Background Sarcopenia and dynapenia are age-related conditions characterized by reductions in skeletal muscle mass and/or muscle strength. Both conditions are associated with functional decline and impaired quality of life in elderly populations. This study investigated the prevalence and clinical characteristics of sarcopenia, pre-sarcopenia, and dynapenia in elderly patients with osteoporosis. Methodology This cross-sectional study included 332 elderly patients with osteoporosis, including 46 men and 286 women. Participants were classified into the following four groups according to skeletal muscle mass index and grip strength: normal, pre-sarcopenia, dynapenia, and sarcopenia groups. Bone mineral density, body composition, spinal sagittal alignment, vertebral fractures, and low back pain-related clinical outcomes were compared among groups. Results Pre-sarcopenia, dynapenia, and sarcopenia were identified in 42/332 (12.7%), 94/332 (28.3%), and 47/332 (14.2%) patients, respectively. Overall, 183/332 (55.1%) patients demonstrated reduced muscle mass and/or strength. Lower bone mineral density and body mass index were predominantly observed in groups with decreased muscle mass, whereas poorer low back pain-related outcomes were mainly associated with reduced muscle strength. Conclusions A substantial proportion of elderly patients with osteoporosis demonstrated impaired muscle mass and/or muscle strength. Muscle mass appeared to be associated with bone density and body composition, whereas muscle strength was more closely related to trunk muscle mass and low back pain-related disability.
Miyagi et al. (Thu,) studied this question.