Objective: To evaluate the association between donor gender and mortality after living donor liver transplantation (LDLT) with adjustment for size mismatch issues.
Methods: This retrospective cohort study analyzed 309 non-HCC male recipients who underwent LDLT between 2003 and 2016 in our center. Survival analysis was performed using the Cox model to compare death risk of recipients who received grafts from female donors (female donor group) and those who received graft from male donors (male donor group). Backward selection was performed for selecting variables during multivariable analysis. Size mismatch issues included the size/number/anastomosis type of the hepatic artery, hepatic vein, portal vein, and bile ducts (Table 1).
Results: The median follow-up time was 60 months. Death probability at 1/2/5 years after transplantation was 20.2/24.0/27.0% in female donor group and 8.1/10.1/13.5% in male donor group (Fig. 1). Death risk was significantly higher in male donor groupin univariable analysis (HR=2.28 [1.34–3.87], P=0.002) and in multivariable analysis (HR=1.88 [1.04-3.41], P=0.037). The following variables were included in the multivariable model: donor gender, operative year, ascites degree, encephalopathy degree, bile duct size, bile duct anastomosis type, and red blood cell transfusion. As shown in Fig. 1, the two groups showed most differences in death probabilities within 6 months after transplantation with 6-month mortality was 5.5% in female donor group versus 18.3% in male donor group (P<0.001).
Conclusion: Donor gender appears to be an important graft factor modulating death risk after LDLT irrespective of the size/number/anastomosis type of graft vessels and bile ducts. Possible mechanisms include the disparity in the changes in sex hormone receptors between male donor grafts and female donor grafts after transplantation.