Bronchiectases at Early Chest Computed Tomography in Children with Cystic Fibrosis Are Associated with Increased Risk of Subsequent Pulmonary Exacerbations and Chronic Pseudomonas Infection

Background: Children with cystic fibrosis (CF) are often Pseudomonas aeruginosa (PsA) free and exhibit normal spirometry between the ages of 5 and 7. It is reported that computed tomography (CT) is more sensitive than FEV1 as an instrument in the identification of pulmonary disease. It is not known whether CF-CT scores in childhood may be used to highlight children at risk of developing severe disease.

Aims: 1 - To assess the number of respiratory exacerbations (RTEs) during a follow-up period of 6 years and their correlation with the CF-CT scores in young CF children. 2 - To assess whether PsA-negative CF children with high chest CF-CT scores are more likely to develop chronic PsA lung infection.

Methods: 68 chest CT performed in patients without chronic PsA infection were scored. All patients (median age 7.8 years) had at least 4 clinical, functional and microbiologic assessments/year in the subsequent 6 years. RTE was defined as hospitalization and IV antibiotic treatment for respiratory symptoms.

Results: 86.8% patients had <3 RTEs in the 6 year follow-up period. The number of RTEs in the 6 years subsequent to the CT scan was correlated to the bronchiectasis CT score (BCTS) (r = 0.612; p < 0.001) and to FEV1 at baseline (r = -0.495, p<0.001). A BCTS ≥ 17.5 identified patients with >3 RTEs during follow-up (sensitivity: 100%, specificity: 85%), while FEV1 did not. Only BCTS was significant in a logistic multivariate model (RR 1.15). BCTS was significantly lower and FEV1 higher in patients who did not develop chronic PsA infection by the end of the study.

Conclusion: In CF children free from chronic PsA, both CT scores and FEV1 values demonstrate significant correlation with disease severity in the subsequent 6 years but CT score has higher predictive value in the identification of patients at risk.