RIFLE classification in patients with acute kidney injury in need of renal replacement therapy.

Abstract

To evaluate the association of RIFLE classification with the outcomes of critically ill patients with acute kidney injury (AKI) who require renal replacement therapy (RRT). Prospective cohort study in the medical-surgical ICUs at three tertiary hospitals. 214 patients over 1 year (mean age 71.4+/-15.8 years). Continuous RRT was used in 179 (84%); patients were classified as risk (25%), injury (27%), or failure (48%). Overall mortality was 76%. There were no significant differences according to RIFLE classification (risk 72%, injury 79%, failure 76%). Variables selected in multivariate analysis were: older age (OR 1.03, 95% CI 1.01-1.06), presence of comorbidity (3.15, 1.10-9.02), poor chronic health status (6.51, 1.95-21.71), number of associated organ dysfunctions (patients with one or two organ dysfunctions 5.93, 2.03-17.33; patients with three or more organ dysfunctions 26.76, 6.28-114.11), and start of RRT after the first day of ICU (2.46, 1.09-5.53). RIFLE classification was forced into the model and was not selected. However, a subgroup analysis of 150 patients who received mechanical ventilation and vasopressors found failure to be associated with increased mortality (3.58, 1.08-11.80). Older age, number of organ dysfunctions, presence of comorbidities, and reduced functional capacity were the main prognostic factors. Patients who required RRT after the first day of ICU had a worse outcome. The RIFLE classification did not discriminate the prognosis in patients with AKI in need for RRT.