, laboratory, and treatment details were retrieved from file records in the hospital electronic data management system, from consultation notes, from infectious disease patient follow-up cards, and infection control committee data. Statistical analysis was performed on IBM SPSS version 23.0 software, and p values< 0.05 were regarded as significant.Results: Three hundred nine patients were included in the study, 183 (59.2%) men and 126 (40.8%) women, with a mean age of 62.8 +/- 15.9 years. Two hundred eleven (68.3%) patients survived, and 98 (31.7%) died. Admission to the intensive care unit, the Charlson comorbidity index, body temperature, impaired general condition, hypotension, and initiation of appropriate antibiotherapy with in the first 24 h were identified as independent predictors of mortality. Three mortality scores were established based on laboratory and clinical parameters at time of diagnosis, and on the third and fifth days of treatment. The laboratory parameters employed included procalcitonin, C-reactive protein, albumin, white blood cell count, platelet count, and erythrocyte distribution width. The clinical parameters included hypotension, body temperature, and the Charlson comorbidity index. A score exceeding 9 on mortality score 3 was found to predict mortality with 78.6% sensitivity and 73.5% specificity.Conclusion: SA-BSI is an important cause of mortality in hospitalized patients, and the clinical outcomes of this infection can be accu-rately predicted with various clinical and laboratory parameters.