The clinical usefulness of muscle mass and strength measures in older people: a systematic review

BACKGROUND: sarcopenia is the loss of muscle mass and quality and is diagnosed using measures of muscle strength, size and mass. We evaluated the literature on whether sarcopenia measures are predictive of motor outcomes in older people in clinical settings. METHODS: electronic databases (MEDLINE Ovid, EMBASE, CINAHL and Web of Science) were searched for articles on measures of muscle mass, volume, thickness or strength, in older people in clinical settings, which reported cross-sectional or longitudinal associations with motor outcomes. Clinical cohorts included geriatric medical inpatients and outpatients, patients with hip fracture, geriatric rehabilitation and care home residents. Motor outcomes were mobility, falls, balance and activities of daily living (ADL). Due to high study heterogeneity, standardised mean differences were used to compare strength of associations. RESULTS: in total, 83 articles were identified. The most frequently studied measures were grip strength (47 studies), knee extension strength (21 studies) and bioelectrical impedance analysis (18 studies). Handgrip strength (HGS) had evidence for cross-sectional associations with mobility (14 of 16 studies, 2,088 participants), balance (6 of 6 studies, 1,177 participants) and ADL independence (10 of 11 studies, 3,228 participants), and evidence of longitudinal associations with mobility (3 of 3 studies, 883 participants) and ADL independence (7 of 10 studies, 1,511 participants). There was no conclusive evidence for association with falls. CONCLUSIONS: HS was the most studied measure and was associated with mobility, balance and ADL outcomes. There was a paucity of studies, particularly with longitudinal follow-up, measuring muscle mass, volume or thickness using gold-standard approaches.