Background: The practice of traditional Chinese medicine (TCM) has a profound history in many Asian countries. TCM syndrome is a set of characteristic physical signs and symptoms shared by a group of patients. Syndrome diagnosis and treatment assignment according to the identified TCM syndrome is a long-held practice of Chinese medicine. Owing to its distinctive way of interpreting illness and administering care, medical practitioners not well educated in TCM theories and practices are generally incapable of giving out prescriptions for Chinese patent drugs. Currently, the existence of a multitude of Chinese patent drugs marked with largely identical indications is further complicating this situation.
Methods: In this multicenter, randomized, controlled, double-blind, double-dummy clinical trial, in which we will use the comparative effectiveness research method, we will compare the efficacy of two commonly used Chinese patent medicines for angina patients diagnosed with qi deficiency and blood stasis syndrome. A total of 160 patients will be recruited and randomly assigned to receive either (1) QiShenYiQi dripping pills, Tongxinluo placebo and routine medication or (2) Tongxinluo capsules, QiShenYiQi placebo and routine medication. These treatment regimens will be carried out for 4 weeks, followed by a 10-day washout period and a 4-week crossover phase in which the treatments in the two patient groups will be exchanged. Patients will be allowed to choose symptoms that matter most to them and will be grouped accordingly. Patient-reported outcomes such as the Seattle Angina Questionnaire score and the 15-point Likert scale score will be measured and reported. The minimally clinical important difference will be calculated and used for efficacy assessment, and correspondence analysis will be performed to identify the best indications for each drug.
Discussion: The goal of the study is to establish a methodology for the precise identification of the characteristic indications for which a Chinese patent drug is most effective. The findings of this study will inform the practicality of the proposed evaluation method.
Trial registration: Chinese clinical trials register Chi CTRTTRCC13003732.