Estimation of glomerular filtration rate based on dry lean body mass in kidney transplant recipients

• Published in: Clinical nephrology Vol. 92; no. 6; p. 287
• Main Authors: Borštnar, Špela, Lindič, Jelka, Ležaič, Luka, Sočan, Aljaž, Godnov, Uroš, Kovač, Damjan
• Format: Journal Article
• Language: English
• Published: Germany 01-12-2019
• Subjects: Adult; Aged; Body Composition; Creatinine - blood; Cystatin C - blood; Female; Glomerular Filtration Rate; Humans; Kidney Transplantation; Male; Middle Aged; Prospective Studies; Renal Insufficiency, Chronic - physiopathology
• ISSN: 0301-0430
• DOI: 10.5414/CN109882

The use of glomerular filtration rate (GFR) estimating equations is not always reliable, especially in specific populations, such as patients with transplanted kidney. The purpose of this study was to improve the performance of GFR equations by taking into account dry lean body mass.
A prospective clinical study included 100 patients with kidney graft. Estimated GFR (eGFR) with Chronic Kidney Disease Epidemiology Collaboration equations with serum creatinine concentration (CKD-EPI Cr), serum cystatin C concentration (CKD-EPI CysC), or both (CKD-EPI Cr-CysC) were compared with measured GFR with
Cr-EDTA clearance (mGFR
Cr-EDTA). Dry lean body mass (body mass without fat mass and water) was measured with bioimpedance analysis.
All of the eGFRs overestimated mGFR
Cr-EDTA by a significant degree (shown as bias ± SD in mL/min/1.73m
with 30% accuracy in parentheses): CKD-EPI Cr 15.1 ± 15.3 (50%), CKD-EPI CysC 8.0 ± 16.6 (56%), CKD-EPI Cr-CysC 10.3 ± 13.4 (55%). Dry lean body mass significantly correlated with mGFR
Cr-EDTA (R = 0.241; p = 0.016) and all biases except the bias of CKD-EPI CysC. Considering the dry lean body mass and preexisting equations with creatinine, we developed two new equations with better performance and statistically insignificant bias: Corrected CKD-EPI Cr -1.43 ± 13.6 (67%) and Corrected CKD-EPI Cr-CysC -1.64 ± 13.4 (77%).
Dry lean body mass improves the performance of GFR equations in our kidney transplant cohort.