Korean J Transplant.  2022 Nov;36(Supple 1):S284. 10.4285/ATW2022.F-4251.

Early posttransplant vitamin D improvement is associated with better long-term kidney graft survival

• Ryu J
• Jeon HJ
• Yang J

• KMID: 2535511
• DOI: http://doi.org/10.4285/ATW2022.F-4251

Abstract

Background
Vitamin D (25-hydroxyvitamin D [25(OH)D]) deficiency in chronic kidney disease is usually ameliorated after kidney transplantation (KT). However, it is not conclusive if the posttransplant vitamin D deficiency is associated with poor graft outcome. This study aimed to investigate the effect of early posttransplant vitamin D status on clinical outcomes.
Methods
The Korean cohort study for outcome in patients with kidney transplantation (KNOW-KT) is a multicenter, observation-al cohort study. A total of 1,034 hundred subjects were included in this study. Annual serum 25(OH)D, 1,25(OH) 2 D 3 , and clinical outcomes, all-cause mortality, cardiovascular event, graft survival, and fracture, were assessed according to vitamin D improvement.
Results
Median follow-up duration was 7.4 years. Serum 25(OH)D levels were increased after KT (before KT, 12.6±7.4 ng/mL; 1 year after KT, 22.6±6.4 ng/mL; 3 years after KT, 24.3±5.8 ng/mL). Vitamin D deficiency was present in 79.1% just before KT. Prev-alence of vitamin D deficiency was decreased after transplantation; however, it was still 38.2% at 7 years after KT. The patients with 25(OH)D improvement 1 year after transplantation showed higher 25(OH)D level than the patients without improvement at any point during follow-up. At 7-year follow-up, higher vitamin D level was associated with vitamin D improvement after KT and vitamin D analog supplementation during 1 year after KT. The 25(OH)D nonimprovement at 1 year after KT was a risk factor for poor graft survival (hazard ratio, 2.408; 95% confidence interval, 1.187–4.886; P=0.013).
Conclusions
The early vitamin D improvement after kidney transplantation was associated with better long-term graft outcome.