A Study of the Applicability of GFR Evaluation Equations for an Elderly Chinese Population

This study screened current GFR evaluation equations that showed high accuracy for elderly populations and evaluated the applicability of these equations for an elderly Chinese population.

A standard dual plasma sampling method (DPSM) of estimating 99mTc-diethylene triamine penta-acetic acid clearance was used to determine measured GFR (mGFR).

Comprehensive information was received for a total of 151 elderly individuals, with a mean mGFR of 65.39 ± 24.19 ml/min/1.73 m2. For the overall samples, the accuracy (P30), bias, absolute bias and interquartile ranges (IQRs) of the CKD2 (cystatin C(CysC)-serum creatinine(SCr)), CKD-EPI(CysC-SCr), Cockcroft-Gault(CG), CKD2(CysC), CKD-EPI(CysC), and Hoek equations were superior to c-aGFR3, c-aGFR4 and Grubb equation, Bland-Altman analysis also demonstrated a consistent result. Among elderly subjects with mGFR≥60 ml/min/1.73 m2, the CKD2 (CysC-SCr) and CKD-EPI (CysC-SCr) equations showed significantly higher correlations and accuracy than the other examined equations. Among elderly subjects with mGFR<60 ml/min/1.73 m2, only the CG equation showed an accuracy (P30) of greater than 70% and demonstrated higher precision than the other examined equations.

For the elderly population, the CG, CKD2, CKD-EPI, and Hoek equations exhibited good accuracy. The CKD2(CysC-SCr) equation and CKD-EPI(CysC-SCr) equation demonstrated relatively high accuracy for evaluating elderly subjects with mGFR≥60 ml/min/1.73 m2, whereas the CG equation was more suitable for evaluating elderly subjects with mGFR<60 ml/min/1.73 m2.