The incidence and risk factors of acute renal failure in critically ill patients according to RIFLE And AKIN classifications

In this trial, our aim was to evaluate the incidence and risk factors for acute renal failure (ARF) classified according to AKIN and RIFLE systems and to compare these classifications with each other. Totally 396 patients were recruited from Intensive Care Unit (ICU) of the Gazi University Faculty of Medicine between January 2008 and July 2010. Onadmission, for all patients laboratory values, glaskow coma scores, APACHE II and SOFA scores were evaluated. Basal creatinine levels of all patients were calculated by assuming GFR as 75 ml/min according to MDRD formula for RIFLE classification. AKIN classification was performed according to the highest increase in creatinine levels in 48 hour periods during hospitalization. Most serious AKIN and RIFLE scores were recorded. According to RIFLE classification, 218 of 396 patients were classified as ARF (44 ones in risk group, 68 ones in injury, 106 ones in failure). Patients in injury and failure groups had higher mortality rates. According to AKIN classification system, 182 of 396 patients had ARF ( 79 ones in stage 1, 13 ones in stage 2, 90 ones in stage 3). Patients in stage 2 and 3 had higher mortality rates. Advanced age, higher APACHE II and SOFA scores, lower glaskow coma scores, long lenght of stay in ICU, presence of hypertension, low bicarbonate and pH levels were detected as independent risk factors for development of ARF according to RIFLE system. Younger age, higher APACHE II and SOFA scores, long length of stay in ICU, presence of hypertension, low ph levels were detected as independent risk factors for development of ARF according to AKIN system. ICU survival was significantly related with AKIN classification but not with RIFLE classification. Hospital survival was related with both classification systems. Observation of majority of the patients with ARF into failure group and stage 3 according to RIFLE and AKIN systems respectively could be attributable to progression of ARF to severe classes in ICU stay. Additionally, the mortality rates were higher in patients with ARF. The differences in numbers of patients classified as ARF, risk factors for development of ARF and survival rates in both groups could be caused of distinct classification criteria and assumption of GFR as 75 ml/min for RIFLE system. We could not evaluate the urine output criteria because of insufficient data for urine collection for both systems. So, this could lead to discrepancy in stages and incidence of ARF. Although, ARF incidence was higher according to RIFLE system, AKIN seems more sensitive in case of ICU survival.