Background and objectives: Functional deterioration and reduced mobility in elderly patients with a hip fracture are associated with a loss of both muscle mass and function (sarcopenia). The aim of this study was to assess whether oral nutritional supplementation (ONS) improves muscle mass and nutritional markers (BMI, proteins) in elderly patients with hip fracture.
Methods: Patients aged 65 years and over with hip fractures admitted to either of two rehabilitation facilities were included. Patients with diabetes, with Barthel index scores <40 prior to the fracture or with pathological fractures were excluded. A random-numbers generator was used to randomly allocate patients to the intervention group (IG) or the control group (CG). Those in the IG received a standard diet plus ONS in the form of two bottles a day of β-hydroxy-β-methylbutyrate (HMB), while those in the CG received a standard diet only. The intervention was not blinded. In order to assess changes in body mass index (BMI), anthropometric parameters were recorded at both admission and discharge. Patients' functional situation was evaluated using the Barthel index (BI) and the Functional Ambulation Categories (FAC) score. Muscle mass was assessed using bioelectrical impedance analysis, which allowed us to calculate appendicular lean mass (aLM). The outcome variable was the difference between aLM upon discharge, minus aLM upon admission (Δ-aLM).
Results: Of the 107 randomised patients (IG n55, CG n52), 49 finished the study in the IG and 43 in the CG. BMI and aLM were stable in IG patients, whilst these parametres decreased in the CG. A significant difference was observed between the two groups (p<0.001, and p=0.020 respectively). The predictive factors for Δ-aLM were ONS (p=0.006), FAC prior to fracture (p<0.001) and BI prior to fracture (p=0.007). The concentration of proteins (p=0.007) and vitamin D (p.001) had increased more in the IG than in the CG.
Conclusion: A diet enriched in HMB improves muscle mass, prevents the onset of sarcopenia and is associated with functional improvement in elderly patients with hip fractures. Orally administered nutritional supplements can help to prevent the onset of sarcopenic obesity.
Trial registration: www.clinicaltrials.gov identifier: NCT01404195, registered 22 July 2011, HYPERPROT-GER Study.
Keywords: Hip fracture; Muscle mass; Oral nutritional supplementation; Sarcopenia; β-Hydroxy-β-methylbutyrate (HMB).
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