Acute renal failure needing dialysis in the intensive care unit and prognostic scores

Abstract

Background: Generic prognostic scores used in acute renal failure (ARE) give imprecise results; disease-specific indices applied to distinct populations or intensive care practices becomes inaccurate. the current study evaluates the adequacy of prognostic scores, in patients with severe ARE needing dialysis. Methods: Known generic (APACHE 11) and disease-specific (ATN-ISS) indices were applied to a cohort (n=280) with ARE needing dialysis, under intensive care. Possible risk factors as causal factors, organ dysfunctions and clinical variables were examined, and a local index assembled by multivariate logistic regression analysis. Area under the receiver operating characteristics (ROC) curves evaluated the indices discriminating capacity. Goodness-of-fit testing and linear regression analysis appraised calibration. Validation was accomplished by the bootstrapping technique. the end-point was hospital mortality. Results: Overall mortality Was 85%. Female gender <44 years (OR: 0.29; 95% CI: 0.10-0.84), liver/obstructive biliary disease (OR: 6.03; 95%CI: 1.65-22.08), being conscious (OR: 0.49; 95%CI: 0.21 - 1.14), use of vasoactive drug (OR: 3.13 95%CI: 1.25-7.83), respiratory dysfunction (OR: 5.20 95%CI: 1.25-7.83) or sepsis (OR: 2.62; 95%CI: 1.14-6.02) were associated with outcome. Areas under the ROC curve of 0.815, 0.652 and 0.814; Goodness-of-fit test P=0.593, P<0.001 and P=0.002; and linear regression R-2=0.973, R-2=0.526 and R-2=0.919 for the local index, APACHE 11 and ATN-ISS, respectively, indicate better performance by the local index. the local index median area under the ROC curve, by bootstrapping, was 0.820 (95% CI: 0.741-0.907). Conclusions: APACHE 11 score was inaccurate, and ATN-ISS poorly calibrated. When mortality or intensive care practices significantly deviate, local scores may better evaluate prognosis in severe ARF.