Impaired bone metabolism is a frequent complication following
heart transplantation. Little is known, however, about possible alterations in bone turnover of pretransplant patients with
congestive heart failure (CHF). We therefore studied
biomarkers of bone turnover in 21 male patients with CHF (New York Heart Association [NYHA] classification > II) compared with 21 controls (NYHA classification < II).
Biomarkers of bone formation (intact
osteocalcin and carboxy-terminal propeptide of
type I collagen), markers of
bone resorption (
N-telopeptide and
C-telopeptide of
type I collagen), undercarboxylated
osteocalcin (an
indicator of fracture risk), and concentrations of
calcium,
parathyroid hormone, and
vitamin D metabolites (25-hydroxyvitamin D and
calcitriol) were measured in fasting blood samples. Serum levels of intact
osteocalcin were 44.5% lower (P < 0.01), and the ratio of undercarboxylated-to-intact
osteocalcin was 113% higher (P < 0.01) in the patients in comparison with the controls. Moreover, patients had 34% lower
25-hydroxyvitamin D levels (P < 0.01) and 22% lower
calcitriol levels (P < 0.05) than the controls. The
bone resorption markers,
N-telopeptide and
C-telopeptide; the bone formation marker, carboxy-terminal propeptide of
type I collagen;
parathyroid hormone levels; and
albumin-adjusted serum
calcium concentrations did not differ between patients and controls (all P values > 0.05). In summary, there were no biochemical signs of enhanced bone
collagen resorption in pretransplant CHF patients. However, the low serum levels of intact
osteocalcin and the high ratio of undercarboxylated-to-intact
osteocalcin deserve further consideration.