Metformin Improves Sarcopenia-Related Quality of Life in Geriatric Adults: A Randomized Controlled Trial

Metformin protects against age-related muscle decline, termed sarcopenia. However, the effects on sarcopenia quality-of-life (SarQoL) are unknown. We investigated the effects of metformin on SarQoL and associated mechanisms in older adults. This double-blind randomized, placebo-controlled trial included geriatric adult men, divided into non-sarcopenic controls (age = 72.2 ± 4.3 years, n = 52) and two groups of patients with sarcopenia randomized into placebo (age at baseline = 74.4 ± 5.7 years, n = 54) and metformin (age at baseline = 71.2 ± 3.9 years, n = 47) groups. Patients in the metformin group received 1.7 grams twice daily for four months. We evaluated SarQoL, handgrip strength (HGS), plasma zonulin, c-reactive protein (CRP), and 8-isoprostanes. Patients with sarcopenia had lower HGS and SarQoL than controls (both p <0.05). Metformin improved the HGS and the SarQoL domains related to physical and mental health, locomotion, and leisure activities, as well as cumulative SarQoL scores (all p <0.05). Metformin also prevented the decline in the SarQoL domains for functionality and fear. Among plasma biomarkers, metformin reduced the levels of zonulin, CRP, 8-isoprostanes, and creatine kinase. We also found a significant correlation of plasma zonulin with cumulative SarQoL in patients with sarcopenia taking metformin, suggesting a role for intestinal repair in improving SarQoL. Finally, metformin did not affect body composition and gait speed. Overall, metformin improved HGS and SarQoL by repairing intestinal leakage. Our data have clinical relevance for improving the quality of life in older adults with sarcopenia.