Protein Supplements Increase Serum Insulin-Like Growth Factor-I Levels and Attenuate Proximal Femur Bone Loss in Patients with Recent Hip Fracture

doi:10.1059/0003-4819-128-10-199805150-00002

Protein Supplements Increase Serum Insulin-Like Growth Factor-I Levels and Attenuate Proximal Femur Bone Loss in Patients with Recent Hip Fracture

A Randomized, Double-Blind, Placebo-Controlled Trial

For author affiliations and current author addresses, see end of text. Grant Support: By grants from Sandoz Nutrition Ltd., Berne, Switzerland, and the Swiss National Research Science Foundation (grant no. 32-32415.91). Skin-test antigens for cellular hypersensitivity systems were supplied by Rhone-Poulenc, Thalwil, Switzerland. Acknowledgments: The authors thank M.N. Cerutti, RN, for devoted care of the patients; M. Jackson, RN, for help with patient recruitment; the staff of the osteodensitometry unit of Geneva University Hospital; G. Fourticq for muscle strength assessment; J.-L. Nussbaum for performing radiography; G. Rapatz (Institute for Medical Outcome Research) for statistical analysis; M. Perez for secretarial assistance; and E. White, MD, for reading the manuscript. They also thank J.-M. Dayer, MD; C.-H. Rapin, MD; J.-P. Michel, MD; H. Vasey, MD; P.D. Delmas, MD, PhD; and H. Schneider, PhD, for helpful discussion and support. Requests for Reprints: Rene Rizzoli, MD, Division of Bone Diseases, Department of Internal Medicine, University Hospital, CH-1211 Geneva 14, Switzerland; e-mail rizzoli@cmu.unige.ch. Current Author Addresses: Drs. Schurch, Rizzoli, and Bonjour: Division of Bone Diseases, World Health Organization Collaborating Center for Osteoporosis and Bone Disease, Department of Internal Medicine, University Hospital, CH-1211 Geneva 14, Switzerland.

Abstract

Background: Elderly persons who have osteoporotic hip fracture are often undernourished, particularly with respect to protein. Protein malnutrition may contribute to the occurrence and outcome of hip fracture.

Objective: To investigate whether oral protein supplements benefit bone metabolism in patients with recent hip fracture.

Design: 6-month, randomized, double-blind, placebo-controlled trial with a 6-month post-treatment follow-up.

Setting: University orthopedic ward.

Patients: 82 patients (mean age, 80.7 ± 7.4 years) with recent osteoporotic hip fracture. Patients received calcium supplementation, 550 mg/d, and one dose of vitamin D, 200 000 IU (at baseline).

Intervention: Protein supplementation, 20 g/d, or isocaloric placebo (among controls).

Measurements: Bone mineral density, biochemical markers of bone remodeling, calciotropic hormone levels, biochemically evaluated nutritional and immunologic status, and muscle strength were measured every 6 months.

Results: Compared with controls, patients who received protein supplements had significantly greater increases in serum levels of insulin-like growth factor-I (85.6% ± 14.8% and 34.1% ± 7.2% at 6 months; difference, 51.5 percentage points [95% CI, 18.6 to 84.4 percentage points]; P = 0.003) and an attenuation of the decrease in proximal femur bone mineral density ( −2.29%± 0.75% and −4.71%± 0.77% at 12 months; difference, 2.42 percentage points [CI, 0.26 to 4.59 percentage points]; P = 0.029). Seven and 13 new vertebral deformities were found among patients who received protein supplements and controls, respectively (P > 0.2). Median stay in rehabilitation wards was shorter for patients who received protein supplements than for controls (33 days [CI, 29 to 56 days] and 54 days [CI, 44 to 62 days]; difference, 21 days [CI, 4 to 25 days]; P = 0.018).

Conclusion: Protein repletion after hip fracture was associated with increased serum levels of insulin-like growth factor-I, attenuation of proximal femur bone loss, and shorter stay in rehabilitation hospitals.