Acupuncture for Fibromyalgia
By Nassim Assefi, MD
In one peer-reviewed study, at least 22% of patients with fibromyalgia (FM) had tried acupuncture in the past year.1 The National Institutes of Health Consensus Development Statement on Acupuncture states: "...musculoskeletal conditions such as fibro-myalgia, myofascial pain, and epicondylitis, are conditions for which acupuncture may be beneficial."2
Although scientific studies are provocative, and acupuncture is widely regarded by the public as effective in alleviating chronic pain, its potential benefit in chronic conditions like FM is largely unknown.
Definition and Symptoms
Fibromyalgia is a disorder of unknown etiology that is characterized by diffuse musculoskeletal pain and a panoply of other chronic symptoms. In 1990, the American College of Rheumatology established the diagnostic criteria for FM: diffuse musculoskeletal pain for at least three months and the presence of at least 11 of 18 tender points on physical examination (see Figure, below).3
Although not included in the case definition, many FM patients report symptoms such as sleep disturbance, fatigue, psychological distress, chronic headaches, irritable bowel, and interstitial cysti-tis.4-6 Routine laboratory testing generally is normal.
Some sources estimate that 2% of the general population, or 6 million Americans, suffer from FM, making it the second most common rheumatologic condition after osteoarthritis. In both community and clinic settings, 85% of patients are women and many are middle-aged.5,6
Most randomized, controlled trials of allopathic interventions have failed to demonstrate a sustained effect, although antidepressants (especially tricyclics), aerobic exercise, and cognitive behavioral therapy may provide some benefit. Thus, it is not surprising that 60-90% of patients with FM use complementary and alternative medicine (CAM).7,8
Mechanism of Action
Acupuncture has been used as a therapeutic intervention for more than 2,500 years in China, and since its re-introduction in the United States in the early 1970s, it has become one of the most widely used and accepted forms of CAM.
Western biomedical theory cannot predict the effects of needling at acupoints; furthermore, no unique anatomic structures corresponding to such points have been found.9 Of the structures examined, free nerve endings have the highest correspondence to acupuncture points.10 Of relevance to FM, a large number of acupuncture points coincide with trigger points.11
A central mechanism of action has been suggested by a small study using single photon emission computed tomography that demonstrated baseline asymmetry and lower count ratios in the thalamus of pain patients compared to healthy volunteers.12 Following acupuncture, the asymmetry resolved and most patients had substantially increased uptake of radiotracer in the brain stem.
Despite the absence of well-recognized anatomical sites of action, studies in animals and humans clearly have shown that acupuncture results in measurable biological changes, including release of endorphins and monoamines. Acupuncture analgesia is blocked by opioid antagonists such as naloxone,13 and injections of antibodies against enkephalin, beta-endorphin, and dynorphin into analgesic regions of the central nervous system, but not elsewhere, block acupuncture analgesia.14,15
Literature searches of PubMed, Cochrane registry, CINDAHL, Biosis, Embase, and Alternative Medicine Alert, supplemented by conference abstracts, citations, and letters, using "acupuncture" and "fibromyalgia" or "fibrositis" or "fibromyositis" as key words revealed eight relevant studies.
Although all of these studies consistently have shown beneficial effects of acupuncture for fibromyalgia symptoms, the majority have been small, poorly controlled, non-randomized trials.
Two excellently designed randomized, controlled trials (RCTs) are the exception. The first is a three-week RCT of electroacupuncture in 70 patients.16 Pain threshold improved significantly by 70% in the active intervention group compared with 4% in the sham group. In fact, seven of the eight outcome measures (pain threshold, number of analgesics used in last week, subjective and regional pain, sleep, morning stiffness, and patient- and physician-rated improvement) showed significant improvement with treatment; no changes in any of these parameters were encountered in the control patients. Furthermore, for five of the eight outcomes, there also were significant differences between the treated and untreated groups.
The second study randomized 60 patients to weekly acupuncture, weekly sham acupuncture, or usual care.17 All patients received 25 mg of amitryptyline at bedtime and treatment lasted 16 weeks. Validated pain and depression scales were significantly different between the acupuncture group and the two control groups; no improvement occurred in the sham acupuncture and usual care groups.
