Background: Asthma is a chronic disease of the airways in which inflammation of the respiratory mucosa plays a crucial role. The mechanisms responsible for the maintaining of this inflammatory response are only partially known and there is evidence that a role could be paid by chronic infection by intracellular pathogens (such as Chlamydia pneumoniae). Macrolides are antibiotics with both antimicrobic and antiinflammatory activities and thus their use in asthmatic patients could lead to reduction of the airways inflammation and therefore improvement of symptoms and pulmonary function.
Objectives: To determine whether macrolides are effective in the management of patients with chronic asthma.
Search strategy: We searched the Cochrane Airways Group Specialised Register of trials up to May 2005. This was also supplemented by manually searching bibliographies of previously published reviews, conference proceedings, and contacting study authors. All languages were included in the initial search.
Selection criteria: Randomised, controlled clinical trials involving both children and adult patients with chronic asthma treated with macrolides for more than 4 weeks, versus placebo.
Data collection and analysis: Two reviewers independently examined all identified articles. The full text of any potentially relevant article was reviewed independently by two reviewers.
Main results: Seven studies recruiting a total of 416 participants met the inclusion criteria. The quality of reporting of study methodology was generally low. We assembled findings from studies comparing macrolide treatment for at least 4 weeks in adult and pediatric patients treated for chronic asthma. Four studies showed a positive effect on symptoms of macrolides in different types of asthmatic patients. There were limited data available for meta-analysis. There was no significant difference in FEV1 for either parallel or crossover trials. However, there were significant differences in eosinophilic inflammation and symptoms. One large parallel group trial reported significant differences in peak flow but these differences abated within six months of treatment.
Authors' conclusions: Considering the small number of patients studied, there is insufficient evidence to support or to refute the use of macrolides in patients with chronic asthma. Further studies are needed in particular to clarify the potential role of macrolides in some subgroups of asthmatics such as those with evidence of chronic bacterial infection.