Calcitriol deficiency and 1-year mortality in cardiac transplant recipients.

Background. Administration of the vitamin D hormone calcitriol improves survival in solid-organ transplanted experimental animals. We investigated whether lower serum calcitriol concentrations are associated with increased 1-year mortality in cardiac transplant recipients. Methods. We prospectively recruited 171 patient,; who underwent cardiac transplantation at out institution between May 2004 and April 2006. We assessed calciotropic hormones, inflammation markers, and renal function preoperatively and on postoperative days 6 (t1) and 21 (t2). Results. Serum creatinine and C-reactive protein increased, whereas calcitriol decreased significant after transplantation (P<0.001). As determined by multivariable Cox regression analysis, the calcitriol level at t2 was an independent predictor of 1-year mortality. One-year mortality was 3.7 per 100 person-years in the tertile with the highest calcitriol concentrations at t2 (> 18 pg/mL), 13.2 per 100 person-years in the intermediate tertile (11-18 pg/mL), and 32.1 per 100 person-years in the tertile with the lowest calcitriol concentrations at t2 (<11 pg/mL,) (P<0.001). 25-hydroxyvitamin D deficiency (serum concentrations below 10 ng/mL), renal insufficiency (serum creatinine >= 1.6 mg/dL), and high serum concentrations of the inflammation markers C-reactive peptide and tumor necrosis factor-alpha were predictors of a serum calcitriol concentration below 11 pg/mL (P=0.037-0.001). Conclusions. Low postoperative calcitriol concentrations arc independently associated with high 1-year mortality in cardiac transplant recipients. A causal relationship has yet to be proven by intervention trials using active vitamin D.