Tracking CF disease progression with CT and respiratory symptoms in a cohort of children aged 6-19 years

Introduction: Cystic fibrosis (CF) lung disease is characterized by bronchiectasis and trapped air on chest computed tomography (CT). Objective: We aim to validate bronchiectasis and trapped air as outcome measures by evaluating associations between changes in bronchiectasis, trapped air and patient-reported respiratory symptoms. Methods: A longitudinal cohort study has been conducted. CF patients (aged 6-19 years) who had two routine CTs and completed twice a Cystic Fibrosis Questionnaire-Revised within 2 years (referred to as T₁ and T₂), in the period of July 2007 to January 2012 were included. Bronchiectasis and trapped air were scored using the CF-CTscoring system. Correlation coefficients and student's paired ttests were performed. Results: In total 40 patients were included with a median age at T₁ of 12.6 years (range 6-17 years), and at T₂ 14.5 years (range 8-19 years). At T₁, bronchiectasis (r= -0.49, P< 0.01) and trapped air (r = -0.34, P=0.04) correlated with CFQ-R Respiratory Symptoms Scores (CFQ-R RSS). At T₂ similar correlations were found with the CFQ-R RSS. Over 2 years, there was significant progression in bronchiectasis (P=0.03) and trapped air (P=0.03), but not in CFQ-R RSS. Changes in bronchiectasis and trapped air were not associated with changes in CFQ-R RSS. Conclusion: Our results indicate that bronchiectasis and trapped are sensitive outcome measures in CF lung disease, showing a significant association with CFQ-R RSS at two-time points. However, progression of bronchiectasis and trapped air over 2 year does not necessarily correlate to changes in quality of life.