Association between Kidney Donor Risk Index, kidney graft function and histological changes in early post-transplant graft biopsy

Background Proper assessment of donor organ quality is crucial for optimal kidney allocation and best long-term outcomes. The aim of this study was to analyze the association between the Kidney Donor Risk Index (KDRI) and histological parameters in early post-transplant graft biopsy in a Polish cohort of kidney transplant recipients. Methods In 418 consecutive kidney transplant recipients, a histological evaluation of very early [at median 11 (9-13) post-transplant day] protocol core needle biopsy was performed and analyzed according to the Banff classification. Subjects were divided into quartiles of the KDRI value. Kidney graft function, patient and graft survival were also analyzed over a median follow-up period of 44 (26-56) months. Results There was a significant trend toward greater intensity of chronic histology changes along the KDRI quartiles (& chi;(2) = 20.8; P < .001), including interstitial fibrosis, tubular atrophy, mesangial matrix increase and arteriolar hyalinosis. Stepwise multivariate regression analysis revealed that only higher KDRI value independently increased the severity of chronic graft injury (r(partial) = 0.340, P < .001). KDRI values were valuable in the determination of both early and long-term graft function. Conclusion The KDRI values correlate with chronic histological changes found in early post-implantation kidney biopsies and can also be helpful in the prediction of graft outcome. Lay Summary We investigated an association between the Kidney Donor Risk Index (KDRI; based on donor demographics, medical history and factors related to donor death) and histological parameters in early post-transplant kidney graft biopsy. In 418 consecutive kidney transplant recipients, a histological evaluation of protocol core needle biopsy was performed and analyzed according to the Banff classification. More intense chronic histology changes including interstitial fibrosis, tubular atrophy, mesangial matrix increase and arteriolar hyalinosis were observed with increasing KDRI. Over 5 years of observation, post-transplant better kidney function (measured as higher estimated glomerular filtration rate) was observed with lower KDRI. There was no significant difference in the rate of early surgical complications, acute rejection episodes or the need for hospitalization due to a serious infection. Stepwise multivariate regression analysis revealed that only higher KDRI value independently increased the severity of chronic graft injury.