Serum levels of insulin-like growth factor-1 in the three months following surgery for a hip fracture in elderly: relationship with nutritional status and inflammatory reaction

Background and aims: Serum IGF-1 level declines with advancing age and is a reliable index of protein-energy undernutrition in elderly patients in a metabolically stable condition. We have examined the value of IGF-1 as an indicator of malnutrition in elderly patients during recovery within 1 month after surgery for a hip fracture and we have studied the relationship between changes in IGF-1 levels, nutritional status and inflammatory reaction during 2 month follow up.

Study design: Forty elderly patients (mean age 84.0+/-1.9) were nutritionally assessed upon admission to our rehabilitation unit (D0) then monthly (D30-D60) by measurement of anthropometric and biological parameters. Two groups of patients were defined on the basis of mid-arm circumference (MAC) and tricipital skinfold thickness (TST) measurement at D0: group 1, undernourished (n=13) and group 2, normally nourished (n=27). Changes in anthropometric and biological parameters during the study were compared between these two groups of patients.

Results: IGF-1 level was significantly lower in group 1 (79.5+/-9.1 vs 108+/-8.6 ng/ml, P<0.05) while usual serum protein levels were in the same range in the two groups. Orosomucoid level significantly decreased during 2 month follow-up in group 2 (P<0.01), CRP level decreased but not significantly. TST and MAC decreased in group 2 (respectively P<0.02 and P<0.05) while anthropometric parameters tended to slightly increase in group 1 in relation with an increase in caloric intake (P<0.05). IGF-1 level increased significantly during the study in group 2 (P<0.05) and was significantly lower in patients with complications occurring between D0 and D30 in comparison with patients without complications (respectively P<0.05 at D0, P<0.02 at D30). IGF-1 level correlated with body mass index, MAC, TST, muscle midarm circumference, albumin and transthyretin levels. Changes in IGF-1 levels positively correlated with those in transthyretin levels and negatively with those in orosomucoid levels.

Conclusion: IGF-1 level seems a reliable index of protein-energy under-nutrition in elderly patients in the recovery period after surgery for a hip fracture. This marker is influenced by the inflammatory reaction. Decline of inflammatory reaction, rather than change in nutritional status, is responsible for the variation in IGF-1 level during a 2 month follow-up.