Sex-Based Differences in Early and Late Kidney Outcomes After Heart Transplantation.

Background: The development of kidney disease after heart transplantation (HT) has been well described and is associated with increased post-HT mortality. Limited data have evaluated sex-based differences in kidney outcomes post-HT.

Methods: Adults (≥ 18 years old) in the United Network for Organ Sharing registry who underwent HT between 2010 and 2022 were included. Multiorgan transplants were excluded as were patients who required dialysis pre-HT. Baseline characteristics were compared by sex. Outcomes included early kidney failure (need for post-operative dialysis) and late kidney failure (chronic dialysis or kidney transplantation). Multivariable logistic regression was used to determine whether sex predicted development of early kidney failure, and multivariable Cox regression was used to determine whether sex predicted late kidney failure. Outcomes were also compared before and after the 2018 heart-allocation system change.

Results: We included 30,414 HT recipients (n = 8223, 27.0% female); 3535 patients (n = 891, 25% female) developed early kidney failure post-HT. After adjusting for multiple clinical factors, sex was not found to be a significant predictor of early kidney failure post-HT (OR 0.93, 95% CI 0.83-1.04; P = 0.2). Following implementation of the 2018 allocation system, rates of early renal failure increased significantly in both men (10% to 14%; P < 0.001) and women (9% to 13%; P < 0.001), but the effect was similar by sex (P-interaction: > 0.9). Over a median follow-up of 5 years (IQR 2.4-8.0), there were no differences in time to late kidney failure by sex (log rank P = 0.4). After adjustment for various clinical and demographic factors, there was no difference in risk of late kidney failure by sex (aHR 1.11, 95% CI 0.96-1.27; P = 0.2).

Conclusions: Although sex did not predict the development of early or late kidney failure after HT, future studies are needed to determine sex-specific risk factors for kidney failure and potential preventive strategies.