By David W. Ramey
Posted: Saturday, January 1, 2000
ARTICLES
Publication Date: January 1, 2000
The scientific investigations of homeopathy [see PfH, Vol. 11, No. 4, Homeopathy and Its Founder: Views of a British Researcher] that have been completed and published are sufficient for drawing reliable conclusions about this counterscientific approach to medicine. These studies have generated widely assorted positive, negative, and neutral conclusions. Therefore, it is not difficult, especially if one does not consider the quality of the evidence, to find published conclusions compatible with, or pervertible to, a particular bias. But parading pieces of evidence thus culled does the public little or no good.
Homeopathy has been the subject of at least 12 scientific reviews, including meta-analytic studies, published since the mid-1980s.
A sensible short-cut to taking on the question of whether homeopathy is effective is to examine all relevant published reports of meta-analytic studies (statistical studies of studies) and of other scientific reviews. This approach is not without drawbacks, however. In a meta-analytic study, for example, an explicit and straightforward conclusion may be based on the findings of weak (e.g., poorly designed) studies.
Homeopathy has been the subject of at least 12 scientific reviews, including meta-analytic studies, published since the mid-1980s. From reading the literature that proponents of homeopathy disseminate, one might well get the impression that the findings of these studies are somewhat open to interpretation, and that the basic question regarding the evidence amounts to: "Is the glass half empty, or half full?" But the findings are remarkably consistent:
* In a 1990 French review of 40 published randomized clinical trials of homeopathy, researchers found that most of the studies had had major methodological flaws and concluded: ". . . the results do not provide acceptable evidence that homeopathic treatments are effective."
* In a meta-analytic study of homeopathy in human medicine published in The British Medical Journal in 1991, investigators concluded: "At the moment the evidence of clinical trials is positive but not sufficient to draw definitive conclusions because most trials are of low methodological quality and because of the unknown role of publication bias. This indicates that there is a legitimate case for further evaluation of homeopathy, but only by means of well-performed trials."
* In a 1992 German review of homeopathy in human medicine, researchers concluded: ". . . The review of studies carried out according to current scientific criteria re-vealed—at best—a placebo effect of homeopathy. Until now there is no proven mechanism for the mode of action of homeopathy. Some-times so-called alternative medicine prevents effective curative measures. . . ."
* In a 1993 German review of homeopathy in veterinary medicine, researchers came to several conclusions: (a) "Doctor and veterinarian are similarly obligated to apply the therapeutic measure that prevailing opinions deem most effective. Where there is for particular definite illnesses a particularly effective and generally recognized treatment, in such cases the supporters of homeopathy may not disregard the better successes from their own differing direction." (b) "It is undisputed that homeopathy in the area of stronger potency can achieve effects pharmacologically and toxicologically; the superiority of homeopathy as a therapeutic measure in comparison with conventional therapy methods is at this point not verified. Moreover, the harmlessness of homeopathy in stronger potency is for the most part not verified." (c) "The effectiveness of homeopathy in middle and high potencies is up to now not verified. It is undisputed that with the help of homeopathy, not insignificant placebo effects can be achieved. In veterinary medicine, giving an animal an 'active' placebo and another a 'passive' can play a significant role and influence the owner."
Wynn even described a study in which the condition of sick animals had worsened as possible evidence of [homeopathy's] of a 'healing crisis.'
* Every standard homeopathic preparation is a serial agitated dilution (SAD)—that is, a result of the successive ad-mixture and agitation of a substance. In a 1994 review and meta-analytic study of SADs in experimental toxicology, investigators stated: "As with clinical studies, the overall quality of toxicology research using SAD preparations is low. The majority of studies either could not be reevaluated by the reviewers or were of such low quality that their likelihood of validity is doubtful. The number of methodologically sound, independently reproduced studies is too small to make any definitive conclusions regarding the effect of SAD preparations in toxicology."
