Target dIsease-Guided placEbo-contRolled (TIGER) design: a novel method for clinical trials of acupuncture

At present, the design of an ideal placebo control in acupuncture studies challenges researchers. Previously devised sham acupuncture techniques have reported various imperfections; therefore, the specific effects of acupuncture cannot be accurately examined in clinical trials primarily because of interferences from the placebo effects.

Guided by evidence-based medicine (EBM) theories, we have made an initial attempt to establish a set of control methods for use in acupuncture studies, which is named the target disease-guided placebo-controlled (TIGER) design. In a trial using the TIGER design, participants suffering simultaneously from a predefined target disease and a pseudo target disease will be recruited and randomized to receive identical acupuncture intervention measures. As a result, the interventions not only appear the same but also produce the same stimulations in both groups. The patients in the treatment group will be informed of the actual target disease that the treatment aims for, whereas patients in the control group will be informed that the treatment is for the pseudotarget disease. It is speculated that no psychological response will be aroused in the control group. During data analysis, changes in the outcome measures of the patients in the control groupreveal the real therapeutic effect of acupuncture, and those of patients in the treatment group show both the real and placebo acupuncture effect. In this article, we explain how to put this design into use in a planned randomized clinical trial of acupuncture for the treatment of migraine.

This approach can eliminate the acupuncture placebo effect in the control group that may confound trial results. It is possible to observe the specific and placebo effects of acupuncture for the target disease separately using the TIGER design.

The proposed TIGER design has limitations. It is designed for clinical studies focusing on the specific effects of acupuncture, and it needs to be tested and verified for practicality and feasibility in various clinical research settings.