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Metformin added to lifestyle intervention for physical function in older adults with obesity (DEMFOS trial): a randomised controlled trial

Nava MLD, Viola V, Aguilar M, Bryant MS, Nambi V, Armamento-Villareal R, Qualls C, Villareal DT

The lancet. Healthy longevity, 2026

221 participants · 1 citation

Abstract

Background: Obesity in older adults is associated with functional decline and increased risk of disability. Lifestyle interventions improve physical function, but the role of metformin as an adjunct to lifestyle intervention in this population remains unclear. In this randomised clinical trial, we evaluated whether metformin enhances the effects of an intensive lifestyle intervention on physical function in older adults with obesity.

Methods: The Diet and Exercise plus Metformin to Treat Frailty in Obese Seniors (DEMFOS) trial (ClinicalTrials.gov: NCT04221750 [completed]) was a randomised, placebo-controlled trial conducted at the Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine (Houston, TX, USA). Older adults (aged 65-85 years) with obesity (BMI ≥30 kg/m2) were randomly assigned to intensive lifestyle intervention (weight-management and exercise training) plus placebo, intensive lifestyle intervention plus metformin, or healthy lifestyle (diet education) plus metformin groups. The primary outcome was change in the modified physical performance test score at 6 months. The primary analysis was by intention-to-treat.

Findings: Of 221 participants assessed for eligibility between March 30, 2021, and Dec 12, 2024, 114 were included in this study (mean age 72·8 years [SD 5·2]; 101 [89%] men and 13 [11%] women). 64 (56%) participants were White, 50 (44%) were Black, and 15 (13%) were Hispanic or Latino. Changes in physical performance test differed…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 221 participants or records.

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