Donor-to-recipient gender match in liver transplantation. A systematic review and meta-analysis

AIM To perform a systematic review and meta-analysis on donor-to-recipient gender mismatch as a risk factor for post-transplant graft loss. METHODS A systematic literature search was performed using PubMed, Cochrane Library database and EMBASE. The primary outcome was graft loss after liver transplantation. Odds ratios and 95% confidence intervals were calculated to compare the pooled data between groups with different donor-to-recipient gender matches. Three analyses were done considering (1) gender mismatches (F-M and M-F) vs matches (M-M and F-F); (2) Female-to-Male mismatch vs other matches; and (3) Male-to-Female mismatch vs other matches. RESULTS A total of 7 articles were analysed. Gender mismatch (M-F and F-M) was associated with a significant increase of graft loss respect to match (M-M and F-F) (OR: 1.30; 95%CI: 1.13-1.50; P < 0.001). When F-M mismatch was specifically investigated, it confirmed its detrimental role in terms of graft survival (OR: 1.83; 95%CI: 1.20-2.80; P = 0.005). M-F mismatch failed to present a significant role (OR: 1.09; 95%CI: 0.73-1.62; P = 0.68). CONCLUSION Gender mismatch is a risk factor for poor graft survival after liver transplantation. Female-to-male mismatch represents the worst combination. More studies are needed with the intent to better clarify the reasons for these results.