Clinical study
Effect of short-term treatment with inhaled corticosteroid on airway wall thickening in asthma

https://doi.org/10.1016/j.amjmed.2003.11.026Get rights and content

Abstract

Purpose

Computed tomography studies demonstrate thickening of the asthmatic airway wall and its relation to disease severity. We evaluated the effect of inhaled corticosteroid on this phenomenon.

Methods

Cross-sectional images of the right upper lobe apical segmental bronchus were obtained by helical computed tomography in 45 corticosteroid-naïve patients with persistent asthma and 28 healthy controls. Airway wall thickness was measured as airway wall area normalized to body surface area. Computed tomography, pulmonary function, and serum levels of eosinophil cationic protein were examined before and after treatment with beclomethasone (800 μg/d for 12 weeks).

Results

Before treatment, airway wall thickness was greater in asthma patients than in controls (P <0.0001). After treatment, it decreased by 11% (P <0.001) but remained high (P <0.0001 vs. control); the serum level of eosinophil cationic protein decreased, and airflow obstruction was reduced, but not to the level in controls. The decrease in wall thickness was associated with a decrease in the serum level of eosinophil cationic protein (r = 0.39, P = 0.009) and an increase in the forced expiratory volume in 1 second (r = 0.45, P = 0.003) and was inversely related to disease duration at entry (r = –0.38, P = 0.009). Post-treatment wall thickness was related to disease duration (r = 0.45, P = 0.003) and remaining airflow obstruction.

Conclusion

Wall thickening of asthmatic central airways responds partially to inhaled corticosteroid therapy and may reflect an overall reduction in airway inflammation. “Unresponsive components,” possibly involving structural changes, may increase in the absence of inhaled corticosteroid treatment, potentially leading to chronic airflow obstruction.

Section snippets

Subjects

Fifty-one patients with persistent asthma and 28 healthy controls were recruited. All patients fulfilled the American Thoracic Society criteria for asthma (24), and none had ever received systemic or inhaled corticosteroids, cromones, or antileukotriene agents or had acute exacerbations of asthma during the previous 8 weeks. The severity of asthma was classified according to an international guideline (23). None of the subjects had ever smoked cigarettes, and none had a respiratory tract

Results

Six of the 51 enrolled patients were excluded: 2 had exacerbations of asthma requiring medication, 2 had respiratory tract infections at follow-up examinations, 1 refused repeated CT scanning, and 1 was lost to follow-up. In the 45 patients who completed the study, the mean duration of asthma was 7.3 ± 10.5 years (median, 3.4 years; interquartile range, 1.0 to 10.0 years). The asthma was mild in 9 patients, moderate in 25, and severe in 11.

There were no differences in age, sex, or body surface

Discussion

This study shows that treatment with moderate doses of inhaled corticosteroid for 12 weeks reduced airway wall thickness, as assessed by CT scans, modestly but significantly in patients with persistent asthma. However, airway wall thickness remained significantly greater than in controls.

The components of airway wall thickening that responded to treatment may have included inflammatory factors, since the decrease in wall thickness/body surface area correlated with a decrease in serum eosinophil

Acknowledgements

We thank Ryuzo Tanaka, Hiroyuki Akazawa, Noboru Narai, and Miho Morimoto for radiological and technical support, and Mafumi Kurozumi for handling the serum for measurement of eosinophil cationic protein.

References (41)

  • P.D Pare et al.

    The functional consequences of airway remodelling in asthma

    Monaldi Arch Chest Dis

    (1997)
  • F Paganin et al.

    Chest radiography and high resolution computed tomography of the lung in asthma

    Am Rev Respir Dis

    (1992)
  • L.-P Boulet et al.

    Airway responsiveness and bronchial-wall thickness in asthma with or without fixed airflow obstruction

    Am J Respir Crit Care Med

    (1995)
  • M Okazawa et al.

    Human airway narrowing measured using high resolution computed tomography

    Am J Respir Crit Care Med

    (1996)
  • G.G King et al.

    Evaluation of airways in obstructive pulmonary disease using high-resolution computed tomography

    Am J Respir Crit Care Med

    (1999)
  • R.H Brown et al.

    High-resolution computed tomography evaluation of airway distensibility and the effect of lung inflation on airway caliber in healthy subjects and individuals with asthma

    Am J Respir Crit Care Med

    (2001)
  • N Awadh et al.

    Airway wall thickness in patients with near fatal asthma and control groups: assessment with high resolution computed tomographic scanning

    Thorax

    (1998)
  • K Kasahara et al.

    Correlation between the bronchial subepithelial layer and whole airway wall thickness in patients with asthma

    Thorax

    (2002)
  • S.A Little et al.

    High resolution computed tomographic assessment of airway wall thickness in chronic asthma: reproducibility and relationship with lung function and severity

    Thorax

    (2002)
  • Y Nakano et al.

    Quantitative assessment of airway remodeling using high-resolution CT

    Chest

    (2002)
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