Blind Patients with Different Characteristics and Experiences When Treated by Several Therapists

Copyright © 2011 Anna Enblom et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Little is known which factors influence the blinding in acupuncture studies. Aim. To investigate if blinding varied between patients with different characteristics receiving verum or sham acupuncture. Methods. We randomised cancer patients to verum (n = 109) or sham acupuncture (n = 106) with a nonpenetrating telescopic sham needle for nausea. Level of blinding was compared between different sub-groups of patients using Bang’s blinding index (BI) ranged −1 to 1 (−1 = all state the opposite treatment, 1 = all identify treatment). Results. Most patients in the verum (74 of 95; 78%, BI 0.72) and the sham (68 of 95; 72%, BI −0.60). acupuncture group believed they had received verum acupuncture. The probability for a patient to believ