Long-term changes in airway-wall thickness on computed tomography in asthmatic patients

Effects of long-term treatment with inhaled corticosteroids (ICSs) on airway-wall thickness in patients with asthma remain unknown.

To determine whether airway-wall thickness consistently decreases after long-term ICS treatment, and to analyze factors contributing to long-term airway-wall changes in asthmatics.

A retrospective analysis of long-term changes in airway-wall thickness using computed tomography was performed in 14 patients with asthma. Wall area corrected by body surface area (WA/BSA) was examined at baseline, 12 weeks after the commencement of ICSs (second measurement), and at least 2 years (mean +/- SEM. 4.2 +/- 0.5) after the second measurement (third measurement). Mean +/- SEM changes in WA/BSA from the second to the third measurements were analyzed.

The mean change in WA/BSA was not significant between the second and the third measurements (-0.27 +/- 0.59 mm2/m2/y). Overall, the changes were significantly associated with disease duration but not with other clinical indices. When the 14 patients were divided into 2 groups using a cutoff value of 0.32 mm2/m2/y for the mean change in WA/BSA, for the 5 patients whose WA/BSA exceeded this cutoff, daily ICS doses were not reduced and both forced expiratory volume in the first second (FEV1) and forced vital capacity decreased significantly. For the remaining 9 patients, daily ICS doses were reduced and long-term FEV1 values did not change.

Despite long-term treatment with ICSs, airway-wall thickness did not consistently decrease. One possible mechanism underlying poor response to long-term treatment may be long-standing asthma.