The optimal timing of continuous renal replacement therapy according to the modified rifle classification in critically ill patients with acute kidney injury: A retrospective observational study

Abstract

Background: Acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT) is associated with high mortality in critically ill patients. However, the optimal timing to initiate CRRT in patients with AKI is unknown. The purpose of this study is to investigate whether the timing of initiation of CRRT according to severity of AKI is associated with in-hospital mortality. Methods: We retrospectively reviewed 189 patients treated with CRRT for AKI in the intensive care unit between January 2009 and February 2013. Patients aged <18 years or receiving renal replacement therapy for end-stage renal disease were excluded. The modified RIFLE classification was used to stratify patients into two groups at initiation of CRRT, including early (no AKI or risk) and late (injury or failure). Results: There were 52 (28%) patients in the early group and 137 (72%) patients in the late group. The median age was 72 (range 61-78) years, including 70% males. The median intensive care unit and hospital stays were 10 (4-18) and 26 (13-58) days, respectively. Crude early vs. late group intensive care unit mortality was 50 vs. 44% (P = 0.51), and in-hospital mortality was 64 vs. 50% (P = 0.10), respectively. Logistic regression analysis showed that late initiation (OR, 0.30; 95% CI, 0.13-0.71; P = 0.006) and lower SAPS score (OR, 1.04; 95% CI, 1.02-1.06; P < 0.001) were independently associated with decreased mortality. Conclusions: This study suggests that late initiation of CRRT is associated with a lower risk of in-hospital mortality in patients with AKI. Further studies are needed to confirm the optimal timing for initiation of CRRT.