Mucoactive agents in bronchiectasis: a systematic review and meta-analysis

Mucoactive agents aim to improve mucociliary clearance in bronchiectasis, disrupting the cycle of impaired clearance, infection and inflammation. Registry data show 28% of patients use these agents, but prescribing varies due to limited evidence. We aimed to update evidence on mucoactive agents' effects in adults with bronchiectasis.

We conducted a systematic review and meta-analysis, searching Medline, Embase, CENTRAL and trial registries to 1 October 2025. Eligible studies included adults with bronchiectasis, evaluating any mucoactive agent versus placebo or control. Cystic fibrosis and paediatric studies were excluded. The primary outcome was exacerbation frequency; secondary outcomes included lung function, quality of life and adverse events.

From 1512 records, 24 studies (20 randomised, four observational: n=7051) evaluated eight mucoactive agents (ambroxol, bromhexine, carbocisteine, erdosteine, hypertonic saline, mannitol, N-acetylcysteine, rhDNase). Most trials had high or some risk of bias. Seven randomised studies (n=1259) reported exacerbations; pooled analysis did not demonstrate a statistically significant difference in annualised exacerbation incidence (mean difference -0.40 per patient per year, 95% CI -1.04-0.24; p=0.22; I²=91%; very low certainty). Nine studies (n=767) reported percent predicted forced expiratory volume in 1 s (FEV₁ % pred), showing a small mean increase of 3.23% (95% CI 0.31-6.15; p=0.03; I²=69.9%; very low certainty). Pooled analyses did not demonstrate significant differences for other spirometry measures, quality of life or adverse events.

Pooled evidence did not show a reduction in exacerbations and FEV₁ % pred improvements were small. Evidence certainty was low/very low, meaning overall clinical benefit remains uncertain, highlighting the need for targeted trials of specific agents and subgroups.