BackgroundIt has been argued that placebos may not have important clinical impacts in general. However, there is increasing evidence of a publication bias among trials published in journals. Therefore, we explored the potential for publication bias in randomized trials with active treatment, placebo, and no-treatment groups.MethodsThree-armed randomized trials of acupuncture, acupoint stimulation, and transcutaneous electrical stimulation were obtained from electronic databases. Effect sizes between treatment and placebo groups were calculated for treatment effect, and effect sizes between placebo and no-treatment groups were calculated for placebo effect. All data were then analyzed for publication bias.ResultsFor the treatment effect, small trials with fewer than 100 patients per arm showed more benefits than large trials with at least 100 patients per arm in acupuncture and acupoint stimulation. For the placebo effect, no differences were found between large and small trials. Further analyses showed that the treatment effect in acupuncture and acupoint stimulation may be subject to publication bias because study design and any known factors of heterogeneity were not associated with the small study effects. In the simulation, the magnitude of the placebo effect was smaller than that calculated after considering publication bias.ConclusionsRandomized three-armed trials, which are necessary for estimating the placebo effect, may be subject to publication bias. If the magnitude of the placebo effect is assessed in an intervention, the potential for publication bias should be investigated using data related to the treatment effect.
Knee osteoarthritis is the most common form of joint disease and is a major cause of pain and physical disability among the elderly. Although, numerous treatments have been developed to treat osteoarthritis, no definitive treatments with high efficacy and low risk have been identified until now. In recent years, it has been reported that nutraceuticals may be good candidates for the management of knee osteoarthritis. This paper describes the efficacy of nutraceuticals for treating knee osteoarthritis in terms of pain and structural change. To accomplish this, this paper reports on the analysis of randomized, placebo-controlled, clinical trials that were published prior to December 2011.
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