Abstract 14631: Comparison of Risk-Prediction for Early Mortality after Heart Transplantation Using the MDRD and the CKD-EPI Equations for Estimated GFR
Renal function at transplant is an independent risk-factor for early mortality after heart transplant (HT). A new equation for estimating glomerular filtration rate (GFR) - the Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI] equation - is better at predicting outcomes in general population than the Modification of Diet in Renal Disease (MDRD) equation; however their performance in predicting post-transplant mortality in HT recipients has not been compared. We sought to compare risk-prediction of early post-HT mortality using estimated GFR from the MDRD and the CKD-EPI equations.
Methods: We identified all subjects ≥18 years of age who underwent primary HT in the US between 01/2007 and 10/2010 (N=6564) and developed risk-prediction models for post-transplant in-hospital mortality using estimated GFR from the MDRD and the CKD-EPI equations. GFR categories assessed were ≥90, 60-89, 30-59 and <30 (ml/min/1.73 m2). Models were compared using the traditional measures of model-fit and the reclassification statistics.
Results: Overall post-transplant hospital mortality was 4.6 %. Using the MDRD equation and GFR ≥90 as the reference, GFR categories of 60-89 (Odds ratio [OR] 1.5, 95% CI 1.0, 2.3), 30-59 (OR 2.2, CI 1.4, 3.3) and <30 (OR 3.3, CI 1.8, 6.1) were all associated with in-hospital mortality adjusted for other predictors (age, diagnosis, mechanical and ventilator support, serum bilirubin, donor age and ischemic time, all P<0.001). GFR estimated using the CKD-EPI equation reclassified 15% of HT recipients with GFR 30-59 and 18% of GFR 60-89 into the next higher GFR category. Model using the CKD-EPI equation and the model using the MDRD equation showed similar discrimination (C-statistic) and calibration. However, use of the CKD-EPI equation resulted in a negative net reclassification improvement for the entire study cohort (-0.0038) and for patients whose GFR was reclassified from the 30-59 category to the 60-89 category (-0.025).
Conclusions: The CKD-EPI equation to estimate GFR is not superior to the MDRD equation in predicting early post-transplant mortality in HT recipients adjusted for other risk factors.
- © 2012 by American Heart Association, Inc.