Longitudinal pulmonary function of childhood bronchiectasis and comparison with cystic fibrosis

Little has been published on the progression of non-cystic fibrosis bronchiectasis (BX), especially in childhood. Data are needed for prognosis and evaluation of the effectiveness of treatments. A study was undertaken to evaluate the change in lung function over time in children with BX, and to consider covariates and compare them with the local cystic fibrosis (CF) population.

Children with BX or CF and > or =3 calendar years of lung function data were identified from hospital clinics. Diagnosis was made by high resolution CT scans, sweat tests, and genetic studies. Lung function performed on a single plethysmograph between 6 and 15 years of age and > or =6 weeks after diagnosis was analysed longitudinally (linear mixed model). The impact of reference equation and "best annual" versus "all data" approaches were evaluated.

There were 44 children in each of the BX and CF groups with an overall mean 5.7 calendar years follow up data. The estimated forced expiratory volume in 1 second (FEV(1)) in the BX group had an intercept of 68% predicted (Polgar) at 10 years of age which fell at a rate of 1.9% per annum using "best annual" data compared with 63% and 0.9% using "all data". Those with post-infectious BX or chronic Haemophilus influenzae infection had more severe disease. In CF the FEV(1) ("best annual") intercept was 85% predicted with a slope of -2.9% per annum. The choice of reference equation affected the magnitude of the result but not the conclusions.

Children with BX have significant airway obstruction which deteriorates over time, regardless of analysis strategy or reference. Effective interventions are needed to prevent significant morbidity and adult mortality.