Longitudinal analysis of resting energy expenditure in patients with cystic fibrosis.

Objective To assess whether elevated resting energy expenditure (REE) in female patients with cystic fibrosis (CF) persists longitudinally during late childhood and puberty. Study design REE and body composition were measured 3 times in 2 years in 86 children with CF. Pubertal status, bacterial colonization, liver disease, pancreatic and pulmonary function, and genotype were determined, and linear mixed model analyses were used to determine predictors and changes in REE longitudinally. Results REE did not change with time allowing for fat free mass, pancreatic insufficiency (PI), or severe mutations. Pulmonary function and liver disease were not significant predictors of REE. Percentage predicted REE compared with control data was higher (P = .002) in female patients with CF (109.5%) and lower in male patients with CF (104%) and persisted with time. In post-menarchal female patients with CF, REE adjusted for fat free mass was 366 kJ/d lower than in pre-menarchal female patients, but still 112% predicted. Conclusions This longitudinal study demonstrates that REE is elevated in patients with CF with PI and severe mutations. The elevation of percentage predicted REE was greater in female patients than male patients and persisted for 2 years, and during pubertal maturation, independent of pulmonary and liver disease. These results highlight the need for a high-energy diet throughout childhood and adolescence, particularly in female patients with PI.