Blinding Indices and Blinding Scenarios of Practitioners and Patients with Acupuncture Needles for Double Blinding

In acupuncture studies, it is necessary to expose blinded patients to control devices such as placebo/sham needles with a blunt tip, which allows the skin to be touched but not penetrated. Several recent systematic reviews have investigated the success of patient blinding with Streitberger, Park and Takakura placebo/sham needles in a series of validation and clinical trials using Bang’s blinding index (BI),1 2 which indicates the degree of potential unblinding beyond balance for each arm of real and placebo treatment.2 In a review papers, it was pointed out that the BIs for Takakura needles for double blinding were unavailable.1 Further, for study Ib (see table 1),3 Moroz et al reported the BIs of patients calculated from the number of subjects who did, or did not, experience the sensation of skin penetration,2 which differed from the BIs calculated from the number of correct and incorrect guesses, even though we reported that “none of the subjects commented in the questionnaire that they had received a non-penetrating needle”. …