Dynamic conversion and associated risk factors between mutually exclusive muscle health states in geriatric...

The loss of muscle mass plus a decrease in muscle function is composed of sarcopenia. Before entering this muscle health status, individuals experience either low muscle quantity or poor muscle quality. The natural course of the dynamic transition to sarcopenia from robust through these two mutually exclusive muscle health statuses is presently unclear.

Adults aged 65 years and older living in the community and who received annual health examinations, including muscle function, body composition and other measurements, were enrolled. Participants with normal muscle mass and function were considered robust. Presarcopenia is defined as the sole loss of muscle mass; dynapenia is indicated as poor muscle function but reserve normal muscle mass, and these two statuses are mutually exclusive to muscle health. Sarcopenia is characterized as a double reduction in muscle mass and muscle function. We investigated the trajectory of muscle health transition to sarcopenia from dynapenia and presarcopenia and estimated the possibility of recovery from dynapenia and presarcopenia. The relationships between muscle health transition and different determinants among older adults were examined.

In total, 296 participants were included in the analysis. Older adults with dynapenia have more chronic diseases and higher obesity parameters. Individuals with presarcopenia tended to have a higher hazard ratio (HR) for progression to sarcopenia (HR = 4.20, 95% confidence interval [CI] = 2.59-6.81). A higher body fat percentage and fat-to-muscle ratio are associated with the transition to sarcopenia. Dynapenic individuals had a higher HR for recovery to a robust status (HR = 4.18, 95% CI = 2.13-8.19). Greater muscle mass, greater handgrip strength, and higher albumin levels were associated with a greater likelihood of recovery to a more normal muscle health.

Dynapenia and presarcopenia, which are mutually exclusive muscle health conditions, tended to be associated with different muscle health transitions. Early recognition of and intervention in vulnerable elderly individuals are necessary to prevent the progression of sarcopenia.