Prospective longitudinal association between repeated multiple breath washout measurements and computed tomography scores in children with cystic fibrosis

• Published in: Journal of cystic fibrosis Vol. 20; no. 4; pp. 632 - 640
• Main Authors: Sandvik, Rikke Mulvad, Kongstad, Thomas, Green, Kent, Voldby, Christian, Buchvald, Frederik, Skov, Marianne, Pressler, Tacjana, Nielsen, Kim Gjerum
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-07-2021
• Subjects: Child; Child, Preschool; Cystic fibrosis; Cystic Fibrosis - complications; Cystic Fibrosis - diagnostic imaging; Cystic Fibrosis - physiopathology; Female; Humans; Infant; Longitudinal Studies; Lung clearance index; Lung Diseases - diagnostic imaging; Lung Diseases - etiology; Lung Diseases - physiopathology; Lung function; Male; Multiple breath washout; PRAGMA-CF; Progression; Prospective Studies; Respiratory Function Tests; Second moment ratio; Spirometry; Spirometry-controlled CT; Structural lung disease; Tomography, X-Ray Computed; Progression; Structural lung disease; Spirometry-controlled CT; Lung function; Multiple breath washout; Cystic fibrosis; Second moment ratio; Lung clearance index; PRAGMA-CF
• ISSN: 1569-1993; 1873-5010
• DOI: 10.1016/j.jcf.2020.09.010

•Progression in CF lung disease was assessed by spirometry-controlled CT using PRAGMA-CF as scoring system, nitrogen multiple breath washout (N2MBW) and spirometry.•Structural lung disease in children with CF was stable over 2 years.•The proportion of lung volume with bronchiectasis (%Bx) decreased in 50% of children.•Stable outcomes from N2MBW were associated with stable structural lung disease.
Progression of structural lung disease (SLD) is a major risk factor for morbidity in patients with cystic fibrosis (CF). We studied changes in SLD and correlations with spirometry and nitrogen multiple breath washout (N2MBW) outcomes to explore associations in contemporary evolution between structural and functional abnormalities in CF lung disease.
Spirometry-controlled chest-CTs using PRAGMA-CF for scoring extent of SLD, spirometry, and N2MBW were performed at two-year intervals in school-age children with CF.
Fifty-seven children aged 6–18 years were included. No significant progression in mean PRAGMA-CF scores was observed. Half of the children showed improvement in the proportion of bronchiectasis (%Bx). Lung Clearance Index (LCI) and the second moment ratio (M2) increased significantly and baseline values correlated significantly with SLD at follow-up (p ≤ 0.0002). The correlation between the change in M2 (∆M2) and the change in total SLD was R = 0.27 (p = 0.048). We found high negative predictive values (100%) for ∆M2<10% to exclude progression in SLD. For stable or improving values of LCI and M2, the predicted probability for progression in SLD was 16% and 14%, respectively (upper 95% confidence limit: 33%). Evolution in N2MBW and CT outcomes was discordant in half of the children.
We found no progression in SLD over 2 years in school-age children with CF, in contrast to both LCI and M2, which along with discordant outcomes in half of the children underlines that N2MBW and CT assess different aspects of CF lung disease. However, stable outcomes from N2MBW were associated with stable structural lung disease.