[Effect of early initiation of continuous renal replacement therapy based on the KDIGO classification on the prognosis of critically ill patients with acute kidney injury].

Objective: To investigate the impact of early initiation of continuous renal replacement therapy (CRRT) based on "Kidney Disease: Improving Global Outcomes (KDIGO)" classification on the prognosis of critically ill patients with acute kidney injury (AKI).

Methods: A retrospective analysis of clinical data of patients diagnosed as AKI in Department of Critical Care Medicine of Zhejiang Provincial People's Hospital from January 2011 to January 2015 was conducted. All patients included should be 18 years old or older, having stayed in intensive care unit (ICU) for more than 48 hours, and received CRRT. All subjects were divided into three groups according to their renal function before CRRT according to the KDIGO-AKI guideline: AKI-stage 1 group, AKI-stage 2 group and AKI-stage 3 group. The general condition, original disease, severity of disease, duration of mechanical ventilation, the length of ICU or hospital stay, 28-day survival rate and in-hospital mortality rate were compared among these three groups. Additionally, risk factors for the 28-day survival rate and hospital mortality of critically ill patients with AKI were screened by logistic regression analysis.

Results: A total of 258 critically ill patients with AKI were enrolled, with 64 cases in AKI-stage 1 group, 62 cases in AKI-stage 2 group, and 132 cases in AKI-stage 3 group. 116 patients survived with 28-day survival rate of 44.96%. 154 patients died with hospital mortality 59.69%. The precipitating factors of AKI in all three groups (stage 1, stage 2, and stage 3) were similar, with sepsis, heart failure and poisoning (drugs or poison) being the main triggers for AKI, accounting for 35.66%, 19.38% and 13.18%, respectively. There were significant differences in the rate of vasoactive agent usage (31.25%, 41.94%, 50.00%, χ2 = 6.241, P = 0.044), acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score (20.87±7.37, 17.19±7.02, 22.58±7.95, F = 5.292, P = 0.006) and sequential organ failure assessment (SOFA) score (8.41±3.46, 6.22±2.43, 9.58±3.71, F = 10.328, P = 0.000), while there was no significant difference in gender, age, primary disease, time from ICU admission to the beginning of CRRT, mean arterial pressure (MAP), lactate level or 24-hour lactate clearance rate (LCR), mechanical ventilation time, the length of ICU or hospital stay, 28-day survival rate or hospital mortality among these three groups (all P > 0.05). According to the logistic regression analysis, time from ICU admission to start of CRRT and lactate level were the independent risk factors for 28-day survival rate or hospital mortality of critically ill patients with AKI [odds ratio (OR) for 28-day survival rate was 0.850 and 0.774, 95% confidence interval (95%CI) was 0.752-0.960 and 0.638-0.940, P value was 0.009 and 0.010, respectively; OR for hospital mortality was 0.884 and 0.756, 95%CI was 0.781-1.000 and 0.610-0.939, P value was 0.049 and 0.011, respectively].

Conclusion: Early initiation of CRRT based on KDIGO-AKI classification could not improve the prognosis of critically ill patients with AKI, the optimal timing of RRT for such patients remains to be further explored.