How good is a living donor? Systematic review and meta-analysis of the effect of donor demographics on post kidney transplant outcomes

Background and Aims Living donor kidneys are considered the best quality organs. In the attempt to expand the donor pool, the donor’s age, sex and body mass index (BMI) might be considered as potential determinants of the kidney transplant outcomes, and thus guide recipient selection. We aimed to investigate the effects of donor demographics on kidney function, graft and recipient survival, delayed graft function (DGF) and acute rejection (AR). Methods Systematic review and meta-analysis. EMBASE, MEDLINE, Web of Science, BIOSIS, CABI, SciELO and Cochrane were searched using algorithms. NHBLI tools were used for risk of bias assessment. Mean difference (MD), standardized mean difference (SMD), and risk ratio (RR) were calculated in Revman 5.4 Results Altogether, 5129 studies were identified by the search algorithm; 47 studies met the inclusion criteria and were analyzed. No significant difference in recipient 1-year survival was found between recipients of donors aged < 50 vs donors aged > 50 (RR = 0.65 95% CI: 0.1–4.1), and recipients of donors aged < 60 vs donors aged > 60 (RR = 0.81 95% CI: 0.3–2.3). Graft survival was significantly higher in recipients of grafts from donors aged < 60. Risk of AR (RR = 0.62 95% CI: 0.5–0.8) and DGF (RR = 0.28 95% CI: 0.1–0.9) were significantly lower in recipients of grafts from donors aged < 60. One-year serum creatinine was significantly lower in recipients from donors aged < 60 years compared to donors aged > 60 years (MD = 0.3 mg/dl 95% CI: 0.1–0.9), although there was high heterogeneity. Recipients of grafts from male donors had lower 1-year serum creatinine (MD = 0.12 mg/dl 95% CI: 0.2–0.1) and higher eGFR compared to recipients of female donors (p < 0.00001). Donor obesity increased the incidence of delayed graft function but not acute rejection (RR = 0.66 95% CI: 0.32–1.34). Conclusions Older donor age was associated with worse post-transplant outcomes and recipients of male donors had better 1-year eGFR. Donor obesity affects the incidence of delayed graft function, but not the incidence of acute rejection in recipients.