BACKGROUND: Correction of hypovitaminosis D is simple, but it is unclear whether it is associated with an accelerated decline of renal allograft function in pediatric renal transplantation patients. This retrospective single center cohort study aimed at analyzing the effect of vitamin D and covariates on the slope of 1/creatinine after the first year.

MATERIAL AND METHODS: After ethics committee approval, 37 (14 male) pediatric renal transplant recipients on mycophenolate mofetil, who were followed between 2006 and 2014, were included in this study. We analyzed the slope of 1/creatinine, length of follow-up, average vitamin D levels, calcium, phosphate, alkaline phosphatase levels, intact parathyroid hormone (PTH) levels, and therapeutic drug monitoring parameters.

RESULTS: Median slope of 1/creatinine was –2.587e-006 L/µmol. We divided the 37 patients into two groups based on slope: 18 patients with a poorer slope and 19 patients with a good slope, with the median slope of 1/creatinine being significantly different between the two groups. Creatinine and cystatin C at one-year post-transplantation did not differ between the two groups. Average vitamin D levels were 71.4±31.01 pmol/L and identical in each group (averages 71.67 and 69.23 pmol/L, respectively). Only the mycophenolic acid coefficient of variation (MPA CV), which may promote formation of donor-specific antibodies, and PTH levels were significantly associated with 1/creatinine slope.

CONCLUSIONS: Our data suggest that the impact of mild and moderate decreased levels of vitamin D can have a mild impact on the progression of allograft dysfunction in transplant recipients. However, given the medication burden and adherence challenges in adolescents, correction of mildly decreased vitamin D levels may not be necessary.

Keywords: Calcifediol, Creatinine, cystatin C, Glomerular Filtration Rate, medication adherence, Parathyroid Hormone