In patients with chronic heart failure, the vitamin D metabolite 1,25-dihydroxyvitamin D (1,25(OH)2D), also called calcitriol, and its ratio to parathyroid hormone (PTH 1-84) may help predict cardiovascular death.

Heart failure, with high morbidity and mortality, is increasingly prevalent worldwide, and biomarkers may help doctors predict heart failure and help patients survive and patients with decreased calcitriol and decreased ratio of calcitriol to PTH might benefit from more aggressive supplementation.

Scientists at the Cliniques Universitaires Saint Luc (Brussels, Belgium) investigated 170 chronic heart failure patients. Overall, 36 patients were female, 134 patients were male, and the average age was 67 years. Their overall mean ejection fraction was 23%, and the origin of heart failure was ischemic in 119 patients and dilated cardiomyopathy in 51 patients. The team examined the ability of calcitriol and its ratio with PTH(1-84) to predict cardiovascular death in chronic heart failure, and determined the patients' calcitriol and PTH(1-84) levels at baseline. The 1,25(OH)2D was measured by a fully automated LIAISON XL 1,25 Dihydroxyvitamin D assay (DiaSorin; Saluggia, Italy).

The investigators found that serum calcitriol levels decreased markedly according to heart failure severity, and that decreased ratios of calcitriol to PTH(1-84) were significantly related to heart failure severity. After eight years of follow-up, the calcitriol and the ratio of calcitriol to PTH(1-84) were strongly able to predict the deaths of 106 patients who died from cardiovascular causes. In patients with heart failure, vitamin D deficiency and hyperparathyroidism are common, and evidence is growing for the role of vitamin D and PTH in worsening heart failure.

Damien Gruson, PhD, professor and associated laboratory director in the Department of Laboratory Medicine and lead study author, said, “We were surprised by the strong predictive power of 1,25(OH)2D and its ratio to 1-84 PTH. It is noteworthy that in this study the 1,25(OH)2D was measured by a novel extraction-free, fully automated assay based on an unique murine monoclonal antibody, which recognizes the conformational change induced by the binding of the 1,25(OH)2D to a recombinant fusion protein. Our results can provide physicians with a new tool - the 1,25(OH)2D to PTH ratio - to risk stratify heart failure patients.” The study was presented at the annual meeting of the Endocrine Society, ENDO 2015 held March 5-8, 2015, in San Diego (CA, USA).

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Cliniques Universitaires Saint Luc
DiaSorin