Timing of renal replacement therapy and clinical outcomes in critically ill patients with severe acute kidney injury

The aim of this study is to evaluate the relationship between timing of renal replacement therapy (RRT) in severe acute kidney injury and clinical outcomes. This was a prospective multicenter observational study conducted at 54 intensive care units (ICUs) in 23 countries enrolling 1238 patients. Timing of RRT was stratified into "early" and "late" by median urea and creatinine at the time RRT was started. Timing was also categorized temporally from ICU admission into early ( <2 days), delayed (2-5 days), and late (>5 days). Renal replacement therapy timing by serum urea showed no significant difference in crude (63.4% for urea <or=24.2 mmol/L vs 61.4% for urea >24.2 mmol/L; odds ratio [OR], 0.92; 95% confidence interval [CI], 0.73-1.15; P = .48) or covariate-adjusted mortality (OR, 1.25; 95% CI, 0.91-1.70; P = .16). When stratified by creatinine, late RRT was associated with lower crude (53.4% for creatinine >309 micromol/L vs 71.4% for creatinine <or=309 micromol/L; OR, 0.46; 95% CI, 0.36-0.58; P < .0001) and covariate-adjusted mortality (OR, 0.51; 95% CI, 0.37-0.69; P < .001). However, for timing relative to ICU admission, late RRT was associated with greater crude (72.8% vs 62.3% vs 59%, P < .001) and covariate-adjusted mortality (OR, 1.95; 95% CI, 1.30-2.92; P = .001). Overall, late RRT was associated with a longer duration of RRT and stay in hospital and greater dialysis dependence. Timing of RRT, a potentially modifiable factor, might exert an important influence on patient survival. However, this largely depended on its definition. Late RRT (days from admission) was associated with a longer duration of RRT, longer hospital stay, and higher dialysis dependence