Is homeopathy effective for allergic rhinitis? Mathie et al think so; I disagree

As the data suggesting that homeopathy is effective for improving health is – to put it mildly – less than convincing, a frantic search is currently on amongst homeopaths and their followers to identify a specific condition for which the evidence is stronger than for all conditions pooled into one big analysis. If they could show that it works for just one disease, they could celebrate this finding and henceforth use it for refuting doubters stating that highly diluted homeopathic remedies are pure placebos. One such condition is allergic rhinitis; there have been several trials suggesting that homeopathy might be effective for it, and therefore it is only logical that homeopathy-promoters want to summarise these data in order to silence sceptics once and for all.

A new paper ought to be seen in this vein. It is systematic review by the Mathie group with the stated aim “to evaluate the efficacy and effectiveness of homeopathic intervention in the treatment of seasonal or perennial allergic rhinitis (AR).”

Randomized controlled trials evaluating all forms of homeopathic treatment for AR were included in a systematic review (SR) of studies published up to and including December 2015. Two authors independently screened potential studies, extracted data, and assessed risk of bias. Primary outcomes included symptom improvement and total quality-of-life score. Treatment effect size was quantified as mean difference (continuous data), or by risk ratio (RR) and odds ratio (dichotomous data), with 95% confidence intervals (CI). Meta-analysis was performed after assessing heterogeneity and risk of bias.

Eleven studies were eligible for SR. All trials were placebo-controlled except one. Six trials used the treatment approach known as isopathy, but they were unsuitable for meta-analysis due to problems of heterogeneity and data extraction. The overall standard of methods and reporting was poor: 8/11 trials were assessed as “high risk of bias”; only one trial, on isopathy for seasonal AR, possessed reliable evidence. Three trials of variable quality (all using Galphimia glauca for seasonal AR) were included in the meta-analysis: nasal symptom relief at 2 and 4 weeks (RR = 1.48 [95% CI 1.24-1.77] and 1.27 [95% CI 1.10-1.46], respectively) favoured homeopathy compared with placebo; ocular symptom relief at 2 and 4 weeks also favoured homeopathy (RR = 1.55 [95% CI 1.33-1.80] and 1.37 [95% CI 1.21-1.56], respectively). The single trial with reliable evidence had a small positive treatment effect without statistical significance. A homeopathic and a conventional nasal spray produced equivalent improvements in nasal and ocular symptoms.

The authors concluded that the low or uncertain overall quality of the evidence warrants caution in drawing firm conclusions about intervention effects. Use of either Galphimia glauca or a homeopathic nasal spray may have small beneficial effects on the nasal and ocular symptoms of AR. The efficacy of isopathic treatment of AR is unclear.

Extracts of Galphimia glauca (GG) have been used traditionally in South America for the treatment of allergic conditions, with some reports suggesting effectiveness. A 1997 meta-analysis of 11 clinical trials (most of them of very poor quality) of homeopathic GG suggested this therapy to be effective in the treatment of AR. In 2011, I published a review (FACT 2011, 16 200-203) focussed exclusively on the remarkable set of RCTs of homeopathic Galphimia glauca (GG). My conclusions were as follows: three of the four currently available placebo-controlled RCTs of homeopathic GG suggest this therapy is an effective symptomatic treatment for hay fever. There are, however, important caveats. Most essentially, independent replication would be required before GG can be considered for the routine treatment of hay fever. Since then, no new studies have emerged.

I am citing this for two main reasons:

• There is nothing homeopathic about the principle of using GG for allergic conditions; according to homeopathic theory GG extracts would need to cause allergies for GG to have potential as a homeopathic allergy remedy. Arguably, the GG trials should therefore have been excluded from this meta-analysis for not following the homeopathic principal of ‘like cures like’.
• All the RCTs of GG were done by the same German research group. There is not a single independent replication of their findings!

Seen from this perspective, the conclusion by Mathie et al, that the use of either Galphimia glauca … may have small beneficial effects on the nasal and ocular symptoms of AR, seems more than a little over-optimistic.