Renal function evaluated by measured GFR during follow-up in pediatric liver transplant recipients

Calcineurin inhibitors form the mainstay of immunosuppression in pediatric liver transplantation, but may cause significant nephrotoxicity. We evaluated renal function in liver transplant recipients treated with a tacrolimus-based immunosuppressive regimen. GFR was measured using 99 mTc-DTPA in patients pretransplant and annually thereafter. GFR calculated by Schwartz formula was compared with the measured values. Sixty patients who underwent 69 transplants were followed for at least one yr post-transplant (median three yr). In children over two yr of age at transplant GFR fell significantly from pretransplant (140 mL/min/1.73 m(2)) to one yr post-transplant (112 mL/min/1.73 m(2)) (p = 0.01) but thereafter there was no significant decline. In younger children the picture was confounded by maturation of renal function, but again there was no significant fall to five yr post-transplant. Although 13 (22%) patients developed renal dysfunction post-transplant, none required renal replacement therapy. cGFR correlated poorly with measured values (r = 0.21). Use of a tacrolimus-based immunosuppressive regimen is associated with an initial decline in GFR, though this picture is confounded in younger children by normal maturation of renal function. There is no further significant fall in GFR in the medium-term. The Schwartz formula is inaccurate in determining GFR in this patient group.