A randomized controlled trial study protocol for Xiao-Qing-Long decoction in the treatment of refractory asthma

Abstract Introduction: People with refractory asthma (RA) often seek help from Chinese medicine due to dissatisfaction with conventional treatments. External cold and internal fluid syndrome is the most common type of asthma and the Chinese herbal medicine formula Xiao-Qing-Long (XQL) decoction is commonly prescribed for patients with asthma with this syndrome. However, there is no direct evidence to support the efficacy and safety of XQL decoction for RA treatment and its potential mechanism is still unclear. Methods: We propose a double-blind, placebo-controlled, randomized superiority trial. After a 2-week run-in period, 112 eligible participants will be recruited and randomly allocated to an experimental group or control group in a 1:1 ratio. Patients in the experimental group will take XQL decoction, while patients in the control group will receive a matched placebo. Symbicort Turbuhaler and Montelukast sodium tablets will be provided as the basic treatment for the 2 groups. All participants will receive 4 weeks of treatment and 12 weeks of follow-up. The primary outcome is the mean change in the asthma control test score from the baseline to 4 weeks posttreatment. The secondary outcomes include quality of life, lung function, curative effect of traditional Chinese medicine, and rescue medication used. This trial will also include analyses of the associations between intestinal microbiota and RA treatment. Any side effects of the treatment will be recorded. Discussion: The results of this trial will provide consolidated evidence of the effect of XQL decoction for RA and the potential mechanism by which XQL decoction acts, which will inform treatment options for patients with RA.