Phenotype validation of the Korean working group on sarcopenia guideline

This study aimed to validate the proposed Korean Working Group on Sarcopenia (KWGS) guideline, which introduces the concept of functional sarcopenia, in older Korean adults.

Data from the Aging Study of Pyeongchang Rural Area, a longitudinal cohort of community-dwelling older adults, were utilized to compare frailty status and institutionalization-free survival among participants according to sarcopenia status. Based on the KWGS guideline, severe sarcopenia was defined as low muscle mass and strength with slow gait speed; sarcopenia (not severe) was defined as low muscle mass with low muscle strength or slow gait speed; and functional sarcopenia was defined as low muscle strength and slow gait speed without low muscle mass.

Among the 1302 participants, 329 (25.3 %) had severe sarcopenia, 147 (11.3 %) had sarcopenia (not severe), and 277 (21.3 %) had functional sarcopenia. Frailty was significantly greater in participants with any phenotype of sarcopenia than in those without sarcopenia. Additionally, participants with functional sarcopenia were frailer than those with sarcopenia (not severe). Furthermore, the rates of institutionalization and mortality were higher in participants with any phenotype of sarcopenia than in those without sarcopenia. There was no statistical difference between the rates of sarcopenia (not severe) and those with functional sarcopenia. These findings remained consistent after adjusting for age and sex.

Each phenotype according to the KWGS guideline was associated with significantly greater frailty and increased risk of institutionalization and mortality. Functional sarcopenia was associated with greater frailty and had comparable prognosis with sarcopenia (not severe).