A Single-Center Retrospective Study to Identify Causes of Sex Differences in the Living Kidney Donor Evaluation Process.

Abstract

Background: Multiple studies have shown that females are living donors for kidney transplantation at higher rates than males. However, the underlying reasons for this observation are not well-understood. We examined the living donor evaluation process to determine the point at which sex imbalance arises. Based on a previous study, we hypothesized that both sexes are equally likely to become approved as living donors, but females are more likely to follow through with donation.

Methods: Single institution retrospective chart review of self-referrals for living donor evaluation between 1/2009 - 12/2022. Self-referrals identified using the Organ Transplant Tracking Record database and cross referenced with billing data. Exclusion at each stage of evaluation was recorded and compared between sexes using log binomial regression; unadjusted and adjusted (for donor age, race, ethnicity, relationship to recipient, and recipient sex) risk ratios (RRs) with 95% confidence interval (CI) were determined.

Results: 1,861 self-referrals were reviewed, including 1,214 (65.2%) females and 647 (34.8%) males, resulting in 146 approvals and 125 donations (76/125, 60.8% females, 49/125 39.2% males). Adjusted RRs indicated no significant differences between sexes in completing medical and/or psychosocial workup, having medical and/or psychosocial contraindications, being approved for donation, and proceeding with donation. The top medical contraindications for both sexes were obesity, hypertension, and nephrolithiasis.

Conclusion: Female overrepresentation among living donors is likely due to the 1.9 times higher rate of self-referral for evaluation. After this point, both sexes were equally likely to complete workup, be approved, and follow through with donation. Increased efforts to engage males at the initial self-referral stage has the potential to expand access to living donor kidney transplantation.