Calf circumference predicts changes of bone mineral density in postmenopausal osteoporotic women receiving denosumab

Background: Aging is associated with deterioration of muscle and bone health, resulting in increased fragility fracture risk. It is not known whether muscle mass and strength could impact the osteoporosis pharmacological response. Aim: The aim of this study was to analyze the association between muscle mass and strength with the response to denosumab in osteoporosis. Methods: Postmenopausal women at high fracture risk receiving denosumab (60 mg subcutaneously administered every 6 months) were considered. The likelihood of sarcopenia was estimated by administering the SARC-F questionnaire, muscle mass and performance were assessed by measuring calf circumference (CC) and hand grip strength, respectively. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. Results: 130 women (age 70.2 ± 9.4 years) were recruited. Baseline BMD T-score values were - 2.6 ± 1.1 SD and - 2.3 ± 0.7 SD at lumbar spine and femoral neck, respectively; while CC and grip strength were 31.9 ± 2.9 cm and 22.7 ± 6.7 kg, respectively. The SARC-F score was associated with the 10-year probability of major osteoporotic fracture (r = 0.21, p < 0.05). The CC was positively associated with the T-score values of both lumbar spine (r = 0.262, p = 0.034) and femoral neck (r = 0.359, p = 0.004). Denosumab administration (treatment duration 43 months), lead to BMD improvement by + 9.6% at the lumbar spine and + 7.3% at the femoral neck (pall < 0.05). After adjustment for comorbidities, fracture risk and treatment duration, the CC (β = 1.76, SE = 0.82, p = 0.03) and the baseline femoral BMD (β = - 94.19, SE = 26.09, p = 0.0009) were independently associated with femoral BMD gain over time. Conclusion: In postmenopausal osteoporotic women, the CC was positively and independently associated with denosumab treatment response.