Syndrome pattern and its application in parallel randomized controlled trials.

Syndrome pattern (SP) is a core concept of Chinese medicine (CM) and is used to diagnose and treat patients based on an overall analysis of symptoms and signs. This study aimed to systematically review randomized controlled trials (RCTs) using the SP concept and to demonstrate how the SP concept could be applied to the study design of parallel RCTs, considering a gold standard of clinical research. After conducting a brief systematic review by way of a PubMed search, we analyzed how the SP concept was applied to the design of RCT in a CM herbal medicine trial. We then formulated possible research questions, applied the SP concept to answer the research questions, and suggested possible RCT designs to be used for conducting future trials. Fourteen RCTs were included in our systematic review, and three key points of the SP concept were formulated for the design of parallel RCTs: the time point of SP diagnosis between before and after randomization; the relationship between the international classification of diseases (ICD) and SP for the inclusion of target population; and the proper diagnostic method of SP. In this study, we formulated three possible research questions and then suggested perspectives for five possible RCT models arrived at using SP concepts. Future trials applying SP concept to RCTs should overcome the shortcomings of past SP trials, moving CM forward from experience-based to evidence-based medicine.