The effect of maintenance azithromycin on radiological features in patients with bronchiectasis - Analysis from the BAT randomized controlled trial

Rationale: Bronchiectasis (abnormal dilatation of bronchi) is usually diagnosed by high resolution computed tomography (HRCT) and radiological severity has been found to correspond with clinical outcome. A beneficial effect of macrolides maintenance treatment in frequent exacerbating bronchiectasis patients has been established in randomized trials. This study was undertaken to prospectively evaluate the effect of long-term azithromycin (AZM) on radiological features in patients with bronchiectasis.

Methods: The BAT randomized controlled trial (2008-2010) investigated the effect of 1 year of AZM (250 mg OD) in bronchiectasis with frequent exacerbations. Chest (HR)CT-scans at baseline and after one year of study treatment were obtained and scored by two radiologists according to the Brody - and the Bhalla scoring system.

Results: 77 (93%) patients conducted the BAT trial were evaluated in this post-hoc analysis. A significant improvement of the radiological features based on the Brody score was found after one year of AZM therapy as compared to placebo (p = 0.024), with a not significant improvement of the Bhalla score (p=0.071). Especially the consolidation (Bhalla) and parenchymal changes (Brody) sub scores significantly improved (both p=0.030), and even a radiological deterioration was seen on the Brody bronchiectasis sub score for the placebo treated patients (mean 14.5 (11.7) vs.15.7 (11.9)).

Conclusions: The beneficial effect of long-term AZM treatment on radiological features was demonstrated in this randomized controlled trial. (HR)CT's can be used as an objective measure of treatment response in bronchiectasis.

Clinical trial registration number: NCT00415350.