Traditional Chinese medicine for airway remodelling in patients with asthma: A systematic review of randomized controlled trials

Abstract

Introduction

This systematic review aimed to evaluate the effectiveness and safety of traditional Chinese medicine (TCM) interventions for airway remodelling in patients with asthma.

Methods

A systematic search was conducted of 8 international and Chinese databases and 2 clinical trial registries from the inception of the database to March 2022. The data were analysed for the outcomes of lung function, matrix metalloproteinases-9 (MMP-9), tissue inhibitor of metalloproteinases-1 (TIMP-1), and adverse events. The Cochrane “Risk of bias” tool and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methods were used to assess the methodological quality and the certainty of the evidence. Descriptive analysis was employed to summarize the outcomes of TCM. The PROSPERO ID is CRD42022318617. This work was financially supported by the National Natural Science Foundation of China (No. 82,004,167).

Results

Twenty RCTs involving 1790 patients with asthma were included. The trials were at unclear or high risk of bias. The certainty of the evidence ranged from very low certainty to low certainty. The TCM used in each trial was different. Compared to those of conventional medicine, 9 trials showed greater effects of TCM alone or combined with conventional medicine on lung function, as indicated by the FEV₁, FVC, and FEV₁/FVC. Nine trials showed that TCM significantly reduced the expression of MMP-9 and TIMP-1. Five trials reported adverse events.

Conclusion

TCM alone or in combination with conventional medicine alleviated airway remodelling symptoms in patients with asthma. However, additional high-quality randomized trials are still needed to confirm the beneficial effectiveness of TCM.