ARE PLASMA 1,25-DIHYDROXYVITAMIN D-3 CONCENTRATIONS APPROPRIATE AFTERSUCCESSFUL KIDNEY-TRANSPLANTATION

We studied 28 patients with parathyroid hormone (PTH) concentrations > 65 pg/ml immediately prior to kidney transplant and who had stable all ograft function with serum creatinine <2 mg/dl. After 12-18 months of transplantation, biochemical parameters (including 25-hydroxy- and 1,2 5-dihydroxy-vitamin D-3) were studied. Patients were divided into thre e groups according to their PTH concentrations. Patients with renal tr ansplant were compared with 50 healthy subjects and 20 patients with p rimary hyperparathyroidism. The mean 1,25-dihydroxy-vitamin D-3 concen tration of the transplant patients did not differ from the controls, b ut was lower than in patients with primary hyperparathyroidism. Using univariate linear regression analysis, 1,25-dihydroxy vitamin D-3 corr elated positively with PTH (P=0.008) and serum calcium (P=0.0015), and inversely with creatinine clearance (P=0.01). However, it did not cor relate significantly with serum phosphorus. Our data suggest that rena l transplant recipients may have an inappropriate production of 1,25-d ihydroxy vitamin D-3; suboptimal allograft function may be a major lim iting factor.