Clinically meaningful nocebo effect occurs in acupuncture treatment: a systematic review.
OBJECTIVE
To investigate the nocebo effect using randomized acupuncture trials that include sham and no-treatment groups.


METHODS
Electronic databases were searched to retrieve eligible trials from their inception until June 2013. Risk differences were then calculated using the acupuncture and sham groups to determine the treatment effect and the sham and no-treatment groups to determine the nocebo effect.


RESULTS
In total, 58 eligible trials were analyzed. On the basis of the rate of patients with any adverse event in 31 trials reporting available data, the treatment effect was 0.012 (95% confidence interval [CI]: 0.003, 0.021), with a number needed to harm (NNH) of 83 (95% CI: 48, 333). The nocebo effect was 0.049 (95% CI: 0.012, 0.086), with an NNH of 20 (95% CI: 12, 83). By contrast, the rate of dropouts due to adverse events in 39 trials reporting available data showed no differences for both effects. In addition, nearly 70% of the trials reported zero dropouts in the sham and no-treatment groups.


CONCLUSIONS
Our findings suggest that (1) the nocebo effect of acupuncture is clinically meaningful and (2) the rate of patients with any adverse event may be a more appropriate indicator of the nocebo effect.
Honam Research Center, Medifarm Hospital, YangYul-gil 306, Suncheon 540-300, Republic of Korea; Department of Oriental Medicine, Medifarm Hospital, YangYul-gil 306, Suncheon 540-300, Republic of Korea. Electronic address: samlungchim@hanmail.net.
Yun Hyung
YH
Koog
Honam Research Center, Medifarm Hospital, YangYul-gil 306, Suncheon 540-300, Republic of Korea; Department of Rehabilitation, Medifarm Hospital, YangYul-gil 306, Suncheon 540-300, Republic of Korea.
Jin Su
JS
Lee
Honam Research Center, Medifarm Hospital, YangYul-gil 306, Suncheon 540-300, Republic of Korea.
Hyungsun
H
Wi
D015670:Acupuncture Therapy / Q000009:adverse effects* / Q000379:methods* / Q000592:standards; D006801:Humans; D064786:Nocebo Effect; D016032:Randomized Controlled Trials as Topic / Q000009:adverse effects* / Q000379:methods* / Q000592:standards
Acupuncture; Adverse event; Dropout; Nocebo effect; Randomized trial; Systematic review