Received on October 28, 2008
Accepted on March 19, 2009

Endocrinology and Metabolism

Circulating Calcitriol Concentrations and Total Mortality

¹ Department of Cardio-Thoracic Surgery, Heart Center North Rhine-Westfalia, Ruhr University Bochum, Bad Oeynhausen, Germany
² Institute for Laboratory and Transfusion Medicine, Heart Center North Rhine-Westfalia, Ruhr University Bochum, Bad Oeynhausen, Germany

^* To whom correspondence should be addressed. E-mail: azittermann{at}hdz-nrw.de.

BACKGROUND: Evidence is accumulating that vitamin D supplementation of patients with low 25-hydroxyvitamin D concentrations is associated with lower cardiovascular morbidity and total mortality during long-term follow-up. Little is known, however, about the effect of low concentrations of the vitamin D hormone calcitriol on total mortality. We therefore evaluated the predictive value of circulating calcitriol for midterm mortality in patients of a specialized heart center.

METHODS: This prospective cohort study included 510 patients, 67.7% with heart failure (two-thirds in end stage), 64.3% hypertension, 33.7% coronary heart disease, 20.2% diabetes, and 17.3% renal failure. We followed the patients for up to 1 year after blood collection. For data analysis, the study cohort was stratified into quintiles of circulating calcitriol concentrations.

RESULTS: Patients in the lowest calcitriol quintile were more likely to have coronary heart disease, heart failure, hypertension, diabetes, and renal failure compared to other patients. They also had low 25-hydroxyvitamin D concentrations and high concentrations of creatinine, C-reactive protein, and tumor necrosis factor . Eighty-two patients (16.0%) died during follow-up. Probability of 1-year survival was 66.7% in the lowest calcitriol quintile, 82.2% in the second quintile, 86.7% in the intermediate quintile, 88.8% in the fourth quintile, and 96.1% in the highest quintile (P < 0.001). Discrimination between survivors and nonsurvivors was best when a cutoff value of 25 ng/L was applied (area under the ROC curve 0.72; 95% CI 0.66–0.78).

CONCLUSIONS: Decreased calcitriol levels are linked to excess midterm mortality in patients of a specialized heart center.