Anabolic effects of growth hormone treatment in young children with cystic fibrosis

Abstract

Background: Malnutrition is commonly found in children with Cystic Fibrosis (CF) and is characterized by poor weight gain and linear growth. Almost one-third of children with CF are below 5th percentile for weight and height. Intensive nutritional supplementation may not result in sustained improvement in weight gain and linear growth.

Objective: To evaluate the anabolic effects of GH, Humatrope (Eli Lilly, 0.05 mg/kg/day) was administered to five children with CF (3 males/2 females) for an average period of 2 years.

Methods: All patients were maintained on caloric intake of 1.3-2.0 times the recommended daily allowance. Patients underwent standard growth hormone (GH) stimulation studies and measurement of IGF-1 and IGFBP-3.

Results: The mean +/- SE for age and skeletal age were 3.2 +/- 0.85 years and 2.0 +/- 0.45 years, respectively. Growth was assessed by determining both weight and height, which were normalized for age and sex by calculating Z scores using HANES I reference data. Differences in Z scores between clinic visits (delta Z) were calculated for both weight and height to determine changes in growth velocity. The mean Z scores for weight and height were markedly attenuated in CF children as compared with healthy children (-1.95 +/- 0.23 and -2.8 +/- 0.27, respectively). The mean +/- SE for maximum stimulated GH value, IGF-1 and IGFBP-3 were 9.2 +/- 1.2 ng/dl, 67 +/- 6 ng/ml, and 1.7 +/- 0.22 mg/L, respectively. GH treatment improved weight and height Z scores (-0.11 +/- 0.05 and -0.94 +/- 0.18, p < 0.01) significantly. The delta Z scores for weight and height were significantly increased during first and second year of GH treatment (p < 0.02). Also, the average values of IGF-1 and IGFBP-3 were significantly increased as compared to pretreatment values (186 +/- 37 ng/ml and 3.0 +/- 0.22 mg/L, p < 0.01).

Conclusions: GH treatment significantly improves weight and linear growth in young patients with CF. These data suggest that anabolic effects of GH may be beneficial for treatment of malnutrition in children with CF.