The Potential Influence of Absence of Blinding Method: Secondary Analysis From Randomized Controlled Trials Concerned Acupuncture for Depression

Background To evaluate the possibility and impact of performance and detection bias in randomized controlled trials due to lack of the blinding method. MethodsTrials assessing acupuncture for depression published by March 2020 were searched from China National Knowledge Infrastructure database. Through matching, we reassembled the trials of comparing experimental acupuncture and control acupuncture. Meta-analysis with post-treatment HAMD (Hamilton Depression Scale) of the newly reassembled trials was conducted. Changes of HAMD of all included groups were also analyzed, the between groups difference was then analyzed by t-test. All statistical analyses were performed using RevMan 5.3 software. ResultsThirteen pairs of studies were matched from 63 included trials. Re-analysis from the paired studies showed obvious difference of HAMD scales between the experimental and control acupuncture (Mean Difference was -2.95 for HAMD-17, -5.55 for HAMD-24). Re-analysis from all the included groups also showed the statistical difference between groups at four weeks of HAMD-17 (P=0.01), and four/six weeks of HAMD-24 (PConclusion Effectiveness of acupuncture for decreasing the severity of depression was superior in trials that considered acupuncture as experimental treatment, showing performance and detection bias caused by the absence of blinding method is of great significance in acupuncture trials.