RESUMEN
BACKGROUND: Chronic undernutrition is a common condition in older people with low socioeconomic status and is clearly an important component of frailty. However, it is uncertain whether protein-energy supplementation can prevent functional decline in this group. METHODS: Eighty-seven frail older adults (usual gait speed, <0.6 m/second; Mini Nutritional Assessment, <24) were enrolled in this randomized controlled trial. Participants were randomly assigned to either an intervention group, which was provided two 200-mL cans of commercial liquid formula (additional 400 kcal of energy, 25g of protein, 9.4g of essential amino acids, 400mL of water) per day for 12 weeks, or the controls group, which did not receive this supplement. The primary outcomes were the change of the Physical Functioning and Short Physical Performance Battery. Usual gait speed, timed up-and-go test, hand grip strength, and one-legged stance were also measured as secondary outcome variables. RESULTS: Physical Functioning increased by 5.9% (1 point) in the intervention group, although no change was observed in the control group (p =.052). Short Physical Performance Battery remained stable in the intervention group, although it decreased by 12.5% (1 point) in controls (p = .039). Usual gait speed decreased by 1.0% in the intervention group versus 11.3% (0.04 m/second) in controls (p = .039). Timed up-and-go improved by 7.2% (1.1 seconds) in the intervention group and worsened by 3.4% (0.9 seconds) in controls (p = .038). There were no differences between groups in hand grip strength or one-legged stance performance. CONCLUSIONS: The results indicate that protein-energy supplementation administered to frail older adults with low socioeconomic status shows evidence of reducing the progression of functional decline.