Mucus Plugging Across Multiple Chronic Respiratory Diseases: A Systematic Review and Meta-analysis.

In 30 seconds

This systematic review and meta-analysis assessed mucus-plug prevalence, clinical characteristics and outcomes across chronic respiratory diseases, including asthma, COPD and cystic fibrosis. Across 33 studies, pooled prevalence was 63% (95%CI 52%, 74%) in asthma, 47% (95% CI 38%, 55%) in COPD and 63% (95% CI 46%, 81%) in cystic fibrosis. Mucus plugging was associated with disease-specific clinical features and, in COPD, with higher risks of acute exacerbation and mortality, prolonged hospital stays and greater hospitalization costs. The findings identify mucus plugging as a common feature associated with clinically relevant outcomes, but do not establish causality.

Key findings

• Pooled mucus-plug prevalence was 63% (95%CI 52%, 74%) in asthma, 47% (95% CI 38%, 55%) in COPD and 63% (95% CI 46%, 81%) in cystic fibrosis.
• In asthma, mucus plugging was associated with higher eosinophil counts and FeNO, and lower FEV₁% and FEV₁/FVC.
• In COPD, mucus plugging was associated with older age and lower BMI, FEV₁%, FVC% and FEV₁/FVC (all p < 0.05).
• In COPD, mucus plugging was associated with higher risk of acute exacerbation and mortality, prolonged hospital stays and increased hospitalization costs.

Why it matters

Mucus plugging was common across the diseases reviewed and was associated with lung-function and inflammatory features, as well as adverse outcomes in COPD. Recognising these associations may help frame mucus plugging as a clinically relevant feature for research into disease assessment and prognosis. The review supports further investigation, while its findings do not show that mucus plugging causes these outcomes or that targeting it improves them.

What to keep in mind

The review reports heterogeneity across studies, with several clinical variables contributing to it in asthma and COPD. The abstract does not provide pooled effect estimates for the reported outcome associations.