migraine
Lots of alternative therapies are advocated for migraine. Few of them are supported by good evidence. An exception could be the herbal remedy FEVERFEW.
This review is an update of a previously published review in the Cochrane Database of Systematic Reviews on ‘Feverfew for preventing migraine’. Feverfew (Tanacetum parthenium L.) extract is a herbal remedy, which has been used for preventing attacks of migraine. Our aim was to systematically review the evidence from double-blind, randomised, clinical trials (RCTs) assessing the clinical efficacy and safety of feverfew monopreparations versus placebo for preventing migraine.
For this updated version of the review we searched CENTRAL, MEDLINE, EMBASE and AMED to January 2015. We contacted manufacturers of feverfew and checked the bibliographies of identified articles for further trials.
We included randomised, placebo-controlled, double-blind trials assessing the efficacy of feverfew monopreparations for preventing migraine in migraine sufferers of any age. We included trials using clinical outcome measures, while we excluded trials focusing exclusively on physiological parameters. There were no restrictions regarding the language of publication.
We systematically extracted data on patients, interventions, methods, outcome measures, results and adverse events. We assessed risk of bias using the Cochrane ‘Risk of bias’ tool and evaluated methodological quality using the Oxford Quality Scale developed by Jadad and colleagues. Two review authors independently selected studies, assessed methodological quality and extracted data. We resolved disagreements concerning evaluation of individual trials through discussion.
We identified one new study for this update, resulting in a total of 6 trials (561 patients) meeting the inclusion criteria. Five of the 6 trials reported on the main outcome measure which was migraine frequency. Although 5 of the trials were generally of good methodological quality, all studies were either of unclear or high risk of bias with regards to sample size. Pooled analysis of the results was not possible due to the lack of common outcome measures and heterogeneity between studies in terms of participants, interventions and designs. The most recent trial added to this update was rigorous and larger (n = 218) than previous studies. It used a stable feverfew extract at a dose determined by a previous dose-finding trial. It reported that feverfew reduced migraine frequency by 1.9 attacks from 4.8 to 2.9 and placebo by 1.3 from to 4.8 to 3.5 per month. This difference in effect between feverfew and placebo was thus 0.6 attacks per month. For the secondary outcome measures such as intensity and duration of migraine attacks, incidence and severity of nausea and vomiting, and global assessment no statistically significant differences between feverfew and placebo were reported.
The results of previous trials were not convincing: three trials reporting positive effects of feverfew were all of small sample size (17 to 60 participants), while two rigorous trials (n = 50, 147) did not find significant differences between feverfew and placebo.
Only mild and transient adverse events of feverfew, most commonly gastrointestinal complaints and mouth ulcers, were reported in the included trials.
We concluded that, since the last version of this review, one larger rigorous study has been included, reporting a difference in effect between feverfew and placebo of 0.6 attacks per month. This adds some positive evidence to the mixed and inconclusive findings of the previous review. However, this constitutes low quality evidence, which needs to be confirmed in larger rigorous trials with stable feverfew extracts and clearly defined migraine populations before firm conclusions can be drawn. It appears from the data reviewed that feverfew is not associated with any major safety concerns.
So, good or bad news for migraine sufferers? I suppose it depends on whether you are an optimist or a pessimist. I would say that, considering the mostly bad news about alternative medicine for migraine, it is relative good news: patients who want to try something ‘natural’ could do so, particularly in view of the lack of serious risks.
“If ever there was a permanent cure for migraine, homeopathic medicines are the only one that can do this miracle. It may sound like an overstatement and quite quackerish, but it’s true. Long term treatment with homeopathy has an excellent cure for migraine headaches.” Statements like this can be found by the thousands on the internet, not just in relation to migraine but also about osteoarthritis. Both migraine and osteoarthritis are important domains for homeopathy, and most homeopaths would not doubt for a second that they can treat these conditions effectively. This is why it is so important to highlight the few sources which are not misleading consumers into making the wrong therapeutic decisions.
‘Healthcare Improvement Scotland’ (HCIS) have just published advice for patients suffering from migraine and osteoarthritis (the full document with all the evidence can be found here). I think it is worth having a close look and I therefore cite it in full:
Homeopathic remedies are prepared by repeated dilution and vigorous shaking of substances in water. Remedies are prepared from substances that in healthy people cause the signs and symptoms of the condition being treated. The more dilute the remedy is the more potent it becomes so that the most potent remedies are unlikely to contain any of the original substance.
People in Scotland have access to homeopathy through some GPs or a referral to homeopaths in the private sector, regional NHS clinics or the Centre for Integrative Care (CIC) (formerly Glasgow Homeopathic Hospital). Not all NHSScotland health boards provide funding for homeopathy; investment varies widely among those that do, and individual boards have begun to review funding for homeopathy services.
Clinical effectiveness
- Evidence of clinical effectiveness was reviewed from systematic reviews of four placebo controlled randomised trials of homeopathy for migraine published between 1991 and 1997; and systematic reviews of four active treatment controlled randomised trials of homeopathy for osteoarthritis published between 1983 and 2000. The quality of the evidence was low to moderate.
- Homeopathy for migraine has not been compared with active treatment in randomised controlled trials (RCTs). Of four RCTs comparing homeopathy with placebo, only one found homeopathy to be superior.
- Three RCTs in osteoarthritis comparing homeopathy with medicines for pain relief found either no difference between the interventions, or that analgesic treatment had a better effect than homeopathy. A further RCT comparing intra-articular injection of a homeopathic remedy with hyaluronic acid injections showed similar pain reduction in both groups.
Safety
- Published systematic reviews of homeopathy for migraine and osteoarthritis contain insufficient information to inform conclusions about safety.
Cost effectiveness
- No evidence on the cost effectiveness of homeopathy for migraine was identified; and the evidence from a single cost-minimisation analysis of one homeopathic preparation for osteoarthritis is not generalisable to the UK.
Context/conclusion
- Homeopathy for migraine has not been compared with standard care in RCTs and no evidence of cost effectiveness has been identified..
- There is insufficient evidence to determine whether or not homeopathic treatment for osteoarthritis is clinically effective compared with standard care, and no relevant evidence of cost effectiveness has been identified.
- The evidence does not support treating migraine or osteoarthritis with homeopathy.
Before the fans of homeopathy start shouting “THIS IS ALL RUBBISH AND DISREGARDS IMPORTANT EVIDENCE!!!”, I should mention that the top experts in homeopathy were asked to contribute their evidence and were unable to find any convincing data that would have changed this negative verdict. And it is important to point out that HCIS is a respected, independent organisation that issues statements based on thorough, unbiased reviews of the evidence.
As I reported a while ago, the Australian ‘NATIONAL HEALTH AND MEDICAL RESEARCH COUNCIL’ has assessed the effectiveness of homeopathy. The evaluation looks like the most comprehensive and most independent in the history of homeopathy. Its draft report concluded that “the evidence from research in humans does not show that homeopathy is effective for treating the range of health conditions considered.”
So, the HCIS is in excellent company and I have no doubt whatsoever that this new statement is correct – but I also have little doubt that homeopaths will dispute it.
