Calcitriol deficiency and 1-year mortality in cardiac transplant recipients

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.

We prospectively recruited 171 patients 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).

Serum creatinine and C-reactive protein increased, whereas calcitriol decreased significantly 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 > or = 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).

Low postoperative calcitriol concentrations are 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.