Impact of long-acting muscarinic antagonists on small airways in asthma and COPD: A systematic review

The impact of wearing facemask on COPD patients: A protocol of a systematic review and meta-analysis

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a common, irreversible but preventable disease characterized by persistent respiratory symptoms. The mortality rate of COPD is predicted to reach 5.4 million by the year 2060. Despite its heavy burden on healthcare expenditure worldwide, only 15% of cases are medically identified. The potential benefits of facemask-wearing for COPD patients remain a topic of debate.

METHODS

We will conduct a systematic review of all randomized trials and non-randomized controlled trials to evaluate the impact of facemasks on COPD patients. Our review will be based on literature obtained through a comprehensive search strategy across multiple electronic databases, including the Cochrane Library, Embase, PubMed, Web of Science, the Chinese Biomedical Database (SinoMed), and China National Knowledge Infrastructure (CNKI), with no restrictions on language or date of publication. Two independent researchers will extract and assess all relevant data using pre-designed data extraction forms. The included studies will be assessed using the Cochrane RoB2 tool and the suggested risk of bias criteria proposed by the Effective Practice and Organization of Care reviews group of the Cochrane collaboration. The quality of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. We will use Review Manager 5.4 software for statistical analysis.

DISCUSSION

In the context of COVID-19, it is important for COPD patients to wear facemasks. This study aims to conduct a comprehensive and systematic assessment of the impact of facemasks on the physiology and activity of COPD patients.

TRIAL REGISTRATION

PROSPERO registration number CRD42022326265.

Residual Dyspnea May Predict Small Airways Dysfunction and Poor Responsiveness to Single-Inhaler Triple Therapy in Asthmatic Patients

PURPOSE

Recently, single-inhaler triple therapy (SITT) has demonstrated efficacy in patients with uncontrolled asthma who were symptomatic despite treatment with inhaled corticosteroids/long-acting β2 agonists. However, the characteristics of patients who benefit from SITT remain unclear in the real-world. The aim of this study was to examine the predictors of responsiveness to SITT in patients with asthma.

PATIENTS AND METHODS

A total of 45 patients with asthma who had regularly visited our respiratory clinic and were started on SITT from March 2019 to March 2021 were retrospectively analyzed. Patients' demographic characteristics, residual respiratory symptoms, type 2 biomarkers, and lung function before SITT were assessed from the patients' medical records. Predictors of responsiveness to four-week SITT were evaluated in these patients. The definition of responders was based on the physician-assessed global evaluation of treatment effectiveness.

RESULTS

Thirty-four (75%) of 45 patients were identified as responders to SITT. Non-responders showed significantly lower forced vital capacity (FVC) (%predicted) values, and complained of dyspnea more frequently than responders before SITT (p = 0.01 and p = 0.02, respectively). There were no significant differences in demographic characteristics and type 2 biomarkers between responders and non-responders. Clinical predictors of poor response to SITT were residual dyspnea (OR = 0.14, p = 0.02), low FVC (%predicted) values (OR = 1.05, p = 0.01), and FVC (%predicted) <80% (OR = 0.11, p = 0.02). Multivariate analysis showed that poor response to SITT was associated with residual dyspnea before SITT (OR = 0.14, p = 0.02). On the other hand, patients with residual dyspnea had significantly lower FEF_25-75 (%predicted) values than patients without residual dyspnea before SITT (p = 0.04).

CONCLUSION

Residual dyspnea, reflecting small airways dysfunction, may predict poor responsiveness to short-term SITT in patients with asthma.

The impact of long-acting muscarinic antagonists on mucus hypersecretion and cough in chronic obstructive pulmonary disease: a systematic review

Patients suffering from chronic obstructive pulmonary disease (COPD) clinically manifest airway mucus hypersecretion as sputum expectoration and cough. Evidence accumulated in the past decade has shown that the cholinergic system not only regulates airway smooth muscle contraction but also the activity of inflammatory and airway epithelial cells, including goblet cells, and submucosal gland activity. Long-acting muscarinic antagonists (LAMAs) with the most favourable M₃/M₂ muscarinic acetylcholine (ACh) receptors residency properties are not only excellent bronchodilators but potentially also mucus-modifying agents, able to positively impact on mucus hypersecretion and cough. The aim of this systematic review was to investigate the impact of LAMAs on mucus hypersecretion and cough in COPD patients. The evidence confirmed that LAMAs, mainly tiotropium and aclidinium, improved sputum production and cough in moderate to severe COPD. Thus, LAMAs not only antagonise the ACh-induced bronchoconstriction of the airways but also appear to limit the production of mucus secreted in response to ACh by airway goblet cells and/or submucosal glands. Further clinical studies are necessary to evaluate the impact of LAMAs exclusively on sputum symptoms and cough as primary end-points and to investigate whether LAMAs have a modulatory action on the rheological properties of mucus.