Predictive Model for the Optimal Glomerular Filtration Rate in Living Kidney Transplant Recipients

Abstract

Background: Recipient glomerular filtration rate (r-GFR) after living kidney transplantation (KT) is influenced by many factors. Optimal r-GFR is varied among different recipient-donor pairs. The defining of “appropriate level” of r-GFR post KT is challenging and helpful in clinical practice. The aim of this study is to establish a predictive model to estimate the optimal r-GFR post KT. Methods: We examined the clinical data of all living donors and recipients performed at our institution between January 2000 and December 2011. Recipients with delayed graft function, rejection and other complications resulting in impaired graft function were excluded. Estimated GFR was calculated using Cockcroft-Gault (CG) and 6 variable MDRD formulae. Donor kidney volume was obtained by work station GE (AW 4.20) program from routine computed tomographic angiography of donor kidneys. Multivariate analysis was carried out with automated backward selection to establish predictive model. Results: Of 211 uncomplicated KT recipients, the mean r-GFR calculated by CG formula (CG r-GFR) at one week post KT was 62.20 ± 17.07 ml/min and the mean serum creatinine was 1.28 ± 0.37 mg/dl. In univariated analysis, factors significantly correlated with one week CG r-GFR are donor kidney volume (R = 0.467, p< 0.0001), donor GFR (R=0.299, p< 0.001), and recipient body surface area (R=0.303, p< 0.0001). In multivariate analysis, significant correlation was identified only for donor age and kidney volume and both were incorporated in predictive model; Predicted CG r-GFR = 28.325 + (Donor Kidney Volume× 0.282) - (0.297 ×Donor Age). The correlation coefficient (R) of determination of this model is 0.5. Conclusion: The use of predictive model which included “donor age” and “donor kidney volume” can estimate the optimal r-GFR post KT. This could be helpful to identify early graft dysfunction and help in decision making if further invasive investigation such as allograft biopsy is necessary.