Serum Levels of Insulin-Like Growth Factor-I Are Positively Associated with Functional Outcome After Hip Fracture in Elderly Women

Abstract

To investigate the association between serum levels of insulin-like growth factor-I (IGF-I) and functional outcome in hip-fracture women. We investigated 171 of 188 women admitted consecutively to a rehabilitation hospital after hip fracture. IGF-I serum levels were assessed by using an automated chemiluminescence immunoassay 21.3 +/- 6.1 days (mean +/- SD) after fracture occurrence. Functional outcome was assessed using Barthel index scores. At a Spearman rank test we observed a significant positive correlation between IGF-I levels and both Barthel index scores at discharge from inpatient rehabilitation (rho = 0.213; P = 0.005) and changes in Barthel index scores during rehabilitation (rho = 0.222; P = 0.004). At multiple regression, a significant association between IGF-I and both functional scores and their changes during rehabilitation was found after adjustment for several potential confounders, including age, cognitive impairment, pressure ulcers, neurologic impairment, infections, Barthel index score at admission to rehabilitation, and length of stay in hospital (P < 0.05). Overall, the panel of prognostic factors accounted for 55% of the variance in the functional score and 31% of the variance in its change during rehabilitation. IGF-I serum levels were significantly associated with ability to function after hip fracture in women.