Abstract: We included 14 parallel-group RCTs and one cross-over RCT with interventions lasting from 8 weeks to 24 months. Of 11 adult studies with 690 participants, six used azithromycin, four roxithromycin, and one erythromycin. Four studies with 190 children used either azithromycin, clarithromycin, erythromycin, or roxithromycin. We included nine adult studies in our comparison between macrolides and placebo and two in our comparison with no intervention. We included one study with children in our comparison between macrolides and placebo and one in our comparison with no intervention. In adults, macrolides reduced exacerbation frequency to a greater extent than placebo (OR 0.34, 95% confidence interval (CI) 0.22 to 0.54; 341 participants; three studies; I2 = 65%; moderate-quality evidence). This translates to a number needed to treat for an additional beneficial outcome of 4 (95% CI 3 to 8). Data show no differences in exacerbation frequency between use of macrolides (OR 0.31, 95% CI 0.08 to 1.15; 43 participants; one study; moderate-quality evidence) and no intervention. Macrolides were also associated with a significantly better quality of life compared with placebo (MD -8.90, 95% CI -13.13 to -4.67; 68 participants; one study; moderate-quality evidence). We found no evidence of a reduction in hospitalisations (OR 0.56, 95% CI 0.19 to 1.62; 151 participants; two studies; I2 = 0%; low-quality evidence), in the number of participants with serious adverse events, including pneumonia, respiratory and non-respiratory infections, haemoptysis, and gastroenteritis (OR 0.49, 95% CI 0.20 to 1.23; 326 participants; three studies; I2 = 0%; low-quality evidence), or in the number experiencing adverse events (OR 0.83, 95% CI 0.51 to 1.35; 435 participants; five studies; I2 = 28%) in adults with macrolides compared with placebo. In children, exacerbation frequency was reduced more with macrolides than with placebo (IRR 0.50, 95% CI 0.35 to 0.71; 89 children; one study; low-quality evidence). However there was no significant difference in this age group with regard to: hospitalisations (OR 0.28, 95% CI 0.07 to 1.11; 89 children; one study; low-quality evidence), serious adverse events, defined within the study as exacerbations of bronchiectasis or investigations related to bronchiectasis (OR 0.43, 95% CI 0.17 to 1.05; 89 children; one study; low-quality evidence), or adverse events (OR 0.78, 95% CI 0.33 to 1.83; 89 children; one study), in those receiving macrolides compared to placebo. The same study reported an increase in macrolide-resistant bacteria (OR 7.13, 95% CI 2.13 to 23.79; 89 children; one study), an increase in resistance to Streptococcus pneumoniae (OR 13.20, 95% CI 1.61 to 108.19; 89 children; one study), and an increase in resistance to Staphylococcus aureus (OR 4.16, 95% CI 1.06 to 16.32; 89 children; one study) with macrolides compared with placebo. Quality of life was not reported in the studies with children. Long-term macrolide therapy may reduce the frequency of exacerbations and improve quality of life, although supporting evidence is derived mainly from studies of azithromycin, rather than other macrolides, and predominantly among adults rather than children. However, macrolides should be used with caution, as limited data indicate an associated increase in microbial resistance. Macrolides are associated with increased risk of cardiovascular death and other serious adverse events in other populations, and available data cannot exclude a similar risk among patients with bronchiectasis.

Plain-language summary: We found 15 studies that compared macrolides with placebo (a substance or treatment with no benefit) or no intervention. Eleven studies involved 690 adults (aged 18 years and older) and four studies involved 190 children. Among adults, six used azithromycin, four roxithromycin, and one erythromycin. The four studies with children used azithromycin, clarithromycin, erythromycin, or roxithromycin. This review is current to January 2018. The studies on azithromycin reported improved quality of life in adults. We do not have sufficient evidence from other macrolides to make a robust judgement on their use, and we similarly have insufficient evidence from children to draw clear conclusions. Although we found only a few trials, they do show a possible increase in antibiotic resistance. Antibiotic resistance is seen when an antibiotic becomes less effective at killing the bacteria causing the chest infection. We know that macrolides are associated with higher risk of cardiovascular death and other serious adverse events when they are used to treat other conditions. The data in our review suggest it is possible that people with bronchiectasis are at risk for these adverse effects when taking macrolides. Generally the limited number of studies evaluating macrolides and the variation among them indicate that we cannot be sure of the overall effect of their use in bronchiectasis. Further high-quality studies are needed to examine the role of long-term macrolide antibiotics in the treatment of adults and children with bronchiectasis.