Predictive Factors for Increased Bone Density Following Romosozumab Administration Based on Pre-Administration Blood Test Results.

Purpose: Romosozumab reportedly increases bone density in patients with severe osteoporosis; however, data on its clinical effects are limited. We conducted a multicenter retrospective survey to study the bone density-increasing effects of romosozumab and blood test-based predictive factors in patients with severe osteoporosis, examining its effects in clinical practice.

Materials and methods: This was a multicenter retrospective observational study. The subjects were patients with severe osteoporosis who were treated with romosozumab at the participating facilities. The increase in bone density was assessed by comparing bone density changes (as a percentage) in the lumbar spine, femoral neck, and total femur before and 12 months after administration using dual-energy X-ray absorptiometry. The association between changes in bone density at each site and pre-treatment bone metabolism markers (Tracp 5b, P1NP), serum calcium levels, nutritional status [Conut score: albumin, total cholesterol (T-Cho), and total lymphocyte count], and kidney function (eGFR) was assessed.

Results: In both naïve patients and those switching from bone resorption inhibitors, the bone density increased significantly. In naïve patients, eGFR were positively associated with bone density in the total femur. In cases of switching from bone resorption inhibitors, correlations were found between Tracp 5b and lumbar spine bone mineral density (BMD), as well as between Tracp 5b, Alb, T-Cho, and eGFR in the total femur BMD.

Conclusion: Romosozumab administration significantly increases bone density in osteoporosis, and assessing key predictive factors is necessary to ensure clinical effectiveness.