The rescue intervention strategy for asthma patients under severe air pollution: a protocol for a single-centre prospective randomized controlled trial.

BACKGROUND Asthma is a common chronic airway inflammatory disease. Exacerbations of asthma not only accelerate the progression of the disease but also increase the incidence of hospitalization and death. Studies have shown that air pollution is a high-risk factor for asthma exacerbations. However, few treatment strategies have been recommended to reduce the risk of severe air pollution-related asthma exacerbations. METHODS/DESIGN This is a single-centre, prospective, randomized and standard treatment parallel control clinical trial. Seventy-two asthma patients in the nonexacerbation stage according to GINA guidelines 2017 will be recruited and randomized into the rescue intervention strategy (RIS) group and control group. Original treatments for the participants will include no use of inhaled medicine, the use of short-acting β-agonists (SABA) on demand or the use of budesonide/formoterol (160 μg/4.5 μg/dose, 1-2 dose/time, b.i.d.). The rescue intervention strategy for the RIS group will be budesonide/formoterol plus the original treatment until the severe pollution ends (air quality index, AQI < 200). The control group will maintain the original treatment. The follow-up observation period will last 1 year. The primary outcome is the frequency of asthma exacerbations per year. Secondary outcomes include the mean number of unplanned outpatient visits, emergency visits, hospitalizations, medical costs and mortality caused by asthma exacerbations per patient per year. DISCUSSION The results of this trial will provide a novel strategy to guide clinical practice in decreasing the risk of asthma exacerbations under severe air pollution. TRIAL REGISTRATION ChiCTR ChiCTR1900026757 . Registered on 20 October 2019-retrospectively registered.