Background
The optimal strategy for monitoring cystic fibrosis (CF) lung disease in infancy remains unclear.
Objective
To describe longitudinal associations between infant pulmonary function tests (iPFTs), chest radiograph (CXR) scores and other characteristics.
Methods
CF patients †24 months old were enrolled in a 10-center study evaluating iPFTs 4 times over a year. CXRs ~1 year apart were scored with the Wisconsin and Brasfield systems. Associations of iPFT parameters with clinical characteristics were evaluated with mixed effects models.
Results
The 100 participants contributed 246 acceptable flow/volume (FEV0.5, FEF75) and 303 acceptable functional residual capacity (FRC) measurements and 171 CXRs. Both Brasfield and Wisconsin CXR scores worsened significantly over the 1 year interval. Worse Wisconsin CXR scores and S. aureus were both associated with hyperinflation (significantly increased FRC) but not with diminished FEV0.5 or FEF75. Parent-reported cough was associated with significantly diminished FEF75 but not with hyperinflation.
Conclusions
In this infant cohort in whom we previously reported worsening in average lung function, CXR scores also worsened over a year. The significant associations detected between both Wisconsin CXR score and S. aureus and hyperinflation, as well as between cough and diminished flows, reinforce the ability of iPFTs and CXRs to detect early CF lung disease.