Association of Implantation Biopsy Findings in Living Donor Kidneys With Donor and Recipient Outcomes.

RATIONALE & OBJECTIVE: Some living donor kidneys are found to have biopsy evidence of chronic scarring and/or glomerular disease at implantation, but it is unclear if these biopsy findings help predict donor kidney recovery or allograft outcomes. Our objective was to identify the prevalence of chronic histological changes and glomerular disease in donor kidneys, and their association with donor and recipient outcomes.

STUDY DESIGN: Retrospective cohort study.

SETTING & PARTICIPANTS: Single center, living donor kidney transplants from January 2010 to July 2022.

EXPOSURES: Chronic histological changes, glomerular disease in donor kidney implantation biopsies.

OUTCOMES: (a) for donors, single kidney eGFR increase, percent total eGFR loss, ≥40% eGFR decline from pre-donation baseline, eGFR<60ml/min/1.73m2 at 6-months post-donation; (b) for recipients, death-censored allograft survival.

ANALYTICAL APPROACH: Biopsies were classified as having possible glomerular disease by pathologist diagnosis or chronic changes based on the percentage of glomerulosclerosis, interstitial fibrosis/tubular atrophy, and vascular disease. We used logistic regression to identify factors associated with the presence of chronic changes, linear regression to identify the association between chronic changes and single-kidney estimated glomerular filtration rate (eGFR) recovery, and time-to-event analyses to identify the relationship between abnormal biopsy findings and allograft outcomes.

RESULTS: Among 1104 living donor kidneys, 155 (14%) had advanced chronic changes on implantation biopsy, and 12 (1%) had findings suggestive of possible donor glomerular disease. Adjusted logistic regression showed that age (OR 2.44 per 10 years, 95%CI 1.98-3.01), Hispanic ethnicity (OR 1.87, 95%CI 1.15-3.05), and hypertension (OR 1.92, 95%CI 1.01-3.64), were associated with a higher odds of chronic changes on implantation biopsy. Adjusted linear regression showed no association of advanced chronic changes with single-kidney eGFR increase or relative risk of eGFR <60 ml/min/1.73m2 . There were no differences in time-to-death-censored allograft failure in unadjusted or adjusted Cox proportional hazards models when comparing kidneys with chronic changes to kidneys without histological abnormalities.

LIMITATIONS: Retrospective, absence of measured GFR.

CONCLUSION: Approximately 1 in 7 living donor kidneys had chronic changes on implantation biopsy, primarily in the form of moderate vascular disease, and 1% had possible donor glomerular disease. Abnormal implantation biopsy findings were not significantly associated with 6-month donor eGFR outcomes or allograft survival.