Acute kidney injury in Staphylococcus aureus bacteraemia: a recurrent events analysis

ObjectivesTo estimate risk factors for AKI and the effect of AKI on mortality in Staphylococcus aureus bacteremia, while taking into account recurrent AKI episodes, competing risks, time-varying variables and time-varying effects.MethodsWe performed an unplanned analysis using data from a multicenter cohort study of patients with SAB. Primary outcome was cumulative incidence of AKI, according to KDIGO definitions.ResultsWe included 453 patients in this study of whom 194 (43%) patients experienced one or more AKI episodes. Age (HR 1.013, 95% CI 1.001 – 1.024), Charlson comorbidity index (HR 1.07, 95% CI 1.01 - 1.14), prior chronic kidney disease (HR 1.76, 95% CI 1.28 – 2.42), septic shock (HR 3.28, 95% CI 2.31 – 4.66), persistent bacteremia (HR 1.53, 95% CI 1.08 – 2.17) and vancomycin therapy (HR 1.80, 95% CI 1.05 – 3.09) were independently associated with AKI, but flucloxacillin, cefazolin, rifampicin and aminoglycoside therapy were not. After adjustment for confounders and immortal time bias, AKI was associated with an increased risk of 90-day mortality (HR 4.26, 95% CI 2.91 – 6.23).ConclusionsIncidence of AKI in SAB is high and a substantial proportion of patients develops recurrent episodes of AKI after recovery. AKI is specifically linked to the use of vancomycin and not to anti-staphylococcal penicillins. Clinical outcome of patients with SAB complicated by AKI is worse than previously estimated.