Low-Dose Continuous Kidney Replacement Therapy and Mortality in Critically Ill Patients With Acute Kidney Injury: A Retrospective Cohort Study

Abstract

Rationale & ObjectiveContinuous kidney replacement therapy (CKRT) is preferred when available for hemodynamically unstable acute kidney injury (AKI) patients in the intensive care unit (ICU). The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend a delivered CKRT dose of 20–25 mL/kg/h, however in Japan, doses are typically below this recommendation due to government health insurance system restrictions. This study investigated the association between mortality and dose of CKRT. Study DesignSingle-center retrospective cohort study. Setting& Participants: Critically ill patients with AKI treated with CKRT at a tertiary Japanese university hospital between January 1, 2012, and December 31, 2021. ExposureDelivered CKRT doses below or above the median. Outcome90-day mortality after CKRT initiation. Analytical ApproachMultivariable Cox regression analysis and Kaplan–Meier analysis. ResultsThe study population consisted of 494 patients. The median age was 72 years, and 309 patients (62.6%) were men. Acute tubular injury was the leading cause of AKI, accounting for 81.8%. The median delivered CKRT dose was 13.2 mL/kg/h. 456 (92.3%) study participants received delivered CKRT doses below 20 mL/kg/h, and 204 (41.3%) died within 90 days after CKRT initiation. Multivariable Cox regression analysis revealed increased mortality in the below-median group (hazard ratio: 1.73, 95% confidence interval: 1.19–2.51, P = 0.004). Additionally, a significant, inverse, non-linear association between 90-day mortality and delivered CKRT dose was observed using delivered CKRT dose as a continuous variable. LimitationsSingle-center, retrospective, observational study. ConclusionsA lower delivered CKRT dose was independently associated with higher 90-day mortality among critically ill patients who mostly received dosing below current KDIGO recommendations.