Efficacy and safety of ossein-hydroxyapatite complex versus calcium carbonate to prevent bone loss.

Objective: This study aimed to compare the efficacy and safety of ossein-hydroxyapatite complex (OHC) versus calcium carbonate (CC) for preventing bone loss during perimenopause in current clinical practice.Methods: The prospective, comparative, non-randomized, open-label study included 851 perimenopausal women with basal bone mineral density (BMD) T-score ≥-2 standard deviations (SDs). Participants received either OHC (712 mg calcium/day) or CC (1000 mg calcium/day) over 3 years. BMD was evaluated by dual-energy X-ray absorptiometry at the lumbar spine (L2-L4) at baseline and after 18 and 36 months of follow-up. Adverse drug reactions (ADRs) were also recorded.Results: In women receiving OHC, BMD at the L2-L4 site remained stable over the 3-year follow-up period (mean [SD] change 0.00 [0.11] g/cm2). BMD in the CC arm decreased -3.1% (mean [SD] - 0.03 [0.11] g/cm2). Between-group differences were statistically significant (p < 0.001) and favored OHC. ADRs were more frequent in the CC group (7.7% vs. 2.7% in the OHC group; p = 0.001), affecting primarily the gastrointestinal system.Conclusion: OHC showed greater efficacy and tolerability than CC for bone loss prevention in perimenopausal women in real-world practice. As the daily dose of calcium was higher in the CC group, the differences might be linked to the ossein compound in OHC.