New equation for estimating glomerular filtration rate in Vietnamese kidney transplant recipients

Accurate assessment of kidney function is essential for post-kidney transplant management. This study aims to develop a new equation tailored to Vietnamese kidney transplant recipients and validate its performance against established equations.

A total of 299 kidney transplant recipients underwent glomerular filtration rate (GFR) measurement using technetium-99m-diethylenetriaminepentaacetate renal dynamic scintigraphy, along with demographic, clinical, and laboratory assessments. Participants were divided into a development cohort (n = 150) to generate a new GFR-estimating equation and a validation cohort (n = 149) for internal validation against six equations.

The new equation, $GFR=100.430\times 1.{080}^{\mathrm{sex}}\times ag{e}^{-0.097}\times Sc{r}^{-0.524}\times Scy{s}^{-0.435}$ (sex: 0 = female; 1 = male), showed the smallest median bias (-0.11 [-1.40; 1.11]), highest P₃₀ accuracy (94.0% [88.6; 96.6]), highest precision (interquartile range = 9.82 [7.63; 12.37]), and strongest correlation with measured GFR (r = 0.824 [0.752; 0.880]) among tested equations in the validation cohort. Among creatinine-based equations, the Modification of Diet in Renal Disease equation was the most accurate.

The new equation outperformed established equations and is recommended for Vietnamese kidney transplant recipients. The Modification of Diet in Renal Disease equation may serve as an alternative in centers lacking access to serum cystatin C. Further studies with larger cohorts, external validation, and comparisons with gold-standard GFR measurement methods are needed to confirm these results.