The effect of early diuretics administration on acute kidney injury progression after cardiac surgery: a post-hoc analysis of a multicenter retrospective cohort study (BROTHER study)

Positive fluid balance is associated with acute kidney injury (AKI) following cardiac surgery in a dose-dependent manner. Although diuresis is a common intervention for fluid overload, the optimal timing of diuretic administration for preventing AKI after cardiac surgery remains unclear. We aimed to investigate whether early administration of diuretics after cardiac surgery is associated with subsequent AKI progression. This was a post-hoc analysis of a multicenter retrospective cohort study that included adult patients admitted to 14 intensive care units (ICUs) after elective cardiac surgery between January and December 2018. The exposure variable was the administration of intravenous diuretics during the initial 24 hours after ICU admission. The primary outcome was AKI progression, defined as one or more AKI stages using Kidney Disease: Improving Global Outcomes creatinine and urine output criteria between 24 and 72 hours compared with the worst stage during the first 24 hours. We used multivariable logistic regression analyses to assess the association between early administration of diuretics and AKI progression. Among the 718 patients analyzed, 335 (47%) received intravenous diuretics within the first 24 hours, and AKI progression occurred in 115 patients (16%). In the multivariable analyses, early diuresis was not associated with AKI progression (odds ratio, 1.12; 95% confidence interval, 0.74–1.69), confirmed by sensitivity analyses. Early administration of intravenous diuretics was not associated with a lower risk of AKI progression after cardiac surgery.