Azithromycin confers no effect on bronchial wall thickness, increases lumen area, radius

In patients with severe persistent asthma, treatment with azithromycin helps increase the bronchial lumen radius and lumen area, as shown in a study. However, it appears to have no significant effect on wall thickness.

A total of 90 patients with severe persistent asthma were randomized to receive azithromycin (250 mg, twice a day, 3 days a week), prednisolone (5 mg, twice a day), or placebo for 8 months in addition to standard therapy.

The primary outcome was an improvement in right upper lobe apical segmental bronchus (RB1) wall thickness, which was measured using high resolution computed tomography. Secondary outcomes were cough severity, dyspnoea severity, asthma control test (ACT) score, asthma exacerbation rate, pulmonary function tests, and fractional exhaled nitric oxide (FENO).

Of the patients, only 78 completed 8 months of treatment with azithromycin (n=25), prednisolone (n=27), or placebo (n=26). The primary efficacy outcome was not met, with no marked changes seen in bronchial wall thickness percentage across the treatment groups.

However, patients in the azithromycin and prednisolone groups showed a significantly increased inner radius and lumen area (p<0.05 for both).

Additionally, those who received azithromycin achieved meaningful improvements in dyspnoea severity, ACT score, FENO, and spirometry measures (forced expiratory volume in 1 second [FEV1], forced expiratory flow 25–75 percent, and FEV1/forced vital capacity; p<0.05 for all).

Cough severity or asthma exacerbation rate remained relatively the same even after 8 months of treatment with azithromycin.