Vitamin D Levels After Kidney Transplantation and the Risk of Cytomegalovirus Infection

BACKGROUND: Some studies reported an association between low levels of vitamin D and the risk of infections, especially viral infections. Kidney transplant patients are at risk of opportunistic infections; however, no study has been conducted on the association between vitamin D levels and the risk of CMV infection. OBJECTIVES: The aim of this study was to compare the level of vitamin D in two groups of patients with and without CMV infection within four months after the transplantation. Moreover, we aimed to find a relation between vitamin D level, before and after transplantation in each group. PATIENTS AND METHODS: This prospective cohort study was conducted in Baqiyatallah hospital in Tehran in 2013. A total of 82 kidney transplant patients were enrolled and vitamin D levels were measured in them before transplantation. The kidney transplant patients had been followed up for four months and monitored for the presence of cytomegalovirus antigen (CMV Ag) in their blood. In patients with positive CMV Ag, vitamin D level was measured again when they became positive but in other patients it was measured at the end of follow-up; at the end, characteristics of patients and vitamin D levels were compared between the two groups. RESULTS: Of all, 40 patients were CMV Ag positive and 42 patients were negative. In most patients transplanted organs were taken from cadaver (66%) and the most common type of dialysis was hemodialysis (92%). Most participants did not undergo antithymocyte globulin therapy (69%) and pulse corticosteroid therapy (83%). Vitamin D level before transplantation was 17.2 ± 11.6 ng/mL. In patients with positive results or at the end of follow-up in patients without CMV Ag, vitamin D level was 16.3 ± 11.4 ng/mL. Only 11% of kidney transplant patients, within four months after transplantation, had a normal level of vitamin D (> 30 ng/mL). There was no significant difference between the two groups for patients’ characteristics (P > 0.05). Vitamin D levels, before transplantation and at the time of detecting CMV Ag or at the end of follow-up period in patients without CMV, were not significantly different between the two groups (P > 0.05). However, vitamin D levels decreased in patients with CMV, while it increased in CMV Ag negative patients, which was statistically significant (P = 0.037). CONCLUSIONS: Only 11% of kidney transplant patients, even with a successful transplantation of the kidney and with an acceptable performance of the transplanted kidney, had an adequate level of vitamin D. Although, we did not find any significant association between vitamin D levels and CMV infection during a 4-month follow-up after kidney transplantation. It was observed that, compared with the time before transplantation, vitamin D levels decreased in patients with CMV, while it increased in CMV negative patients.