Study Design
This study utilized a combination of retrospectively and prospectively
collected data. The retrospective data were acquired from 23 infants who
had iPFTs performed at Riley Hospital for Children from 2012-2018 as
part of clinical care and 12 infants who underwent iPFTs as part of
other research studies
(ClinicalTrials.gov NCT01973192 and
NCT04026360). We prospectively recruited an additional 10 infants
followed at the CF Center at Riley Hospital for lung function testing,
bringing the total sample size to 45 infants.
The inclusion criteria were (1) an age at time of iPFTs of 12-24 months
of age and (2) a diagnosis of CF through NBS 22.
Exclusion criteria included gestational age less than 36 weeks. The
study was approved by the Indiana University Institutional Review Board
and informed written consent was obtained from the parents of
prospectively recruited infants.
Clinical data, including mutation analysis, ethnicity, respiratory
cultures, antibiotic and systemic steroid courses, smoke exposure,
history of wheezing and nutritional indices, were obtained from the
electronic medical record. Nutritional status indices obtained for this
study were weight-for-age (WFA) and weight-for-length (WFL) z-scores
based on the Centers for Disease Control growth charts during the first
24 months of life 23. Weight and crown-heel lengths
were obtained during CF clinic visits and during iPFT testing.