The Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) equation best characterizes kidney function in patients being considered for lung transplantation

Abstract

Background: Methods for direct measurement of glomerular filtration rate (GFR) are expensive and inconsistently applied across transplant centers. The Modified Diet in Renal Disease (MDRD) equation is commonly used for GFR estimation, but is inaccurate for GFRs >60 ml/min per 1.73 m(2). The Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) and Wright equations have shown improved predictive capabilities in some patient populations. We compared these equations to determine which one correlates best with direct GFR measurement in lung transplant candidates.

Methods: We conducted a retrospective cohort analysis of 274 lung transplant recipients. Pre-operative GFR was measured directly using a radionuclide GFR assay. Results from the MDRD, CKDEPI, Wright, and Cockroft-Gault equations were compared with direct measurement. Findings were validated using logistic regression models and receiver operating characteristic (ROC) analyses in looking at GFR as a predictor of mortality and renal function outcomes post-transplant.

Results: Assessed against the radionuclide GFR measurement, CKDEPI provided the most consistent results, with low values for bias (0.78), relative standard error (0.03) and mean absolute percentage error (15.02). Greater deviation from radionuclide GFR was observed for all other equations. Pearson's correlation between radionuclide and calculated GFR was significant for all equations. Regression and ROC analyses revealed equivalent utility of the radionuclide assay and GFR equations for predicting post-transplant acute kidney injury and chronic kidney disease (p < 0.05).

Conclusions: In patients being evaluated for lung transplantation, CKDEPI correlates closely with direct radionuclide GFR measurement and equivalently predicts post-operative renal outcomes. Transplant centers could consider replacing or supplementing direct GFR measurement with less expensive, more convenient estimation by using the CKDEPI equation.

Keywords: CKDEPI; GFR equations; MDRD; lung transplantation; renal function.