Comparison of the effects of ossein-hydroxyapatite complex and calcium carbonate on bone metabolism in women with senile osteoporosis: a randomized, open-label, parallel-group, controlled, prospective study.

BACKGROUND AND OBJECTIVE: Calcium and vitamin D supplementation is recommended in patients with osteopenia and osteoporosis. One group that could benefit from this treatment is women with senile osteoporosis. Two sources of supplementary calcium are ossein-hydroxyapatite complex (OHC) and calcium carbonate, but, to date, their comparative effects on bone metabolism have not been studied in women with senile osteoporosis. The objective of this study was to compare the effects of OHC and calcium carbonate on bone metabolism in women with senile osteoporosis. METHODS: This was a randomized, open-label, parallel-group, controlled, prospective study to compare the effects of OHC (treatment group) and calcium carbonate (control group) on bone metabolism. Patients were included between 2000 and 2004 and followed up for a maximum of 3 years. The study was carried out at the bone metabolism unit of two university hospitals in Barcelona, Spain. Subjects were women aged >65 years with densitometric osteoporosis of the lumbar spine or femoral neck. The treatment group received open-label OHC (Osteopor®) at a dose of two 830 mg tablets every 12 hours (712 mg elemental calcium per day). The control group received open-label calcium carbonate at a dose of 500 mg of elemental calcium every 12 hours (1000 mg elemental calcium per day). Both groups also received a vitamin D supplement (calcifediol 266 µg) at a dose of one vial orally every 15 days. Biochemical markers of bone remodelling (osteocalcin by electrochemiluminescence, tartrate-resistant acid phosphatase using colorimetry) were measured at baseline and annually for 3 years. Bone mineral density (BMD) at the lumbar spine and femoral neck was also measured. RESULTS: One hundred and twenty women were included (55 in the OHC group and 65 in the calcium carbonate group), of whom 54 completed 3 years of follow-up. Levels of serum osteocalcin increased to a greater extent in the OHC group compared with the calcium carbonate group (by a mean ± SD of 0.84 ± 3.13 ng/mL at year 2 and 1.86 ± 2.22 ng/mL at year 3 in the OHC group compared with a mean ± SD decrease of 0.39 ± 1.39 ng/mL at year 2 and an increase of 0.31 ± 2.51 ng/mL at year 3 in the calcium carbonate group); the differences between treatment groups were statistically significant (p < 0.05) at both years. Changes over time in serum osteocalcin level were also statistically significant (p < 0.05) in the OHC group, but not in the calcium carbonate group. Changes in mean BMD at the lumbar spine and femoral neck between baseline and year 3 were -1.1% and 2.5% for OHC and -2.3% and 1.2% for calcium carbonate, respectively. CONCLUSION: OHC had a greater anabolic effect on bone than calcium carbonate.

Calcium citrate and vitamin D in the treatment of osteoporosis.

The combination of calcium with vitamin D (vitamin D(3) [colecalciferol]) forms the basis of preventive and therapeutic regimens for osteoporosis. A number of studies have suggested that the combination of calcium and vitamin D is effective when administered at respective dosages of at least 1200 mg and 800 IU per day, although efficacy is, as expected, affected by patient compliance. Overall, treatment with this combination appears to be effective in reducing the incidence of non-vertebral and hip fractures. Also, in all drug studies (of antiresorptive and anabolic agents and strontium ranelate) that demonstrated a reduction in risk of osteoporotic fractures, patients also took calcium and vitamin D supplements. An important finding in this regard is that vitamin D levels have been demonstrated to be inadequate in more than half of women treated for osteoporosis in the US and Europe. The capacity of the small intestine to absorb calcium salts depends on the solubility and ionization of the salts. These properties vary for different salts, with fasting calcium citrate absorption being greater than that of calcium lactogluconate and calcium carbonate. Calcium citrate formulations taken between meals may help to prevent abdominal distension and flatulence, as well as minimize the risk of renal calculus formation, thus helping to optimize patient compliance. Therefore, calcium citrate combined with vitamin D is the combination of choice for the prevention or treatment of osteoporosis.

Efficacy of ossein-hydroxyapatite complex compared with calcium carbonate to prevent bone loss: a meta-analysis.

OBJECTIVE: There is increasing evidence to suggest that ossein-hydroxyapatite complex (OHC) is more effective than calcium supplements in maintaining bone mass. The aim of this meta-analysis was to determine whether OHC has a different clinical effect on bone mineral density (BMD) compared with calcium carbonate (CC). METHODS: A meta-analysis of randomized controlled clinical trials was carried out to evaluate the efficacy of OHC versus CC on trabecular BMD. We identified publications on clinical trials by a search of electronic databases, including MEDLINE (1966-November 2008), EMBASE (1974-November 2008), and the Cochrane Controlled Clinical Trials Register.The primary endpoint was percent change in BMD from baseline. Data were pooled in a random-effects model, and the weighted mean difference was calculated. A sensitivity analysis that excluded trials without full data was performed. RESULTS: Of the 18 controlled trials initially identified, 6 were included in the meta-analysis. There was no significant heterogeneity among the included trials. The percent change in BMD significantly favored the OHC group (1.02% [95% CI, 0.63-1.41], P < 0.00001). These results were confirmed in the sensitivity analysis. CONCLUSIONS: OHC is significantly more effective in preventing bone loss than CC.