Effects of calcium supplementation on bone loss and fractures in congestive heart failure.

Background: Cross-sectional studies have shown that more than 50% of patients with congestive heart failure (CHF) have decreased bone mineral density (BMD). There is limited knowledge about the longitudinal changes of BMD and how to treat bone loss in patients with CHF.

Methods: The present study was a prospective, longitudinal trial in which 33 male patients with CHF (ejection fraction (EF): 30+/-11%) were assigned to 1000 mg calcium supplementation or no supplementation. BMD was measured at the lumbar spine (LS) and the femoral neck (FN) by dual-energy X-ray absorptiometry at baseline and after 12 months.

Results: Osteopenia (LS 33% and FN 36%) and osteoporosis (LS 15% and FN 6%) were frequently seen in these patients; 70% showed impaired renal function, 42% secondary hyperparathyroidism, and 33% hypogonadism. Bone resorption markers were strongly elevated and correlated negatively with the EF. Patients without calcium supplementation revealed a reduction of BMD (LS 1.7% and FN 1.9%) within 12 months. The fracture incidence was 6%. Patients with calcium supplementation also demonstrated a 6% fracture incidence and a decrease in BMD (LS 1.2% and FN 1.6%), which was not significantly different from the untreated group. Loss of BMD at FN was only seen in patients with impaired renal function.

Conclusions: Patients with CHF demonstrate a progressive decrease in BMD when compared with age-matched healthy individuals. Increased bone resorption due to renal insufficiency with consecutive secondary hyperparathyroidism is a main reason for BMD loss in CHF. Calcium supplementation alone cannot sufficiently prevent the decrease in BMD.