RIFLE classification and mortality in obstetric patients admitted to the intensive care unit with acute kidney injury: a 3-year prospective study.

OBJECTIVE: This study is to assess the correlation of risk, injury, failure, loss, and end-stage renal failure (RIFLE) classification with hospital mortality in intensive care unit (ICU) obstetric patients and to evaluate the relation of acute kidney injury (AKI) to other risk factors.

METHODS: The 4 stages of RIFLE (nonacute renal failure, risk, injury, and failure) were scored from 0 to 3 points, respectively. The prognostic performance of the RIFLE score was compared to the general ICU models.

RESULTS: AKI occurred in 30 (5.88%) of patients admitted to ICU. The main causes of AKI were hemolysis, elevated liver enzymes, and low platelet syndrome 13 (43%), pregnancy-related hypertension 9 (30%), puerperal sepsis 3 (10%), abruption placentae 2 (6.6%), disseminated intravascular coagulopathy 2 (6.6%), and anesthetic complications 1 (3.3%). According to the RIFLE criteria, patients were classified into Risk (3.3%), Injury (16.6%), Failure (33.3%), and Loss (46.6%). Maternal mortality from total ICU admission occurred in 51 (10%) cases, of these 16 (31.3%) cases were due to AKI. Independent risk factors associated with mortality were hyperbilirubinemia, low levels of HCO3, and RIFLE. Receiver-operator characteristic curves for ICU patients according to RIFLE score showed area under the curve = 0.824.

CONCLUSION: The RIFLE classification system could predict the risk of mortality from AKI in obstetric ICU patients and mortality was positively associated with high RIFLE classes.