The clinical research literature in homeopathy is more positive than Ben Goldacre prefers to admit in his article “Benefits and risks of homoeopathy”, published in The Lancet on 16 November [1]. Goldacre claims “Five large meta-analyses of homoeopathy trials have been done. All have had the same result: after excluding methodologically inadequate trials and accounting for publication bias, homoeopathy produced no statistically significant benefit over placebo.” However, a more complete and unbiased assessment of the research evidence gives a very different perspective:

Three of the 5 meta-analyses that Goldacre cites did not reach the negative conclusion he implies, while the other 2 reports have limited interpretation. The first paper assessed 105 trials, 81 of them positive [2]. The authors concluded: "the evidence of clinical trials is positive but not sufficient to draw definite conclusions". The reviews for the European Commission concluded that homeopathy was more effective than placebo (P < 0.001) [3,4] though “the strength of this evidence is low because of the low methodological quality of the trials” (P = 0.082 for the highest quality sub-group of just 5 trials) [4]. The fourth analysis focused on trials of individualised homeopathy only, and thus did not represent the entire research evidence [5]. The most recent review narrowed its analysis to just 8 homeopathy trials compared with 6 in conventional medicine [6]; the negative findings were strongly affected by one particular Arnica trial [7].

Most importantly, Goldacre failed to cite one of the largest meta-analyses, which showed homeopathy can produce significant benefit over placebo. Published in The Lancet 10 years ago, Linde and colleagues analysed 89 trials and found a mean odds ratio of 2.45 (95% confidence interval, 2.05–2.93), in favour of homeopathy [8]. When considering just those trials of “high quality” and after correcting for publication bias, the findings actually remained statistically significant. The main conclusion was that the results “were not compatible with the hypothesis that the effects of homoeopathy are completely due to placebo”. In further analysis, the authors clarified that higher quality trials were less likely to be positive than those of lower quality, though the difference from placebo remained statistically significant until analysis was restricted to just five trials [9]. There was insufficient volume of evidence to enable conclusions to be drawn about the efficacy of homeopathy for any specific medical condition.

Moreover, Goldacre chooses not to report findings of systematic reviews that did in fact focus on research in particular medical conditions. Seven of 17 such reports to date have been positive for homeopathy: childhood diarrhoea [10]; influenza [11]; post-operative ileus [12]; seasonal allergic rhinitis [13,14,15]; vertigo [16]. Eight of the other 10 reviews were non-conclusive [17-24]; 2 were negative [25,26].

The above is not “cherry-picking positive studies”, as Goldacre views homeopaths’ approach to the research literature, but a frank summary of the evidence available in peer-reviewed publications. It is presented in the interests of a “clear and open discussion” that he rightly advocates.

Robert T Mathie Research Development Adviser, Faculty of Homeopathy

References:

1. Goldacre B. Benefits and risks of homoeopathy. Lancet 2007; 370: 1672–3.

2. Kleijnen J, Knipschild P, ter Riet G. Clinical trials of homoeopathy. BMJ 1991; 302: 316–23.

3. Boissel JP, Cucherat M, Haugh M, Gauthier E. Critical literature review on the effectiveness of homoeopathy: overview of data from homoeopathic medicine trials. Brussels, Belgium: Homoeopathic Medicine Research Group. Report to the European Commission. 1996: 195–210.

4. Cucherat M, Haugh MC, Gooch M, Boissel JP. Evidence of clinical efficacy of homeopathy – A meta-analysis of clinical trials. Eur J Clin Pharmacol 2000; 56: 27–33.

5. Linde K, Melchart D. Randomized controlled trials of individualized homeopathy – A state-of-the-art review. J Altern Complement Med 1998; 4: 371–88.

6. Shang A, Huwiler-Muntener K, Nartey L, et al. Are the clinical effects of homoeopathy placebo effects? Comparative study of placebo-controlled trials of homoeopathy and allopathy. Lancet 2005; 366: 726–32.

