Sarcopenia as a Stronger Predictor for All-Cause Mortality Than Osteoporosis in a Medical Center in Central Taiwan.

Purpose: Sarcopenia (SP) and osteoporosis (OP) both pose higher risks for adverse health outcomes. This study explored the relationship among sarcopenia, osteoporosis and all-cause mortality. Patients and Methods: This retrospective cohort utilized a tertiary-hospital-based cohort during the years from 2018 to 2024. Patients received dual-energy X-ray absorptiometry scans. Osteoporosis was diagnosed when T-scores of <-2.5 were determined at the L-spine or femoral neck. Sarcopenia was defined using the Asian Working Group for Sarcopenia 2019 criteria: low muscle strength, low physical performance, and a low appendicular skeletal mass index. We utilized the Cox proportional hazard model and Kaplan-Meier curves to depict observed time to mortality. Post-hoc analysis was applied for subgroup comparison and statistical power calculation. Interaction terms sensitivity analysis was used for analyzing mutually exclusive groups. Results: A total of 545 patients (median age [interquartile range] 68.7 [52.8-80.7] years; 72.3% women) were analyzed. At baseline, 15.6% had SP alone, 23.1% had OP alone, and 14.3% had both conditions. Over median 0.7 (interquartile range = 0.2-1.4) years of follow-up, 24 deaths occurred. Older age, multimorbidity, sarcopenia, and osteoporosis were significantly associated with higher mortality. In multivariable analysis adjusting for age and multimorbidity, sarcopenia alone was a stronger predictor of mortality compared to osteoporosis alone (hazard ratio [HR] 7.34 vs 3.99), and the mortality HR was 7.34 for sarcopenia with or without osteoporosis higher than 3.99 for osteoporosis with/without sarcopenia. Interaction analysis was not feasible in the four-group comparison, as the interaction term overlapped with the 'both sarcopenia and osteoporosis' group; in the other three groups, the SP×OP interaction was not significant. SP patients were more likely to be older, male, and have lower body mass index, total tissue, and lean mass. Conclusion: These findings suggest that sarcopenia may be a more important predictor of mortality than osteoporosis in patients, highlighting the need for muscle health assessment.