Background: Acupuncture therapy has been widely applied all around the world. But there still lacks high-quality evidence to evaluate its clinical effects, safety and cost-effectiveness, which seriously restricts its further promotion and development. Acupuncture, as an operational intervention, is more complex than drug therapy. Factors involved in the acupuncture operation process, such as individual and interventional factors, may affect clinical effects. Purpose:s Through this systematic review, we attempt to analyze the current status of studies about the key factors influencing clinical effects, so as to provide evidence for the design of acupuncture studies. Methods: A literature research was conducted in six databases until May, 2020. Studies were screened and assessed by two authors independently. Data extraction was made after screening. We extracted the basic information of these studies, including publishing years and countries, population and factors influencing clinical effects.Results: Through the initial search in these six database, 6404 records were retrieved. After duplication and screening, a total of 355 studies were finally included in the qualitative analysis. About 88.5% of these studies were conducted in China with increasing number in the past decades, covering neurological disorders, orthopedic disorders, obstetrical and gynecological diseases, digestive diseases and so on; 239 studies focused on stimulus parameters which may influence effects, accounting for 67.3%, and 128, 44, 39, 32, 15, 11 studies discussed acupoints, patients’ pathological states, individual difference, psychological states, deqi, and other factors separately. Conclusion: There are more and more studies focusing on factors influencing acupuncture clinical effects, including stimulus parameters, acupoints, individual difference, patient pathological and psychological states. Based on this systematic review, several ignored factors should be considered for future researches, and more scientifically and objectively high quality evidence should also be proved.
From modulated noise to natural speech: The effect of stimulus parameters on the envelope following response