* In a 1996 French review of homeopathy, researchers made the following statements. (a) "No one should ignore the role of nonspecific factors in therapeutic efficacy, such as the natural history of a given disease and the placebo effect. Indeed, these factors can be used to therapeutic advantage." (b) "As homeopathic treatments are generally used in conditions with variable outcome or showing spontaneous recovery (hence their placebo responsiveness), these treatments are widely considered to have an effect in some patients." (c) "How-ever, despite the large number of comparative trials carried out to date there is no evidence that homeopathy is any more effective than placebo therapy given in identical conditions." (d) "We believe that homeopathic preparations should not be used to treat serious diseases when other drugs are known to be both effective and safe." (e) "Pending further evidence, homeopathy remains a form of placebo therapy."
* Of their study published in The Lancet in 1997, investigators said: "The results of our meta-analysis are not compatible with the hypothesis that the clinical effects of homeopathy are completely due to placebo. However, we found insufficient evidence from these studies that homeopathy is clearly efficacious for any single clinical condition." They further stated: "Our study has no major implications for clinical practice because we found little evidence of effectiveness of any single homeopathic approach on any single clinical condition." In conclusion the researchers stated that more research on homeopathy was in order "providing it is rigorous and systematic."
(In a later issue, a critic of the study noted that the best of the trials in question had been distinctly less likely to generate a positive finding than had the trials as a whole, and another critic indicated that preferential nonpublication of relevant studies that had generated negative findings may have skewed the findings of the meta-analytic study.)
* In another meta-analytic study conducted in 1997, researchers examined the use of homeopathy for postoperative ileus, a condition characterized principally by surgical lack of peristalsis and measured by the delay between the close of a surgical procedure and the first post-op expulsion of flatus. The investigators concluded: "[Our analyses] do not provide evidence for the use of a particular homeopathic remedy or for a combination of remedies for postoperative ileus. Several drawbacks inherent in the original studies and in the methodology of meta-analysis preclude a firm conclusion." They also noted that the effect of homeopathic preparations of not more than 12c—i.e., preparations that might contain some of the basic substance—was significant, whereas that of homeopathic preparations of more than 12c was not.
* In a review of homeopathic treatment of animals published in 1998, S. G. Wynn recommended approaching homeopathy with an "open mind." As evidence of efficacy, she cited three studies in which some improvement had been directly observed, seven studies whose data were ambiguous, and six studies in which the animals' condition had worsened or had not changed. In several of these 16 studies, the subjects had been healthy to start with. Wynn even described a study in which the condition of sick animals had worsened as possible evidence of effectiveness through induction of a "healing crisis."
* In a 1998 review of the effects of homeopathic preparations based on the herb arnica, which are typically used to treat conditions due to physical trauma, researchers concluded: "The claim that homeopathic arnica is efficacious beyond a placebo effect is not supported by rigorous clinical trials."
* In a review published in November 1999 of the use of homeopathic "remedies" to prevent headaches, E. Ernst concluded that available trial data do not suggest that homeopathy is more effective than a placebo in the prevention of migraines or other headaches.
* In a meta-analytic study published in January 2000, it was found that a homeopathic preparation for preventing colds and the flu was ineffective.
Several rigorous trials of homeopathy in human medicine have been performed in recent years. According to these randomized, placebo-controlled, double-blind trials, homeopathic "remedies" are not effective:
* in the treatment of adenoid vegetations (abnormal glandular growths) in children,
* for controlling pain and infection after a total abdominal hysterectomy, and
* for preventing migraines.
Furthermore, none of the studies that have generated positive findings has been replicated with such findings, the methodological quality of these studies has been questionable, and the better studies of homeopathy have tended not to generate positive findings.
David W. Ramey, D.V.M., has been practicing equine medicine and surgery since 1983. He is the author of nine books on equine health, including A Consumer's Guide to Alternative Therapies in the Horse (Howell Bookhouse, 1999).
(From Priorities, Vol. 12, No. 1)
