Predictive and prognostic value of RIFLE classification on ICU Patients with acute kidney injury treated with continuous renal replacement therapy

Background: The optimal timing to start continuous renal replacement therapy (CRRT) for acute kidney injury (AKI) in critically ill ICU patients has not been accurately detected. The recently proposed risk, injury, failure, loss, end-stage kidney disease (RIFLE) criteria for diagnosis of AKI may provide a method for nephrologists to decide the “optimal timing” for starting dialysis. Objective: our study aimed: (1) to analyze the correlation between RIFLE stages at the start of CRRT and 90-day survival rate after CRRT start, (2) to further analyze the correlation of RIFLE stage with the malignant kidney outcome in the 90-day survivors, and (3) to determine the effect of the timing of CRRT on the 90-day survival and malignant kidney outcome in 90-day survivors. Methods: A retrospective cohort analysis was performed on the data of 96 critically ill patients in ICU, CCU, and CICU with AKI, treated with CRRT during a 1-year period in MOH hospital, makkah, Saudi Arabia from November 2011 to November 2012. Information such as age, sex, RIFLE stage, sepsis, sepsis-related organ failure assessment (SOFA) score, and number of organ failures before CRRT, CRRT time, survival, and kidney outcome conditions at 90 days after CRRT start was collected. According to their baseline severity of AKI at the start of CRRT, the patients were assigned to three groups according to the increasing severity of RIFLE stages: RIFLE-R (risk of renal dysfunction, R), RIFLE-I (injury to the kidney, I) and RIFLE-F (failure of kidney function, F) using RIFLE criteria. The malignant kidney outcome was classified as RIFLE-L (loss of kidney function, L) or RIFLE-E (end-stage kidney disease, E) using RIFLE criteria. The correlation between RIFLE stage and 90-day survival rate was analyzed among these three RIFLE-categorized groups. Additionally, the association between RIFLE stage and the malignant kidney outcome (RIFLE-L+RIFLF-E) in the 90-day survivors was analyzed. Results: forty eight of the overall 96 patients survived to 90 days after the start of CRRT. There were 14, 20 and 62 patients in RIFLE-R, RIFLE-I and RIFLE-F groups respectively with corresponding 90-day survival rate of 78.5 % (11/14), 60 % (12/20) and 40.3 % (25/62) (P <0.01, compared among groups). The percentage of the malignant kidney outcome of 90-day survivors in the RIFLE-R, RIFLE-I, and RIFLE-F groups was 18.18 % (2/11), 25 % (3/12) and 56 % (14/25), respectively (P <0.01). After adjustment for other baseline risk factors, the relative risk (RR) for the 90-day mortality significantly increased with baseline RIFLE stage. Patients in RIFLE-F had a higher RR of 1.96 (95% confidence interval (CI): 1.06–3.62) than patients in RIFLE-I (RR: 1.09, 95% CI: 0.55–2.15) compared with patients in RIFLE-R (P for trend <0.01). Similarly, baseline RIFLE stage also significantly correlated with the odds ratio (OR) for the malignant kidney outcome in 90-day survivors (P <0.05). Ninety-day survivors in the RIFLE-F group had a borderline significantly highest OR of 6.88 (95% CI: 0.85–55.67). Conclusions: The RIFLE classification may be used to predict 90-day survival after starting CRRT and the malignant kidney outcome of 90-day survivors in the critically ill patients with AKI treated with CRRT. Early versus late initiation of dialysis prior to RIFLE-F stage may be the optimal timing. [Walid M Afifi, Haitham E Mohamed, Mohamed Abdelzaher. Predictive and prognostic value of RIFLE classification on ICU Patients with acute kidney injury treated with continuous renal replacement therapy. J Am Sci 2013;9(3): 16-21]. (ISSN: 1545-1003). http://www.jofamericanscience. org. 3