Sanfu herbal patch applied at acupoints in patients with bronchial asthma: statistical analysis plan for a randomised controlled trial

BACKGROUND: Sanfu herbal patch (SHP) is widely used in the prevention and treatment of bronchial asthma in China, but its efficacy and mechanism of action are not completely clear. This trial aims to determine the efficacy of SHP and the underlying mechanism. METHODS/DESIGN: We will conduct a multi-centre parallel randomised controlled trial consisting of 72 participants with bronchial asthma recruited and randomly allocated at a ratio of 1:1 into two groups. The patients in one group will receive three courses of SHP treatment, and the patients in the other group will receive placebo treatment, with 24 weeks of follow-up evaluation for both groups. The primary outcome, i.e. forced expiratory volume in the first second (FEV1), which refers to the change in FEV1 from the beginning of the baseline to the end of 3 treatment sessions (TSs), will be assessed and compared via Student’s t test or the Mann–Whitney U test. Other outcomes will include questionnaire surveys and laboratory indicators. Detailed and complete statistical analyses in a double-blinded fashion will be provided for evaluating this trial. DISCUSSION: The data we obtain will be examined based on the above statistical analysis, which will help to reduce the risk of external reporting bias and data-driven results. TRIAL REGISTRATION: Chinese Clinical Trial Registry (http://www.chictr.org.cn), ChiCTR1900024616. Registered on 19 July 2019. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-022-06990-7.