Rationale Conducting clinical trials in cystic fibrosis (CF) preschoolers has been limited by lack of sensitive lung function measures performed across sites. Objectives (1) Assess feasibility and short-term reproducibility of spirometry, forced oscillometry (FO), and inductance plethysmography (IP) in a multi-center preschool population; (2) compare ability of each technique to differentiate lung function of CF preschoolers and controls; (3) evaluate longitudinal changes in lung function; (4) estimate sample sizes for future trials. Methods A longitudinal, multi-center study of CF preschoolers was conducted utilizing standardized equipment, rigorous site training, and centralized lung function data review. CF subjects participated in up to four study visits 6 months apart, plus a 2-week reproducibility visit. Controls had one study visit. Results Ninety-three CF subjects and 87 controls participated. Acceptability rates were lowest for spirometry (55%) and highest for IP (77%). Spirometry success increased with age and having a prior acceptable measurement. FEV 1, FEV 0.5, and FEF 25-75 were lower for CF subjects than for controls; spirometric z-scores declined with age. IP measures of thoracoabdominal asynchrony were greater for CF subjects than for controls. FO indices did not distinguish CF from controls. FEV 1 and FEV 0.5 are able to detect the smallest treatment effect for a given sample size. Conclusions Spirometry appears more sensitive than IP or FO for detecting lung disease in CF preschoolers; spirometric indices decline with age. Future trials using spirometry should include a run-in period for training and require acceptable data prior to enrollment. However, near-normal spirometric measurements in CF preschoolers may lead to difficulty detecting a treatment effect.
- forced expired volume (mesh terms)
- forced oscillometry
- inductance plethysmography
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health
- Pulmonary and Respiratory Medicine