Real-World Evaluation of 12-Month Romosozumab Treatment in Korean Women with Severe Osteoporosis: Potential Synergy with Hormone Therapy

Background/Objectives: Osteoporosis is a major public health concern, due to its high risk of fractures and disability and associated medical costs. Romosozumab, an anabolic agent, has been approved for the treatment of osteoporosis in postmenopausal women at high risk of fractures. However, limited data exist on its long-term effects in the Korean population, particularly regarding its impact on bone mineral density (BMD), bone turnover markers, and body composition. This study aimed to evaluate the 12-month effects of romosozumab treatment on BMD, bone turnover markers, and body composition in postmenopausal Korean women with high-fracture-risk osteoporosis (T-scores ≤ −3.0). Additionally, the impact of concomitant postmenopausal hormone therapy (MHT) on BMD changes was assessed. Methods: This multicenter, retrospective observational study included 50 postmenopausal women diagnosed with osteoporosis (T-scores ≤ −3.0) who received 12 monthly doses of romosozumab (210 mg) at two hospitals in Korea. Changes in BMD in the lumbar spine, femoral neck, and total hip were assessed using dual-energy X-ray absorptiometry (DXA). Bone turnover markers, including procollagen type 1 N-terminal propeptide (P1NP) and C-terminal telopeptide of type 1 collagen (CTX), were measured at baseline and at 3, 6, and 12 months. Changes in body composition, including the skeletal muscle index (SMI), body mass index (BMI), and visceral adipose tissue (VAT), were also analyzed. Results: After 12 months of romosozumab treatment, BMD significantly increased at the lumbar spine (14.65%), femoral neck (6.58%), and total hip (4.19%) (p < 0.05). P1NP levels increased significantly at 3 months (+37.9%), but returned to baseline at 6 months, while CTX levels continuously decreased (−27.8%) over 12 months. No significant changes were observed in SMI or BMI, but the VAT showed a slight decreasing trend (p < 0.05). Additionally, patients receiving concomitant MHT demonstrated a significantly greater increase in lumbar spine BMD compared to those receiving romosozumab alone (p < 0.05), while no significant differences were observed in femoral neck and total hip BMD. Conclusions: This study demonstrated that 12 months of romosozumab treatment significantly improved BMD and bone turnover markers in postmenopausal Korean women with severe osteoporosis. The combination of romosozumab and MHT further enhanced lumbar spine BMD gains. These findings support the use of romosozumab as an effective treatment for high-risk osteoporotic fractures in postmenopausal Korean women, and suggest potential benefits of a combined therapeutic approach.