AUTHOR=Zeng Shufei , Yang Yide , Li Shuping , Hocher Carl-Friedrich , Chu Chang , Wang Ziqiang , Zheng Zhihua , Krämer Bernhard K. , Hocher Berthold 

TITLE=25(OH)D-but not 1,25(OH)2D–Is an independent risk factor predicting graft loss in stable kidney transplant recipients

JOURNAL=Frontiers in Medicine

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2023.1141646

DOI=10.3389/fmed.2023.1141646

ISSN=2296-858X

ABSTRACT=Vitamin D deficiency (VDD) or vitamin D insufficiency is common in kidney transplant recipients (KTRs). The impact of VDD on clinical outcomes in KTRs remain poorly defined and the most suitable marker for assessing vitamin D nutritional status in KTRs is unknown so far.  We conducted a prospective study including 600 stable KTRs (367 men, 233 women) and a meta-analysis to pool existing evidence to determine whether 25(OH)D or 1,25(OH)2D predicted graft failure and all-cause mortality in stable KTRs.  Compared with a higher 25(OH)D concentration, a low concentration of 25(OH)D was a risk factor for graft failure (HR 0.946, 95%CI 0.912-0.981, p=0.003), whereas 1,25 (OH)2D was not associated with the study end-point graft loss (HR 0.993, 95%CI 0.977-1.009, p=0.402). No association was found between either 25(OH)D or 1,25 (OH)2D and all-cause mortality. We furthermore conducted a meta-analysis including 8 studies regarding the association between 25(OH)D or 1,25(OH)2D and graft failure or mortality, including our study. The meta-analysis results were consistent with our study in finding that lower 25(OH)D levels were significantly associated with the risk of graft failure (OR=1.04, 95%CI: 1.01-1.07), but not associated with mortality (OR=1.00, 95%CI: 0.98-1.03). Lower 1,25(OH)2D levels were not associated with the risk of graft failure (OR=1.01, 95%CI: 0.99-1.02) and mortality (OR=1.01, 95%CI: 0.99-1.02). 
In conclusions, baseline 25(OH)D concentrations but not 1,25(OH)2D concentrations were independently and inversely associated with graft loss in adult KTRs.