Nurses, April 2005 Journal Scan
From
Evaluation & The Health Professions
March 2005 ( Volume 28 , Number 1 )
Is Acupuncture Analgesia an Expectancy Effect? Preliminary Evidence Based on Participants' Perceived Assignments in Two Placebo-Controlled Trials
Bausell RB, Lao L, Bergman S, Lee WL, Berman BM
Evaluation & The Health Professions. 2005; 28 (1) : 9-26
Complementary and alternative medicine therapies have been criticized as nothing more than placebo by a variety of researchers. This has led to increased interest in the study of the placebo effect itself. Behavioral research suggests that both patients' expectations regarding a treatment's potential therapeutic benefits and operant conditioning play central roles in whether an analgesic treatment is effective. How placebos produce analgesia is not clear because a credible placebo and a no-treatment control are necessary to separate out placebo effects from other clinical trial artifacts such as regression toward the mean and natural history.
The purpose of this research is to contrast the analgesic efficacy of acupuncture following dental surgery with the analgesic effects based on the expectation of benefit in 2 independently conducted placebo-controlled trials evaluating acupuncture as an adjunctive therapy for dental surgery.
Both research trials used pain following dental surgery as the outcome variable, and both included a blinding check to ascertain patients' beliefs regarding which treatment they were receiving. The credibility of acupuncture randomized control trials is "inextricably linked with the credibility of its control groups because (1) patients who believe in the therapy would be expected to be more likely to volunteer for a trial evaluating it, (b) this expectancy is known to possess an analgesic effect of its own, and (c) it is extremely difficult to prevent patients from knowing whether or not needles are being inserted in their bodies." The research trials, therefore, were designed not only to evaluate the analgesic efficacy of acupuncture in comparison with different placebo conditions but also to assess the degree to which these sham procedures were distinguishable from the actual therapy they were designed to mimic. Because the masking check employed for this purpose asked which treatment (real or placebo) patients believed that they were receiving throughout their treatment, "a rare opportunity was created to directly contrast the analgesic benefit derived from the therapy with the analgesic benefits based on the expectation of benefit."
In the study, the patient's eyes were all covered so they could only feel either the insertion or sham insertions. The true acupuncture cases employed the insertion of acupuncture needles based upon traditional Chinese medicine: 3 in the face and 1 in the hand. A sham noninsertion was made at the medial aspect of the knee. Placebo 1 used a sham noninsertion adjacent to acupuncture points; distal sham shallow insertion at a place that was not really an acupuncture point. Placebo 2 used a sham shallow insertion adjacent to acupuncture points and the distal sham noninsertion at the knee. Following the administration of the experimental conditions, each patient was given a masking check where they were asked, "Which treatment do you believe you received?" The possible responses were (a) acupuncture, (b) placebo/sham acupuncture, and (c) uncertain. Pain assessments were then given immediately and on a fixed, 15-minute schedule thereafter for 6 hours. In those cases in which the participant reported experiencing moderate pain, the same acupuncture treatment was administered for a second time followed by a second blinding check. At this point, the pain assessments were resumed for 2 hours unless the patient requested a rescue medication (Tylenol No. 3 with codeine). The primary outcome was pain conceptualized in 2 ways: (a) pain-free time from the initial acupuncture session until the reporting of moderate or severe pain and (b) the mean of all pain assessed prior to the second acupuncture session.
No statistically significant differences were observed among the 3 groups (acupuncture vs either of the 2 placebo conditions) with respect to either the average amount of pain experienced or time to experience moderate to severe pain in their experiment separately or when their data were combined. "This implied that acupuncture was not effective for reducing pain following dental surgery."
Although there were no statistically significant analgesic effects observed between the acupuncture and placebo groups, "participants in both experiments who believed they received real acupuncture reported significantly less pain than patients who believed that they received a placebo. Patients' beliefs regarding the receipt of acupuncture bore a stronger relationship to pain than any specific action possessed by acupuncture."
Detailed statistical analysis is provided. "These results support the importance of both employing credible controls for the placebo effect in clinical trials and also the need to evaluate the credibility of those controls."
Editor's Comment: This article reports on a study funded by the National Center for Complementary and Alternative Medicine, National Institutes of Health. It is a sophisticated piece of research with methodologic rigor in both design and analysis that has produced thought-provoking findings. As such, it contributes valid information that helps clinicians think about the value of placebos.
Might this information influence practice? Perhaps the degree of confidence that healthcare providers employ in prescribing treatment for their patients has an impact on whether patients believe it will be helpful to them. The days of, "Here, see if this prescription will help," might be replaced with, "Here, you'll probably get relief if you take this preparation."
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Refugio Manuel Rochin
As the saying : Innocent Until Proven Guilty
So the saying : Believe Until Unbelievable !
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