Limitations of the above studies include the following: 1) there is considerable controversy over electroacupuncture and whether it is equivalent to conventional acupuncture (some practitioners believe that the former provides primarily short-term analgesia, while the latter may afford longer-term pain relief); 2) in neither study were measures used to assess if patients actually were blind to treatment; 3) the first study did not include functional or psychological measures, and the second study did not use any objective measures (such as dolorimetry or blinded assessment); and 4) there was no long-term follow-up on either study.
Long-term follow-up is crucial because FM is a chronic illness with symptoms that wax and wane over time and the analgesic effects of acupuncture may be transient, especially with brief treatment protocols (e.g., four weeks or less).
Virtually all clinical trials of acupuncture have been plagued by serious methodological flaws (see Table, below).
In addition, there are diverse schools and styles of acupuncture that likely vary in their efficacy for certain conditions; hence no single trial can claim to be representative of all types of acupuncture.
Perhaps the methodological issue posing the greatest difficulty in assessing the potential utility of acupuncture is the choice of controls. Invasive sham acupuncture consists of the insertion of needles at locations on the body supposedly ineffective for the condition being treated. However, there are no standards to guide researchers in identifying appropriate sham point locations, or depth, direction, or duration of needle insertion.
The use of sham controls depends heavily on traditional acupuncture theory that posits that acupuncture should be effective only if condition-specific classical points are used. Non-invasive sham acupuncture, which attempts to mimic an inert placebo, uses non-insertive needling devices to simulate the sensation of acupuncture. However, patients must be blindfolded, acupuncture naïve, and assessed for expectation and credibility of treatment group in order to maximize successful blinding.
Methodological challenges of acupuncture studies18,19
• Appropriate and adequate treatment (a sufficient number of points stimulated per treatment, adequate frequency and duration, adding extra stimulation of acupoints using electroacupuncture or moxibustion, and fixed regimens stimulating predetermined acu- points vs. individualized treatments);
• Appropriate comparison groups;
• Blinding of patients and practitioners (although the latter of which is impossible, but assessors blinded to treatment group can be used for objective measures);
• Adequate sample sizes;
• Adequate assessment of outcomes (validated subjective and objective measures); and
• Adequate duration of trial and follow-up.
Overall, acupuncture is extremely safe and major injuries are uncommon. A study compiling Medline-reported acupuncture complications between 1981 and 1994 revealed adverse events in only 193 patients worldwide and three reported deaths.20 Hepatitis was the most common infectious complication, reported in 100 of the 193 patients. This occurred when sterilization of the acupuncture needles had not been performed properly. Pneumothorax was the second most common complication, reported in 23 patients. Patients with chronic obstructive pulmonary disease were at highest risk. Other minor complications included the "acupuncture faint" (a vasovagal reaction), bleeding, localized skin infection, and localized pain.
Most of the serious complications can be avoided in the United States, where sterile, disposable acupuncture needles are used and needle penetration tends to be less deep than in classical Chinese acupuncture.
Two well-designed but small RCTs of acupuncture for the treatment of FM provide promise of a beneficial therapeutic intervention in a condition that currently has few effective treatment options and is associated with substantial disability.
Although the exact mechanism of acupuncture analgesia is not understood, numerous studies demonstrate shifts in neurohormonal concentrations following acupuncture that make chronic pain relief biologically plausible. The effects of invasive sham acupuncture and placebo acupuncture, while conceived of as controls for true acupuncture, are largely unknown. Nevertheless, acupuncture has few risks other than the out-of-pocket expenses incurred by patients whose insurance plans may not cover acupuncture treatments.
Many questions will be answered by two ongoing National Center for Complementary and Alternative Medicine-sponsored RCTs that are larger than previous studies and have addressed many of the methodological flaws of the past; results are due by 2003.
Although there is no consensus regarding optimal treatment for FM, acupuncture should be considered in conjunction with antidepressants, aerobic exercise, and cognitive behavioral therapy. However, specific recommendations such as type of acupuncture employed, the duration and frequency of treatment, and the degree of acupoint stimulation cannot be made definitively.
Dr. Assefi is Attending (Clinician-Teacher), Departments of Medicine and Obstetrics/Gynecology, Complementary and Alternative Medicine Liaison, School of Medicine, University of Washington in Seattle.
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