Nephrology consultation in acute renal failure*1: Does timing matter?

Purpose Patients who develop acute renal failure in the intensive care unit (ICU) have extremely high rates of mortality and morbidity. The goals of this study were to identify correlates of the timing of nephrology consultation in acute renal failure, and to explore the relation between timing of consultation and outcomes. Methods We explored associations among timing of nephrology consultation and in-hospital mortality, lengths of hospital and ICU stay, and recovery of renal function in 215 ICU patients with acute renal failure at four U.S. teaching hospitals. We used multivariable logistic regression and propensity scores to adjust for confounding and selection effects. Results Nephrology consultation was delayed (≥48 hours) in 61 patients (28%) (median time to consultation, 4 days). Lower serum creatinine levels (P<0.0001) and higher urine output (P = 0.002) were associated with delayed consultation. Delayed consultation was associated with increased mortality among dialyzed (31/42 [74%] vs. 50/103 [49%], P = 0.006) and nondialyzed patients (10/19 [53%] vs. 11/51 [22%], P = 0.01), and increases in lengths of hospital (median, 19 days vs. 16 days, P = 0.01) and ICU stay (17 days vs. 6 days, P<0.0001). The association between delayed consultation and mortality was attenuated by covariate adjustment, and was no longer statistically significant after adjustment for propensity score (odds RATIO = 2.0; 95% confidence interval: 0.8 to 5.1). Conclusion In acute renal failure, delayed nephrology consultation was associated with increased mortality and morbidity, whether or not dialysis was ultimately required. Using observational data, we cannot determine whether these findings reflect residual confounding, selection bias, adverse effects of delayed recognition of acute renal failure, or the benefits of nephrology consultation.