The effect of donor-recipient sex matches on lung transplant survival: An analysis of the United Network for Organ Sharing database

<bold>Objective: </bold>To investigate the impact of donor-recipient (DR) sex matches on survival after lung transplantation while controlling for size difference in the United Network of Organ Sharing (UNOS) database. <bold>Methods: </bold>We performed a retrospective study of 27,423 lung transplant recipients who were reported in the UNOS database (January 2005-March 2020). Patients were divided into groups based on their respective DR sex match: male to male (MM), male to female (MF), female to female, (FF), and female to male (FM). Kaplan-Meier curve and Cox regression with log-rank tests were used to assess 1-, 3-, 5-, and 10-year survival. We also modeled survival for each group after controlling for size-related variables via the Cox regression. <bold>Results: </bold>Kaplan-Meier curves showed overall significance at 1-, 3-, 5-, and 10-year end points (P < .0001). Estimated median survival time based on Kaplan-Meier analysis were 6.41 +/- 0.15, 6.13 +/- 0.18, 5.86 +/- 0.10, and 5.37 +/- 0.17 years for FF, MF, MM, and FM, respectively (P < .0001). After we controlled for size differences, FF had statistically significantly longer 5- and 10-year survival than all other cohorts. MF also had statistically significantly longer 5- and 10-year survival than FM. <bold>Conclusions: </bold>When variables associated with size were controlled for, FF had improved survival than other DR groups. A female recipient may experience longer survival with a female donor's lungs versus a male donor's lungs of similar size.