Research in context
Evidence before this study
Asthma is a common chronic inflammatory airway disease worldwide. Severe exacerbations and poor control persist in people treated with maintenance asthma therapy, showing a need for additional therapeutic options. Macrolide antibiotics have anti-inflammatory, antibacterial, and antiviral effects that might be beneficial in asthma. We searched PubMed on Dec 12, 2016, for randomised controlled clinical trials of macrolides for asthma in adults that were published in English, using the search terms “asthma AND (macrolide OR azithromycin) AND clinical trial AND adult”. The search was done from Jan 1, 1980 onwards and identified randomised controlled trials and systematic reviews of clinical trials. These studies identified a potential benefit of macrolides on asthma symptoms, but gave inconsistent results for an effect on asthma exacerbations and for phenotype-specific effects. Systematic reviews were unable to draw conclusions about the effects on other endpoints, including exacerbations, due to lack of data, heterogeneity of results, and inadequate study design.
Added value of this study
Our study provides clear evidence of benefit of add-on azithromycin in reducing asthma exacerbations in adults with uncontrolled asthma who are taking maintenance inhaled corticosteroid and a long-acting bronchodilator. We also show improved quality of life with azithromycin treatment of persistent asthma. Additionally, we identify a beneficial effect of azithromycin in reducing episodes of respiratory infection. The treatment was well tolerated.
Implications of all the available evidence
Using azithromycin in addition to inhaled corticosteroids and long-acting bronchodilators could substantially improve the health of people with uncontrolled persistent asthma.