The use of pattern differentiation in WHO-registered traditional Chinese medicine trials – A systematic review

Introduction: Pattern differentiation is a critical component for traditional Chinese medicine (TCM) diagnosis and treatment. However, the issue of whether pattern differentiation is appropriately applied in TCM interventional trials, including Chinese herbal medicine (CHM) interventions and non-herbal TCM interventions, is unclear. The aim of this study was to i) systematically review the current status of pattern differentiation used in WHO-registered clinical trials for different types of TCM interventions; and ii) provide suggestions for improving the use of pattern differentiation in future clinical trial design. Methods: The World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) database was searched for all TCM interventional trials registered up to 31 December 2017. In this systematic review trials with a TCM pattern differentiation in their design were included. Descriptive statistics were collated to demonstrate the characteristics of pattern differentiation applied for different TCM interventional trials. Results: Among 2955 TCM interventional trials registered during 1999–2017, 376 (12.7%) trials included pattern differentiation. Of 376 trials, the use of pattern differentiation was identified in; –the title (30.6%), objective (50.5%), participants inclusion (100%), outcomes (43.6%) and study background (12.5%). Further, 85.4% reported the specific name of the TCM intervention, 10.6% provided the intervention's targeted pattern, 83.8% reported the specific name of the TCM pattern, 7.2% presented diagnostic criteria for the pattern studied, and 19.1% adopted a pattern-related outcome as primary outcome for evaluation. Conclusion: The reporting and application of pattern differentiation in TCM trials were inadequate and confusing, which was mainly due to lack of clarity regarding study design, objectives, diagnostic criteria and outcomes.