Differences in mortality by donor sex and age in heart transplantation: An individual patient data meta-analysis

Prior studies suggested a recipient sex-dependent association between donor sex and heart transplant survival. We hypothesized that donor age also modifies the association between donor sex and recipient mortality.

Deceased donor heart transplant recipients (1988-2019, n = 109,432) recorded in the Scientific Registry of Transplant Recipients (SRTR) and the Collaborative Transplant Study (CTS) were analyzed. We used multivariable Cox regression models to estimate the association between donor sex and mortality, accounting for the modifying effects of recipient sex and donor age. Results from cohort-specific models were combined using individual patient data meta-analysis.

Among female recipients, mortality was lower with female than male donors across all donor age groups, though differences were not statistically significant. Among male recipients, female donors aged 13-44 years were associated with higher mortality compared with male donors, although the difference was not statistically significant. In sensitivity analyses, aHR comparing mortality associated with female vs male donors were lower after adjusting for donor-recipient heart size mismatch. Female recipients of female donors aged 18-44 years had significantly lower mortality than recipients of same-aged male donors. Among male recipients of donors aged ≥45 years, mortality was significantly lower with a female than a male donor.

Donor age modifies the association between donor sex and survival after heart transplantation. When appropriately size-matched, female donors are associated with similar or lower mortality compared with male donors in both female and male recipients, suggesting a potential survival advantage with female donor hearts.