MD, PhD, FMedSci, FRSB, FRCP, FRCPEd

If you want to scientifically investigate this question, it might be a good idea NOT to start with the following sentence: “Auricular acupuncture (AA) is effective in the treatment of preoperative anxiety”. Yet, this is exactly what the authors did in their recent publication.

The aim of this new study was to investigate whether AA can reduce exam anxiety as compared to placebo and no intervention. Forty-four medical students were randomized to receive AA, placebo, or no intervention in a crossover manner. Subsequently they completed three comparable oral anatomy exams with an interval of one month between the exams/interventions.

A licensed acupuncturist with more than five years of experience with this technique applied AA at the acupuncture points MA-IC1 (Lung), MA-TF1 (ear Shenmen), MA-SC (Kidney), MA-AT1 (Subcortex) and MA-TG (Adrenal gland) bilaterally. Indwelling fixed ‘New Pyonex’ needles embedded in a skin-coloured adhesive tape were used for AA. The participants were instructed by the acupuncturist to stimulate the auricular needles for 3–5 minutes, if they felt anxious. For the placebo procedure, ‘New Pyonex’ placebo needles were attached to five sites on the helix of the auricle bilaterally. ‘New Pyonex’ placebo needles have the same appearance as AA needles but consist of self-adhesive tape only. In order to avoid potential physiologic effects of acupressure, the participants were not instructed to stimulate the attached ‘New Pyonex’ placebo needles. AA and placebo needles were left in situ until the next day and were removed out of sight of the participants after the exam by the investigator, who was not involved in acupuncture procedure

Levels of anxiety were measured using a visual analogue scale before and after each intervention as well as before each exam. Additional measures included the State-Trait-Anxiety Inventory, duration of sleep at night, blood pressure, heart rate and the extent of participant blinding.

All included participants finished the study. Anxiety levels were reduced after AA and placebo intervention compared to baseline and the no intervention condition (p < 0.003). Moreover, AA was also better at reducing anxiety than placebo in the evening before the exam (p = 0.018). Participants were able to distinguish between AA and placebo intervention.

The authors concluded that both auricular acupuncture and placebo procedure were shown to be effective in reducing levels of exam anxiety in medical students. The superiority of verum AA over placebo AA and no intervention is considered to be due to stimulation of cranial nerves, but may have been increased in effect by insufficient participant blinding.

Here are just three of the major concerns I have about this study:

  • The trial design seems odd: a crossover study can only work well, if there is a stable baseline. This may not be the case with three consecutive exams; the anxiety experienced by students is bound to get less as time goes by. I think anyone who has passed a series of exams will confirm that there is a large degree of habituation.
  • It seems inadequate to employ just one acupuncturist; it means that the trial might end up testing not acupuncture per se but the skills of the therapist.
  • The placebo used for this study cannot possibly have fooled anyone into believing that it was real AA; volunteers were not even instructed to ‘stimulate’ the placebo devices. The difference to the ‘real thing’ must have been very clear to all involved. This means that the control for placebo-effects was woefully incomplete. In turn, this means that the observed outcomes are most likely due to residual bias.

In view of these concerns, allow me to re-phrase the authors’ conclusions:

THE RESULTS OF THIS POORLY-DESIGNED STUDY ARE DIFFICULT TO INTERPRET. MOST LIKELY THEY SHOW THAT ACUPUNCTURE IS NOT EFFECTIVE BUT MERELY WORKS THROUGH A PLACEBO-RESPONSE.

11 Responses to Does auricular acupuncture reduce anxiety? A new study says YES, but I say NO

  • Yet another study showing no clear evidence that acupuncture is clinically superior to placebo. The statistical significance found could certainly be the result of blinding deficiencies.

    Considering the inherent implausibility of the ear’s supposed resemblance to a foetus as being anything more meaningful than imagination/coincidence, the most reasonable and therefore most likely explanation for the statistical result is bias.

  • I never tire of watching conjurors who can pull a rabbit out of a hat, and many similar things. I thoroughly enjoy watching because, despite knowing that it is trickery, I do not have enough knowledge to figure out the method.

    With that in mind, consider the final N values for the study being discussed: AA 12; Placebo 13; NI 15; total 40. The study stated that the initial number of participants was previously derived in reference 12: Klausenitz C, Hesse T, Hacker H, Hahnenkamp K, Usichenko T. Auricular acupuncture for pre-exam anxiety in medical students: a prospective observational pilot investigation.

    Abstract
    Objective Auricular acupuncture (AA) is effective for the treatment of preoperative anxiety. We aimed to study the feasibility and effects of AA on exam anxiety in a prospective observational pilot study.

    Results Ten students (all female) were included in the final analysis. All tolerated the needles well and stated they would wish to receive AA again for exam anxiety in the future. Exam anxiety measured using both STAI and VAS-100 decreased by almost 20% after AA.

    Conclusions AA was well accepted, the outcome measurement was feasible, and the results have facilitated the calculation of the sample size for a subsequent randomised controlled trial.

    Note in particular the statement: “Auricular acupuncture (AA) is effective for the treatment of preoperative anxiety”. Clearly, the prior probability used in both the pilot investigation then the study (being discussed) was assumed to be 1 [“is effective”]. The abstract of the study being discussed starts with exactly the same statement.

    It seems to me that the results of this study were known in advance — just as a conjuror knows in advance that the rabbit will indeed be in the hat at the finale. So, my question is: What was the the trick that was used to guarantee a positive result from the final N values that are so small?

    • Perhaps the prior confidence of those directing the trial that AA worked was communicated to participants. Given their complete confidence why did they bother with the trial at all?

  • I don’t know but I would find it nice to have a summary for ordinary people on how to identify bad study designs an co.

    Does anybody wrote such thing? Maybe EE or SBM’?

    • I am afraid that is a big ask – critical assessment of clinical trials is too complex to put in a few words. the best advice I can give is to follow this blog, particularly those posts which are specifically about evaluating specific trials.

      • I know but you have to accept, that people want things easy. So at least we should tell them. Ok you need at least 1. one better two or more (depending on the approach) control groups,
        2. double or triple blinded,
        3. placebo controlled
        4. lets say about 100 participants.

        Furthermore people understand that one study doesn’t tell you necessary the truth, you need more than one.
        We also need to fight the misconception of the p-Value in people. At least we need to explain, that even if you were very carefully with your study the result has a x% chance of being wrong.

        Really I am talking with teacher about these things and they have no clue about the stuff we are talking about here.

        It needs to be more easily explained and it needs to start in school but if teachers have no clue…

    • A very readable book is How to Read a Paper : The Basics of Evidence-Based Medicine by Prof Trisha Greenhalgh. A bit pricey perhaps, but well worth it – you may be able to get it cheaper (particularly earlier editions) or from a library.

      • yes, a good book! but is it something for a complete novice?

        • That depends on whether or not the ‘complete novice’ is willing to learn.

          I shall purchase, then try my very best to properly understand, both:
          Real Secrets of Alternative Medicine: An Exposé, by Dr. Richard Rawlins;
          How to Read a Paper: The Basics of Evidence-Based Medicine, by Dr. Trisha Greenhalgh.

          I’m quite good at teaching ‘complete novices’ because I clearly remember, with profound humility, my childhood.

  • So now is a good time to get my ears pierced?

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