Treatment of donors' asymptomatic small kidney stones and post-transplant outcomes: a meta-analysis

Kidney donors with asymptomatic small kidney stones were increasingly accepted in kidney transplantation (KT) due to organ shortage and advances in endoscopic urology. However, recipients' clinical outcomes using these donors remained unclear. We conducted a meta-analysis to summarize transplant outcomes using these donors with asymptomatic small kidney stones. Finally, 15 retrospective studies were included. The prevalence of asymptomatic small kidney stones was 5.3% (95%CI 3.5-7.8%). After transplantation, low incidence of urinary fistula (0%, 95%CI 0-1.0%), obstruction (0%, 95%CI 0-1.1%), relapse of kidney graft stone (0.3%, 95%CI 0-2.5%), and delayed graft function (0.6%, 95%CI 0-3.5%) was reported. Pooled serum creatinine was 1.3 (95%CI 1.2-1.5) mg/dl and 1.4 (95%CI 1.2-1.6) mg/dl at post-transplant 1 month and 1 year, respectively. Notably, we observed numerically higher relapse rate after conservative management (1.8% [0-9.2%] vs 0% [0-1.8%]) but numerically higher DGF rate after surgical removal of asymptomatic stones (1.8% [0-7.0%] vs 0% [0-1.9%]). Overall, short-term transplant outcomes using kidneys with asymptomatic small stones were acceptable. However, long-term transplant outcomes remained unexplored. Well-designed prospective studies are also needed to compare the efficacy of conservative management with surgical removal of "donors' gifted" asymptomatic kidney stones.