7. Lüdtke R, Rutten ALB. What a difference a trial makes! Focus Altern Complement Ther 2006; 11(suppl 1): 28–9.

8. Linde K, Clausius N, Ramirez G, et al. Are the clinical effects of homoeopathy placebo effects? A meta-analysis of placebo-controlled trials. Lancet 1997; 350: 834–43.

9. Linde K, Scholz M, Ramirez G, et al. Impact of study quality on outcome in placebo controlled trials of homeopathy. J Clin Epidemiol 1999; 52: 631–6.

10. Jacobs J, Jonas WB, Jimenez-Perez M, Crothers D. Homeopathy for childhood diarrhea: combined results and metaanalysis from three randomized, controlled clinical trials. Pediatr Infect Dis J 2003; 22: 229–34.

11. Vickers A, Smith C. Homoeopathic Oscillococcinum for preventing and treating influenza and influenza-like syndromes (Cochrane review). In: The Cochrane Library. Chichester, UK: John Wiley & Sons, Ltd. 2006: CD001957.

12. Barnes J, Resch K-L, Ernst E. Homeopathy for postoperative ileus? A meta-analysis. J Clin Gastroenterol 1997; 25: 628–33.

13. Wiesenauer M, Lüdtke R. A meta-analysis of the homeopathic treatment of pollinosis with Galphimia glauca. Forsch Komplementärmed Klass Naturheilkd 1996; 3: 230–6.

14. Taylor MA, Reilly D, Llewellyn-Jones RH, et al. Randomised controlled trials of homoeopathy versus placebo in perennial allergic rhinitis with overview of four trial series. BMJ 2000; 321: 471–6.

15. Bellavite P, Ortolani R, Pontarollo F, et al. Immunology and homeopathy. 4. Clinical studies – Part 2. Evid Based Complement Alternat Med 2006; 3: 397–409.

16. Schneider B, Klein P, Weiser M. Treatment of vertigo with a homeopathic complex remedy compared with usual treatments: a meta-analysis of clinical trials. Arzneimittelforschung 2005; 55: 23–9.

17. Pilkington K, Kirkwood G, Rampes H, et al. Homeopathy for anxiety and anxiety disorders: A systematic review of the research. Homeopathy 2006; 95: 151–62.

18. McCarney RW, Linde K, Lasserson TJ. Homeopathy for chronic asthma (Cochrane Review). In: The Cochrane Library. Chichester, UK: John Wiley & Sons, Ltd. 2004: CD000353.

19. McCarney R, Warner J, Fisher P, van Haselen R. Homeopathy for dementia (Cochrane Review). In: The Cochrane Library. Chichester, UK: John Wiley & Sons, Ltd. 2004: CD003803.

20. Pilkington K, Kirkwood G, Rampes H, et al. Homeopathy for depression: a systematic review of the research evidence. Homeopathy 2005; 94: 153–63.

21. Owen JM, Green BN. Homeopathic treatment of headaches: A systematic review of the literature. J Chiropractic Med 2004; 3: 45–52.

22. Ullman D. Controlled clinical trials evaluating the homeopathic treatment of people with human immunodeficiency virus or acquired immune deficiency syndrome. J Altern Complement Med 2003; 9: 133–41.

23. Smith CA. Homoeopathy for induction of labour (Cochrane Review). In: The Cochrane Library. Chichester, UK: John Wiley & Sons, Ltd. 2004: CD003399.

24. Long L, Ernst E. Homeopathic remedies for the treatment of osteoarthritis: a systematic review. Br Hom J 2001; 90: 37–43.

25. Ernst E, Barnes J. Are homoeopathic remedies effective for delayed-onset muscle soreness? – A systematic review of placebo-controlled trials. Perfusion (Nürnberg) 1998; 11: 4–8.

26. Ernst E. Homeopathic prophylaxis of headaches and migraine? A systematic review. J Pain Symptom Manage 1999; 18: 353–7.