Essais OPC (critères objectifs de performance) - Discussion

Index de l'article


An approach based on the OPC methodology may represent an acceptable and scientifically valid alternative to determine the efficacy of Acupuncture. OPC may be considered when disease natural history of the disease is well known, patient population well described, in case of extensive experience with the acupuncture treatment, stable and well known standard of care, no significant new questions of safety and effectiveness, and expectation of significant positive treatment effect.

It may be appropriate to use OPC when standard of care therapy is well established, great deal is known about the natural history of the disease, underlying patient population is well described and stable (not much variability), extensive clinical history and experience with treatment type are known, and no apparent new concerns regarding effectiveness.

Consensus among clinical communities and expectation of significantly positive treatment effect are required too.

 Advantages of OPC

The OPC use offers several advantages over randomized clinical trials: smaller sample size surrogate for control group (as compared to RCT), standardized comparator for future trials, reduced cost, shortened time to completion, simpler logistic, saving time and money.

 Minimum requirements

However the determination of an OPC is not a simple task. It requires rigorous and scientifically valid methodologies. An OPC should be established by a multidisciplinary team of Traditional Chinese Medicine (TCM) practitioners, and Occidental physicians in cooperation with statisticians.

A detailed analysis of publications in peer-review journals provides a threshold value (OPC), a sort of consensus on the efficacy rate of allopathic treatments currently recognized, and should be followed by a detailed analysis on how it was derived in a peer-review journal. Collaboration with a statistician can determine the adequate sample size for the clinical trial to show whether the efficacy of acupuncture is higher, lower or equal to the allopathic treatment.

An OPC must reflect the current level of care and must be periodically re-evaluated.

It is necessary for TCM practitioners to participate in TCM consensus conferences to determine OPC for each disease or symptom, in conjunction with allopathic medical practitioners and/or published results in current Western medicine practice. 

Limitations of OPC

Using OPC does not mean standards can be relaxed. The trial must be well designed: intensive resource to develop the OPC, problems on agreeing to the final OPC value.

  • OPC may inherit all problems seen with historical controls.

 Valid historical control requires: a recent study with the same treatment; same eligibility criteria, workup, and evaluations; prognostic factors completely known and are the same in both treatment groups; no unexplained factors leading one to expect different results.

OPC needs for periodic/constant review and update. It is necessary to reassess its value after each relevant trial. OPC must reflect contemporary medical practice (temporal bias).

  • OPC may inherit all the problems associated with non-concurrent control: severe and unknown selection bias; significant challenge with missing data; problems with validity of data and analysis.

Close attention must be paid to inclusion/exclusion criteria (assumption of identical populations: group of patients with same condition, demographics, and prognostic values).

 Sham acupuncture

It is difficult to interpret the effects of sham needling and the extent to which such approaches can be used as valid controls in clinical trials. It has been shown that slight touch of the skin stimulates mechanoreceptors coupled toslow conducting unmyelinated (C) afferents, inducing a “limbic touch”' response resulting in emotional and hormonal reactions [23].

Sham acupuncture interventions are often associated with moderate nonspecific effects.

RCT‘s. Comparing real acupuncture with sham acupuncture presents small power. According to Linde et al. [24], the differentiation between specific effects of acupuncture and non-specific effects (placebo) required the recruitment of 800subjects in a double-blind randomized controlled trial in order to obtain a power of 80%, and a standardized mean difference (SMD) 0.2 for a specific outcome measure.

OPC concept has the advantage of not using minimal, superficial, sham, or “placebo” acupuncture for the control group.