Should systematic reviews assess the risk of bias from sham–placebo acupuncture control procedures?

A problem acupuncture research has to face is the concept of a control group. If, in control groups, non-acupoint needling is done, physiological acupuncture effects are implied. Therefore the effects shown in this group are often close to those shown in the acupuncture group. In other trials, control groups have received obviously different treatments, such as transcutaneous electrical nervous stimulation or TENS-laser treatment; it is not clear if the effects of acupuncture are due only to the psychological effects of the treatment. We developed a placebo acupuncture needle, with which it should be possible to simulate an acupuncture procedure without penetrating the skin. In a cross-over experiment with 60 volunteers we tested whether needling with the placebo needle feels any different from real acupuncture. Of 60 volunteers, 54 felt a penetration with acupuncture (mean visual analogue scale [VAS] 13.4; SD 10.58) and 47 felt it with placebo (VAS 8.86; SD 10.55), 34 felt a dull pain sensation (DEQI) with acupuncture and 13 with placebo. None of the volunteers suspected that the needle may not have penetrated the skin. The placebo needle is sufficiently credible to be used in investigations of the effects of acupuncture. Show more

Acupuncture is widely used by patients with chronic pain although there is little evidence of its effectiveness. We investigated the efficacy of acupuncture compared with minimal acupuncture and with no acupuncture in patients with osteoarthritis of the knee. Patients with chronic osteoarthritis of the knee (Kellgren grade < or =2) were randomly assigned to acupuncture (n=150), minimal acupuncture (superficial needling at non-acupuncture points; n=76), or a waiting list control (n=74). Specialised physicians, in 28 outpatient centres, administered acupuncture and minimal acupuncture in 12 sessions over 8 weeks. Patients completed standard questionnaires at baseline and after 8 weeks, 26 weeks, and 52 weeks. The primary outcome was the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index at the end of week 8 (adjusted for baseline score). All main analyses were by intention to treat. 294 patients were enrolled from March 6, 2002, to January 17, 2003; eight patients were lost to follow-up after randomisation, but were included in the final analysis. The mean baseline-adjusted WOMAC index at week 8 was 26.9 (SE 1.4) in the acupuncture group, 35.8 (1.9) in the minimal acupuncture group, and 49.6 (2.0) in the waiting list group (treatment difference acupuncture vs minimal acupuncture -8.8, [95% CI -13.5 to -4.2], p=0.0002; acupuncture vs waiting list -22.7 [-27.5 to -17.9], p<0.0001). After 52 weeks the difference between the acupuncture and minimal acupuncture groups was no longer significant (p=0.08). After 8 weeks of treatment, pain and joint function are improved more with acupuncture than with minimal acupuncture or no acupuncture in patients with osteoarthritis of the knee. However, this benefit decreases over time. Show more

Controversy remains regarding the mechanisms of acupuncture analgesia. A prevailing theory, largely unproven in humans, is that it involves the activation of endogenous opioid antinociceptive systems and mu-opioid receptors (MORs). This is also a neurotransmitter system that mediates the effects of placebo-induced analgesia. This overlap in potential mechanisms may explain the lack of differentiation between traditional acupuncture and either non-traditional or sham acupuncture in multiple controlled clinical trials. We compared both short- and long-term effects of traditional Chinese acupuncture (TA) versus sham acupuncture (SA) treatment on in vivo MOR binding availability in chronic pain patients diagnosed with fibromyalgia (FM). Patients were randomized to receive either TA or SA treatment over the course of 4 weeks. Positron emission tomography (PET) with (11)C-carfentanil was performed once during the first treatment session and then repeated a month later following the eighth treatment. Acupuncture therapy evoked short-term increases in MOR binding potential, in multiple pain and sensory processing regions including the cingulate (dorsal and subgenual), insula, caudate, thalamus, and amygdala. Acupuncture therapy also evoked long-term increases in MOR binding potential in some of the same structures including the cingulate (dorsal and perigenual), caudate, and amygdala. These short- and long-term effects were absent in the sham group where small reductions were observed, an effect more consistent with previous placebo PET studies. Long-term increases in MOR BP following TA were also associated with greater reductions in clinical pain. These findings suggest that divergent MOR processes may mediate clinically relevant analgesic effects for acupuncture and sham acupuncture. Show more