Endocrine Abstracts

Introduction: Ageing is associated with a decrease in activity of the growth hormone / IGF-1 axis. However, there is little normative data for serum IGF-I levels in the very elderly and the relationship of IGF-1 levels to muscle function and physical performance in geriatric inpatients has not been fully explored. We studied elderly patients rehabilitating after proximal femoral fracture (PFF), hypothesising that patients with lower circulating IGF-1 levels would have poorer physical outcomes.

Methods: Thirteen PFF patients admitted to a geriatric orthopaedic rehabilitation unit were studied at baseline, and after 6 weeks rehabilitation. Measurements included serum IGF-1 levels, leg extensor power (LEP, watts/kg, using the Nottingham Power Rig), Barthel index (BI) score and the elderly mobility scale.

Results: The median age was 79 yrs (range 70-94). The median IGF-1 level at baseline was 120ng/ml (range 76-167 ng/ml) and at 6 weeks 108.5ng/ml, p=0.644. There was a significant inverse relation between age and serum IGF-I levels (r=-0.58; p<0.03). There was no significant correlation between baseline IGF-1 levels and baseline LEP. However, baseline IGF-1 levels correlated with 6-week LEP in both the fractured and non-fractured legs [Pearson correlations 0.619 (p<0.05) and 0.581 (p<0.05) respectively]. IGF-1 levels at 6 weeks had stronger correlations with 6-week LEP in both the fractured and non-fractured legs [Pearson correlations 0.786 (p=0.002) and 0.817 (p=0.001) respectively]. IGF-1 levels at 6 weeks also correlated with 6-week BI (Pearson correlation 0.615, p<0.05).

Conclusions: IGF-1 levels after PFF correlate well with outcome LEP and with some measures of physical performance. Studies of interventions that raise concentrations of IGF-1 are required to determine whether they improve outcome in this group of patients.