Sex disparities in the current era of pediatric heart transplantation in the United States

Background: While sex-related differences in transplant outcomes have been well characterized amongst adults, there are no sex-specific pediatric heart transplant studies over the last decade and none evaluating waitlist outcomes. In a contemporary cohort of children undergoing heart transplantation in the United States, this analysis was performed to determine if there were sex disparities in waitlist and/or post-transplant outcomes.

Methods: Retrospective review of Scientific Registry of Transplant Recipients database from December 16, 2011 to February 28, 2019 to compare male and female children after listing and after transplant. Demographic, clinical characteristics and outcomes were compared unadjusted and after 1:1 propensity matching for selected covariates.

Results: Of 4089 patients, 2299 (56%) were males. At listing, males were more likely to be older, have congenital heart disease (58% vs 48%), renal dysfunction (49% vs 44%) and implantable cardioverter defibrillator (9% vs 7%). At transplant, males were more likely to have renal (42 % vs 35%) and liver dysfunction (13% vs 10%), PRA >10% (29% vs 22%) and ischemic time >3.5 hours (p < 0.05 for all). There were no significant sex differences found in unadjusted rates of transplant or mortality. After propensity matching, females had increased waitlist mortality (HR 1.3, 95%CI 1.04-1.5; p =0.019) compared to males. There were no significant differences in post-transplant morbidity or mortality (HR 1.2, 95% CI 0.93-1.5; p = 0.18) between groups.

Conclusion: In a contemporary pediatric cohort, females have inferior heart transplant waitlist survival compared to propensity-matched males despite lower acuity of illness at listing and similar rates of transplantation. There were no sex-disparities noted in post-transplant outcomes.