Vitamin D deficiency is an independent risk factor for PTDM after kidney transplantation

An association between 25 hydroxyvitamin D [25(OH)D] deficiency and type 2 diabetes was observed in the general population. Such association was not investigated in kidney transplant recipients. We prospectively evaluated 444 patients following primary kidney transplantation between 2000 and 2010. The 25(OH)D level at transplantation was classified into three grades: deficiency (< 10 ng/ml), insufficiency (≥ 10 and < 30 ng/ml), and normal range (≥ 30 ng/ml). Time to Post-Transplant Diabetes Mellitus (PTDM) was defined according to the day of first prescription of hypoglycemic treatment. The 25(OH)D level at transplantation was deficient in 88 patients, insufficient in 264 patients, and normal in 92 patients. At 1 year post-transplantation, cumulative incidence of PTDM was 13.2%. Cox multivariate analysis indicated that 25(OH)D deficiency (≤ 10 ng/ml) at the time of transplantation was an independent risk factor for PTDM within the first year post-transplantation (HR = 2.41, 95% CI 1.01-5.75, P = 0.048), whereas insufficiency tended to increase this risk, although not significantly. 25(OH)D deficiency is a new independent risk factor for PTDM within the first year after kidney transplantation. Our study suggests that 25(OH)D may be a marker of general health in kidney transplant recipients and could alert clinicians for PTDM risk.