Risk and prognosis of Staphylococcus aureus bacteremia among individuals with and without end-stage renal disease: a Danish, population-based cohort study

BACKGROUND Staphylococcus aureus is a leading cause of bloodstream infections among hemodialysis patients and of exit-site infections among peritoneal dialysis patients. However, the risk and prognosis of Staphylococcus aureus bacteremia among end-stage renal disease patients have not been delineated. METHODS In this Danish nationwide, population-based cohort study patients with end-stage renal disease and matched population controls were observed from end-stage renal disease diagnosis/sampling until first episode of Staphylococcus aureus bacteremia, death, or end of study period. Staphylococcus aureus positive blood cultures, hospitalization, comorbidity, and case fatality were obtained from nationwide microbiological, clinical, and administrative databases. Incidence rates and risk factors were assessed by regression analysis. RESULTS The incidence rate of Staphylococcus aureus bacteremia was very high for end-stage renal disease patients (35.7 per 1,000 person-years; 95% CI, 33.8-37.6) compared to population controls (0.5 per 1,000 person-years; 95% CI, 0.5-0.6), yielding a relative risk of 65.1 (95% CI, 59.6-71.2) which fell to 28.6 (95% CI, 23.3-35.3) after adjustment for sex, age, and comorbidity. After stratification for type of renal replacement therapy, we found the highest incidence rate of Staphylococcus aureus bacteremia among hemodialysis patients (46.3 per 1,000 person-years) compared to peritoneal dialysis patients (22.0 per 1,000 person-years) and renal transplant recipients (8.9 per 1,000 person-years). In persons with Staphylococcus aureus bacteremia, ninety-day case fatality was 18.2% (95% CI, 16.2%-20.3%) for end-stage renal disease patients and 33.7% (95% CI, 30.3-37.3) for population controls. CONCLUSIONS Patients with end-stage renal disease, and hemodialysis patients in particular, have greatly increased risk of Staphylococcus aureus bacteremia compared to population controls. Future challenges will be to develop strategies to reduce Staphylococcus aureus bacteremia-related morbidity and death in this high-risk population.