Homoeopathy versus placebo in perennial allergic rhinitis

British Medical Journal, Jan 20, 2001 by Barry Miller, Brian J Lipworth, Michael Emmans Dean, Jurgen Windeler, H Morrow Brown, Morag A Taylor, David Reilly, Robert H Llewellyn-Jones, Charles McSharry, Tom C Aitchison

Statistics in study were flawed

EDITOR--Taylor et al come to the conclusion that their study of homoeopathy versus placebo in perennial allergic rhinitis "has failed to confirm our original hypothesis that homeopathy is a placebo."[1] Unfortunately, the statistics do not prove that.

The basis for the study was a prestudy power calculation that required 120 patients to prove the hypothesis with a 5% significance and an 80% power.[2] In fact, the authors only recruited 51 patients but analysed the results as if they had the required number. Their only conclusion was that they did not have enough data to make a conclusion.

If we accept the availability of only 51 patients at the outset, what are the relevant calculations? The power calculation is only 43%, and to maintain the power calculation at 80% the P value becomes 34%. The only conclusion is that the trial is not able to prove anything.

Barry Miller consultant anaesthetist Royal Oldham Hospital, Oldham OL1 2JH barry.miller@bigfoot.com

Competing interests: None declared.

[1] Taylor MA, Reilly D, Llewellyn-Jones RH. McSharry C, Aitchison TC. Randomised controlled trial of homoeopathy versus placebo in perennial allergic rhinitis with overview of four trial series [with commentary by T Lancaster, A Vickers]. BMJ 2000;321:471-6. (19-26 August.)

[2] Reilly DT, Taylor MA, McSharry C, Aitchison T. Is homoeopathy a placebo response? Controlled trial of homoeopathic potency, with pollen in hayfever as model. Lancet 1986;ii:881-6.

Study shows dissociation between objective and subjective responses to homoeopathy in allergic rhinitis

EDITOR--Taylor et al show the apparent dissociation between objective responses to homoeopathy (domiciliary nasal peak flow) and subjective responses (nasal symptoms) after four weeks in 50 patients with allergic rhinitis.[1] Few randomised controlled studies have measured domiciliary peak nasal inspiratory flow rate in allergic rhinitis, which makes these results all the more intriguing.

In one of those studies, of 38 patients with allergic rhinitis, nasal symptom scores showed significant (P [is less than] 0.01) correlations with morning and evening domiciliary nasal peak flow after four weeks of treatment.[2] The mean overall improvement in domiciliary nasal peak flow was 25 1/min in response to four weeks of antihistamine, which is comparable to the magnitude of the homoeopathy peak flow response (20 1/min).

Perhaps a longer period of homoeopathy or a different dose might have resulted in a subjective treatment response in patients with allergic rhinitis. Moreover, we need to know how homoeopathy compares to conventional drug treatments such as intranasal corticosteroids and antihistamines, given their proved long term efficacy on symptoms in allergic rhinitis.[3]

Brian J Lipworth professor of allergy and respiratory medicine Asthma and Allergy Research Group, Department of Clinical Pharmacology, Ninewells Hospital, Dundee DD1 9SY b.j.lipworth@dundee.ac.uk

Competing interests: The Asthma and Allergy Research Group has received funding from Aventis, AstraZeneca, Schering Plough, and GlaxoWellcome, which make intranasal corticosteroids and antihistamines.

[1] Taylor MA, Reilly D, Llewellyn-Jones RH, McSharry C, Aitchison TC. Randomised controlled trial of homoeopathy versus placebo in perennial allergic rhinitis with overview of four trial series [with commentary by T Lancaster, A Vickers]. BMJ 2000;321:471-6. (19-26 August.)

[2] Wilson A, Dempsey OJ, Sims EJ, Coutie WJR, Paterson MC, Lipworth BJ. Evaluation of treatment response in patients with seasonal allergic rhinitis using domiciliary nasal peak inspiratory flow. Clin Exper Allergy 2000;30:833-8.

[3] Weiner JM, Abramson MJ, Puy RM. Intranasal corticosteroids versus oral [H.sub.1] receptor antagonists in allergic rhinitis: systematic review of randomised controlled trials. BMJ 1998;17:1624-9.

Study shows double standards in evaluation of homoeopathy

EDITOR--The appearance of yet another high quality randomised trial in allergy raises the important question of whether homoeopathy should be treated any differently from conventional treatments in healthcare systems that are ostensibly evidence based.[1] It also brings to mind an example of the unforeseen way that double standards can rebound on those who refuse to accept any positive results for homoeopathy.

The homoeopathy meta-analysis by Linde et al was generally positive and also found a positive result in a subgroup of the most formally rigorous trials--those with quality scores [is greater than or equal to] 70%.[2] More recently, Juni et al compared 25 quality scales, including Linde et al's, by using them to rate a sample of 17 trials of low molecular weight heparin or standard heparin in the prevention of deep vein thrombosis during surgery.[3] Trials rated as high quality with Linde et al's scale showed greater benefit from low molecular weight heparin, reversing the findings of the original meta-analysis from which the sample of 17 heparin trials was taken.