Clinical factors associated with initiation of renal replacement therapy in critically ill patients with acute kidney injury—A prospective multicenter observational study

Abstract Purpose Our objective was to describe the current practice for initiation of RRT in this population. There is uncertainty regarding the optimal time to initiate renal replacement therapy (RRT) in critically ill patients with acute kidney injury (AKI). Methods Prospective study of patients receiving RRT in 6 intensive care units (ICUs) at 3 hospitals from July 2007 to August 2008. We characterized factors associated with start of RRT and evaluated their relationship with mortality. Results We included 234 patients. RRT was initiated 1 day (0-4) after ICU admission (median [interquartile range]). Median creatinine was 331 μ mol/L (225-446 μ mol/L), urea 22.9 mmol/L (13.9-32.9 mmol/L), and RIFLE-Failure in 76.9%. Of traditional indications, Pa o 2 /Fi o 2 μ mol/L (odds ratio [OR] 2.8; 95% confidence interval [CI] 1.5-5.4), change in urea from admission >8.9 mmol/L (OR 1.8; 95% CI, 1.0-3.4), urine output 3.0 L/24 hours (OR 2.3; 95% CI, 1.2-4.5), percentage of fluid overload >5% (OR 2.3; 95% CI, 1.2-4.7), 3 or more failing organs (OR 4.5; 95% CI, 1.2-4.2), Sequential Organ Failure Assessment score >14 (OR 2.3; 95% CI, 1.3-4.3), and start 4 days or more after admission (OR 4.3; 95% CI, 1.9-9.5). Mortality was higher as factors accumulated. Conclusion In ICU patients requiring RRT, there was marked variation in factors that influence start of RRT. RRT initiation with fewer clinical triggers was associated with lower mortality. Timing of RRT may modify survival but requires appraisal in a randomized trial.