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.

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.