A six-month study of growth and energy expenditure in children with cystic fibrosis taking a pulmonary inhalation medication (rhDNase)

Objective: To characterize the effects of recombinant human deoxyribonuclease (rhDNase) on growth velocity, body composition, resting energy expenditure (REE) and food intake in children with cystic fibrosis (CF). Methods: A prospective, six-month pilot study was conducted in twenty-one subjects with CF (twelve male, nine female, ages 11.5+/-3.1 years) measured at baseline, two and six months post-baseline. Repeated measures ANOVA was used to examine the change in variables across time. Results: The majority (75%) of subjects had minimal lung disease at baseline (FEV1: 80%-119% predicted). As expected for growing children, weight and height gains (1.6 kg and 2.5 cm) were observed between baseline and six months (p=0.0001). No change was observed in weight z-scores from six months prior to initiation of rhDNase therapy to six months post, though a significant decline (p=0.049) in Ht z-score was observed over this twelve-month period. Triceps skinfolds and mid-arm muscle circumference increased from baseline to six months (p<0.01); respective z-scores remained stable. Energy intake remained constant during the period it was studied from baseline to two months of therapy: 120%+/-27% RDA. REE, though slightly elevated compared to healthy children (baseline 106%+/-8% predicted), remained stable throughout the study and at a level which may be expected for children with minimal lung disease. A trend (p=0.057) towards a decrease in the number of subjects requiring hospitalization for pulmonary exacerbations during the trial period was observed. Conclusions: In summary, these pilot data from younger children with milder CF-related lung disease do not confirm anecdotal reports of improved rate of weight gain, caloric intake or decreases in the elevated REE. Future research might focus on documentation of the possible nutritional effects of rhDNase in clinical trials of children with more severe lung disease.