A retrospective comparative study on the effects of denosumab combined with calcium and vitamin D versus calcium and vitamin D alone on bone remodeling markers in patients with osteoporotic fractures

This study aims to compare and analyze the effects of denosumab combined with calcium and vitamin D versus calcium and vitamin D alone on bone remodeling markers and bone mineral density (BMD) in patients with osteoporotic fractures. This single-center retrospective comparative study included patients with osteoporotic fractures admitted between January 2022 and January 2024. According to the treatment regimen, patients were divided into the denosumab group (subcutaneous denosumab every 6 months plus oral calcium and vitamin D supplementation) and the calcium plus vitamin D (CaD) group (oral calcium and vitamin D supplementation only). Propensity score matching was used to balance baseline characteristics, with 60 cases in each group. Bone remodeling markers (β-isomerized C-terminal telopeptide of type I collagen [β-CTX], procollagen type I N-terminal propeptide [P1NP], bone-specific alkaline phosphatase, osteocalcin), BMD changes, and safety profiles were compared between the 2 groups before treatment, and at 6 and 12 months after treatment. After treatment, the levels of the bone resorption marker β-CTX and the bone formation marker P1NP were significantly reduced in the denosumab group, and remained significantly lower than those in the CaD group at all time points (time, group, and interaction effects all P < .001). After 12 months of treatment, BMD increases in the lumbar spine and femoral neck were 8.8% and 7.3% respectively in the denosumab group, significantly higher than in the CaD group (2.6% and 2.2%) ( P < .01 for both group and interaction effects). Correlation analysis showed that in the denosumab group, the decreases in β-CTX and P1NP were significantly negatively correlated with BMD improvements in the lumbar spine and femoral neck ( r = –0.33 to –0.42, P < .05). The overall incidence of adverse events did not differ significantly between the 2 groups (13.3% vs 8.3%, P > .05), and all events were mild. For patients with osteoporotic fractures, denosumab combined with calcium and vitamin D supplementation is more effective in suppressing bone turnover and improving bone mineral density than calcium and vitamin D alone, without increasing significant safety risks. Bone remodeling markers β-CTX and P1NP may serve as potential reference indicators for evaluating the therapeutic efficacy of denosumab.