Minimal Detectable Changes in the Five Times Sit-to-Stand Test in Older Japanese Adults with Sarcopenia Requiring Long-Term Care

Background and Objectives: Although the importance of sarcopenia control has been suggested, there are no minimal detectable change (MDC) studies of older adults with sarcopenia, to our knowledge, and the criteria for determining the effectiveness of interventions are unknown. The purpose of this study was to calculate the MDC in the five times sit-to-stand test (FTSST) in older Japanese adults with sarcopenia and use it as an index to determine the effectiveness of future interventions. Materials and Methods: This was a cross-sectional study conducted in January and February 2023. The participants of this study were older Japanese adults using daycare rehabilitation. Thirty-eight participants performed the FTSST twice a week. Grip strength, walking speed, and skeletal muscle mass were measured to determine the presence of sarcopenia. The diagnosis of sarcopenia was defined as low skeletal muscle mass and low muscle strength and/or low physical function, based on the Asian Working Group for Sarcopenia 2019 diagnostic criteria. Participants were further classified as sarcopenic or non-sarcopenic. Intraclass correlation coefficients (ICCs) and MDCs were calculated for the overall, sarcopenia, and non-sarcopenia groups using the two FTSST measures. The average and difference of the two variables were used to calculate the MDC. Results: Overall, the ICC (1,1) was 0.94, MDC was 2.87 s, and MDC% was 23.3%. The sarcopenia group had an ICC (1,1) of 0.93, MDC of 3.12 s, and MDC% of 24.0%. The non-sarcopenia group had an ICC (1,1) of 0.95, MDC of 2.25 s, and MDC% of 19.2%. Conclusions: Despite the limitation of the data being only from this study population, we found that a change of ≥3.12 s or ≥24.0% in the FTSST of older adults with sarcopenia was clinically meaningful and may help to determine the effectiveness of sarcopenia treatment. The improvement or decline in older Japanese adults with sarcopenia should be determined by changes in the FTSST over a longer period of time than that for other conditions.