Association between Skeletal Muscle Mass Index and Convalescent Rehabilitation Ward Achievement Index in Older Patients.

Objective: The aim of the current study was to investigate the association between the skeletal muscle mass index (SMI) and the convalescent rehabilitation ward achievement index (CRWAI) in older patients with functional impairment.

Methods: We conducted a retrospective cohort study at a single rehabilitation center in Japan to include patients admitted to the convalescent rehabilitation ward because of neurological disease, motor disorder, or disuse syndrome. Patients with missing SMI data, those who died or were transferred to other hospitals due to comorbidities, those aged less than 65 years, and those hospitalized for <7 days were excluded from the study. We divided patients into two groups based on their SMI - the high SMI group (SMI ≥7.0 kg/m in men and SMI ≥5.7 kg/m in women) and the low SMI group (SMI <7.0 kg/m in men and SMI <5.7 kg/m in women); we then evaluated the association between SMI and the CRWAI score.

Results: Of the 319 recruited patients, 84 (26%) were in the high SMI group. The medians and interquartile ranges of the CRWAI scores in the high SMI and low SMI groups were 38.6 (23.1-61) and 31.8 (10.1-57.5), respectively (P=0.029). A high SMI was independently and negatively associated with the CRWAI score (β=- 0.16, P=0.014).

Conclusions: Our study showed that a high SMI was an independent factor negatively influencing the CRWAI score in older patients in a convalescent rehabilitation ward.