Low vitamin D exposure is associated with higher risk of infection in renal transplant recipients

Background Vitamin D is a steroid hormone with multiple vital roles within the immune system. Various studies evaluated the influence of vitamin D on infections postrenal transplantation and found contrasting results. This study aimed to assess the relationship between vitamin D status and the incidence of infection in renal transplant recipients. Methods This is a retrospective cohort study of adult renal transplant recipients at the University of Pittsburgh Medical Center between 2005 and 2012. Patients were grouped as vitamin D sufficient (≥30 ng/mL) or deficient (<30 ng/mL) based on total serum 25-hydroxyvitamin D concentrations. The association between vitamin D levels collected at any point post-transplantation and incidence of infection within ±90 days of the vitamin D levels were assessed using logistic and Poisson's regression models. Results Vitamin D sufficiency at any point post-transplantation was significantly associated with a 66% lower odds (OR: 0.34; 95% CI: 0.22-0.52; P<.001) and 43% lower rate of infections (incident rate ratio (IRR): 0.57; 95% CI: 0.46-0.71; P<.001) within ±90 days of the vitamin D level. Baseline vitamin D level was also associated with lower incidence and risk for infections within the first year post-transplantation. Conclusion Adequate levels of vitamin D in kidney transplant recipients are associated with lower infection risk in the first year and at any time post-transplantation.