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.