Vitamin D levels and their relationship with cardiac biomarkers in chronic hemodialysis patients.

Vitamin D insufficiency may be associated with cardiovascular (CV) mortality in HD patients. To test this hypothesis, we cross-sectionally measured 25-hydroxyvitamin D (25D), 1,25-dihydroxyvitamin D (1,25D), cardiac troponin T (cTnT), and N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) in chronic HD patients. Sixty-five patients (M:F=31:34, age 52.2+/-13.2 yr, DM 41.5%) were selected. Along with the expected low levels of 1,25D, 59 (90.8%) patients had 25D insufficiency (<30 ng/mL) among whom 15 (23.1%) were 25D deficient (<10 ng/mL). The 25D levels showed a negative correlation with cTnT levels (Spearman's rho=-0.44, p<0.01) but not with NT-pro-BNP levels (Spearman's rho=-0.17, p=0.17). The 1,25D levels, however, did not show any relationship with either cTnT or NT-pro-BNP. In multivariate analysis, being male and having low levels of 25D were independent risk factors associated with cTnT elevation (beta=0.44, p<0.01 and beta=-0.48, p<0.01, respectively). In conclusion, not only 1,25D but also 25D are commonly decreased in HD patients. Lower 25D levels appear to be associated with cTnT elevation, predicting worse CV outcome, and are possible to involve cardiac hypertrophy or coronary artery disease.