Introduction

Low levels of serum vitamin D are common and associated adverse renal outcomes. The frequency of hypovitaminosis D following kidney transplantation (KT) is not well studied. We examined vitamin D levels changes following KT, and compared the changes between patients with low-and normal-vitamin D pre-Tx.

Materials and methods

We studied KT recipients at UCLA from January 1, 2006, to May 31, 2016, who had 25-OH vitamin D tests both before and within the first year of KT. The value closest to the transplant date was used to define pre-Tx and post-Tx vitamin D levels. Patients were divided into two groups according to vitamin D levels, 1) low (<30) and 2) normal (30-50). Patients with vitamin D levels >50 were excluded. Mean vitamin D levels were compared between pre-and post-Tx using t-test analysis.

Results

A total of 398 patients were included in this study. We found that 315 patients (79.15%) had low vitamin D levels and 83 patients (20.85%) had normal vitamin D levels pre-Tx. Mean pre-and post-Tx vitamin D levels were 21.12 and 20.39 ng/mL, respectively. Post-Tx vitamin D levels were 23.13 and 19.67 ng/mL, respectively (p<0.01). Patients with low pre-Tx vitamin D levels were more likely to have low post-Tx vitamin D levels (p=0.03). Furthermore, 60.5% of patients with decreasing post-Tx vitamin D levels had low pre-Tx vitamin D levels and patients with normal pre-Tx vitamin D levels had a greater relative reduction in vitamin D levels following KT.

Conclusions

Hypovitaminosis D was very common in KT recipients. Preexisting hypovitaminosis D patients were more likely to have persistent low vitamin D levels post-Tx. Moreover, post-Tx vitamin D levels were lower than normal values regardless of pre-Tx vitamin D levels. Future studies should include vitamin D supplement and graft survival to support how vitamin D may impact on long-term outcome.

CITATION INFORMATION: Lum E., Phonphok K., Datta N., Bunnapradist S. Changes in Vitamin D Levels after Kidney Transplantation Am J Transplant. 2017;17 (suppl 3).

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