Letters
Acupuncture, Fools and Horses
 
 

To the Editor:

Today, many if not most pain clinics use acupuncture as an adjunctive form of analgesia. Why? Quite obviously because it is perceived as effective in many cases. But why then are the conclusions of systematic reviews so disappointingly unconvincing? "The efficacy of acupuncture in the treatment of chronic pain remains doubtful."1 The effectiveness of acupuncture has still not been conclusively demonstrated."2 It would be easy to provide additional quotes.

When, in the 1970s, acupuncture became popular in the West, many reports suggested efficacy. Later, when more rigorous trials tested the hypothesis, some studies implied that acupuncture is not significantly more effi­cient than sham needling. As well, systematic reviews on the efficacy of acupuncture for pain relief failed to give conclusive answers. In other areas of clinical acupuncture research, this course of events repeated itself: smoking cessation,3 weight loss,4 and osteoarthritis.5

Enthusiasts usually counter that acupuncture has been proved because it elevates opioid peptides and other neurotransmitter levels. True, a variety of ­plausible mechanisms exist to explain acupuncture works (see, for example, Han and Terenius6). But are we not fools if we do not insist on hard evidence proving beyond reasonable doubt that it works clinically?

Some might argue that acupuncture works because trials on animals have proved it. The (somewhat muddled) notion is that animals are not prone to placebo responses. Let us look at the analogous sequence of' events when acupuncture was given to horses. Early pilot studies had suggested that it might help the pain of lameness.7 Nonrandomized trials apparently confirmed this notion.8 But one of the very few randomized clinical trials of acupuncture in animals showed that acupuncture?treated horses fared no better than untreated controls.9

How can we make sense of these data? One possible explanation is that we are being fooled by bias inherent in many trials. The most powerful source of bias is introduced through non-randomization9 Excluding it is likely to render analyses negative, leading to the conclusion that acupuncture is not convincingly associated with a specific therapeutic effect.

But still acupuncture works! Thousands of clinicians using it and millions of patients swearing by it would hardly accept that they were fundamentally wrong. The discrepancy may not be all that difficult to resolve. What if acupuncture worked (mostly) through a powerful nonspecific (placebo) effect? Would we then not expect that flawed trials often come out positive although rigorous studies are likely to be negative? Would we then not also expect that clinical experience is overwhelmingly positive whereas well?controlled trials are not? In fact, there are very good data from randomized sham?controlled trials to suggest that acupuncture's nonspecific effects are indeed impressive (for example, Ter Riet, et at.,1 Resch and Ernst,2 White and Rampes,3 and Ernst,4,5).

If' this is so, what should we conclude? Should we continue to rise acupuncture in pain clinics? After all, placebos can do much good and little harm.10 Maybe, but only fools would not consider two further points. Contrary to what is often claimed, acupuncture is not an entirely safe procedure.11 At the very least, we should investigate exactly how large the risks are and how they might be minimized. Furthermore, if we are dealing pre?dominantly with nonspecific effects, should we not systematically research these with a view toward maximizing12 these within and outside the world of' acupuncture? Fools and horses can afford to be shortsighted; physicians cannot.

Edzard Ernst, MD, Ph.D, FRCP (Edin) Department of Complementary Medicine Postgraduate Medical School
University of Exeter Exeter,
United Kingdom
 

References

1. Ter Riet G, Kleijnen J, Knipschild P. Acupuncture and chronic pain: a criterion based metaanalysis. J Clin Epidemiol

2. Resch KL, Ernst E. Wirksamkeitsnachweise komplcmentareer therapien. Fortschr Med 1995; 13:41?47.

3. White A, Rampes H. Acupuncture in smoking Cessation. Cochrane Database of Systematic Reviews, 1996.

4. Ernst E. Acupuncture/acupressure for weight reduction: a systematic review. Wien Min Wochenschr 1997;109:60?62.

5. Ernst E. Acupuncture as a symptomatic treatmcnt of osteoarthritis. Scand J Rheumatol (in press).

6. Han J, Tereniusus L. Neurochemical basis of acupuncture analgesia. Annu Rev Pharmacol Toxicol 1982?122: 192?220.

7. Degroot A, Bresler DE. Acupuncture: a pilot program in the horse. Proc Am Assoc Equine Pract 1973; 19:212?218.

8. Gideon L. Acupuncture, clinical trials in the horse. J Am Vet Med Assoc 1977;170:220?224.

9. Steiss JE, White NA, Bowen JM. Electro?acupuncture in the treatment of' chronic lameness in horses and ponies: a controlled clinical trial. Can J Vct Res 1989;53;239?243.

10. Ernst E, Hcrxheimer A. The power of' placebo. BMJ l996;.313:l569?l570.

11. Ernst E, White A. Acupuncture: safety first. BMJ 1997;314:1362.