Hyperprotein Nutritional Intervention in Elderly Patients With Hip Fracture and Sarcopenia

Overview

1. RATIONALE The unique characteristic of our study lies in the attempt to reverse the functional impairment experienced by sarcopenic patients with hip fracture using nutritional intervention. What makes this study different from prior studies is that it will be conducted in a hospital setting, unlike most prior studies, which were conducted in a community setting. The association between muscle mass and strength, inflammatory indices, and functional impairment versus dependence and fragility will also be measured. 2. HYPOTHESIS The hypothesis of our study is that nutritional intervention enriched in metabolites of essential amino acids (beta-hydroxy-beta-methylbutyrate) is effective for treating sarcopenia in elderly patients with hip fracture and improves functional level. 3. OBJECTIVES Primary objective is to assess functional improvement after nutritional intervention in sarcopenic patients with hip fracture, as measured using Barthel index. Secondary objectives will include: 1) to show the relationship between metabolic and inflammatory indices and sarcopenia; 2) to show how sarcopenia and its treatment influence the risk of fall; 3) to show muscle mass improvement; 4) to show increased strength; 5) to assess mortality and morbidity. 4. EXPECTED RESULTS The investigators expect to find that the supplemented group experiences throughout the study period a significant improvement in functional status (Barthel index), an increase in muscle mass, and a reduction in fat mass. An increased strength and a reduction in associated complications (falls) are also expected. The investigators hope to be able to show reductions in inflammatory indices and insulin resistance. To conclude, by improving muscle strength and mass the investigators expect to find a reduction in the disability and dependence of this population group.

INTRODUCTION Sarcopenia is the loss of muscle mass and function associated to age. Rosemberg first spoke of sarcopenia in 1989. A progressive loss of muscle mass occurs from approximately 40 years of age. This loss is estimated at about 8% by decade until the age of 70 years, after which the loss increases to 15% by decade. Healthcare costs attributable to sarcopenia in the United States (US) in 2000 were estimated to be 18.5 billion dollars. It would be natural to assume a direct relationship between muscle mass and strength, but loss of muscle mass is not the main mechanism for loss of strength. Proximal femur (hip) fracture is a substantial cause of morbidity and mortality in the elderly. One-year mortality after a hip fracture ranges from 12% and 37%, with an 11% incidence during the first few months. Twenty-five percent of elderly patients with hip fracture require institutionalization, at least temporary, and only 40% fully recover their pre-fracture functional status. Nutritional therapy, particularly beta-hydroxy-beta-methylbutyrate (HMB), a metabolite of the essential amino acid, leucine, has aroused great expectations. All prior studies about nutritional supplementation with HMB have shown an improved muscle metabolism, decreased protein degradation, and a significant increase in fat-free mass in both young and elderly people.