PURPOSE:RIFLE Criteria (Risk of kidney dysfunction, Injury to kidney, Failure of kidney function, Loss of kidney function, End-Stage kidney disease) for classification of Acute Kidney Injury (AKI) was introduced recently and used for risk stratification in ICU patients. The studies done were on Caucasian predominant patient population. Therefore, we intended to apply “Risk,” “Injury,” and “Failure” of the RIFLE Criteria for severity classification of AKI in African American predominant critically ill patients, and to investigate the association between the severity class and hospital mortality and morbidity.
METHODS:Retrospective review of 236 patients admitted to Med-Surg ICU during one year period. Patients were classified generally into Control group and AKI group; the latter is further classified into Risk, Injury, and Failure subgroups by using Creatinine criteria, Urine Output criteria, and maximum RIFLE class using both criteria. Demographics, morbidity data, biochemical data, and patient outcome data collected.
RESULTS:93.64% of study population is African American. Gender wise, female predominate (65.9%) in the Control group and male (54.3%) in the AKI group. AKI per maximum RIFLE class occurred in 151 (49.67%) patients; 55 (36.42%) patients were at risk, 58 (38.41%) had injury, and 38 (25.17%) had failure. When creatinine level alone is used, AKI occurred in 125 patients; 57 (37.8%) are at risk, 33 (21.9%) had injury, and 34 (22.5%) are in failure. Using urine output criteria, it is found only in 100 patients; Risk 43 (28.5%), Injury 49 (32.5%), Failure 8 (5.3%). Patients with AKI by maximum RIFLE class have an overall hospital mortality rate of 21.19% compared to 9.41% among the control (p=0.025). AKI by creatinine criteria and urine output criteria showed mortality rates of 23.2% and 24% respectively; where as their control have 9.9% and 11.8% respectively (p=0.007 and p=0.013 respectively). The mortality rates of Risk, Injury and Failure: 18.2%, 20.7%, and 26.2% respectively in maximum RIFLE class (p=0.092); 24.1%, 18.2%, and 26.5% respectively by creatinine criteria (p=0.03); and 11.6%, 28.6% and 62.5% respectively by urine output criteria (p=0.0002). Patients with Higher RIFLE grades are also found to have longer hospital length of stay (p=0.1928), longer ICU length of stay (p=0.0087), longer ventilator days (p<0.0001), and greater number of organ dysfunction (p=0.0151).
CONCLUSION:Our data showed rising mortality trend with increasing AKI severity grade in African American predominant intensive care patient population. In addition, it also showed a strong association between RIFLE severity grade and longer ICU stay, longer ventilator days, and greater number of organ dysfunction.
CLINICAL IMPLICATIONS:Our study supports existing data on outcome of critically ill patients with AKI using RIFLE,and thus,applicable to African American population for risk stratification in ICU.
DISCLOSURE:Yin Naing, No Financial Disclosure Information; No Product/Research Disclosure Information