Predictive Value of CAR for Renal Survival and Mortality in ICU Patients with AKI Requiring Dialysis

Introduction: It has been reported that 20-60% of patients followed in the intensive care unit (ICU) develop acute kidney injury (AKI). Despite the critical care practices and different renal replacement therapies (RRT) applied in the ICU, reports indicate a high mortality rate of 50-60%. Thus, a need for a rapid, low-cost, readily accessible marker to be used in routine examinations is apparent, especially in terms of ICU mortality associated with AKI. Standard parameters used to measure inflammation and prognosis in critically ill patients are C-reactive protein (CRP) and albumin. Separately, high CRP levels and low albumin levels have been associated with poor prognosis and high mortality rates, making these two parameters well-documented for the use of predictive markers of mortality. The ratio between these two parameters has been a novel prognostic value for numerous diseases in recent years. Objective: The present study aimed to investigate the predictive value of C-reactive protein/albumin ratio (CAR) for renal survival and mortality in ICU patients with AKI requiring dialysis. Materials and methods: This retrospective study included data from 219 (119 males,100 females) ICU patients with AKI who required dialysis. The CAR was obtained by dividing the C-reactive protein(CRP) level with the albumin level. APACHE-II scores, frequently used in intensive care units for predicting mortality, were compared with CAR’s sensitivity and specificity. The primary endpoint of the study was a composite outcome of ICU mortality. The secondary endpoint of the study was renal survival.Results: During the ICU course, 165 (75.3%) patients died. In our study, the ROC analyses showed that the CAR could be used to predict renal survival and mortality in dialysis-requiring AKI in ICU patients. CAR’s sensitivity was higher than the APACHE -II score, and the specificity was similar to predicting ICU mor t al it y.Conclusion: To our knowledge, this is the first study to investigate CAR’s relationship with mortality and renal survival in ICU patients with acute kidney injury.