A new study of homeopathic arnica suggests efficacy. How come?
Subjects scheduled for rhinoplasty surgery with nasal bone osteotomies by a single surgeon were prospectively randomized to receive either oral perioperative arnica or placebo in a double-blinded fashion. A commercially available preparation was used which contained 12 capsules: one 500 mg capsule with arnica 1M is given preoperatively on the morning of surgery and two more later that day after surgery. Thereafter, arnica was administered in the 12C potency three times daily for the next 3 days (“C” indicates a 100-fold serial dilution; and M, a 1000-fold dilution)
Ecchymosis was measured in digital “three-quarter”-view photographs at three postoperative time points. Each bruise was outlined with Adobe Photoshop and the extent was scaled to a standardized reference card. Cyan, magenta, yellow, black, and luminosity were analyzed in the bruised and control areas to calculate change in intensity.
Compared with 13 subjects receiving placebo, 9 taking arnica had 16.2%, 32.9%, and 20.4% less extent on postoperative days 2/3, 7, and 9/10, a statistically significant difference on day 7. Color change initially showed 13.1% increase in intensity with arnica, but 10.9% and 36.3% decreases on days 7 and 9/10, a statistically significant difference on day 9/10. One subject experienced mild itching and rash with the study drug that resolved during the study period.
The authors concluded that Arnica montana seems to accelerate postoperative healing, with quicker resolution of the extent and the intensity of ecchymosis after osteotomies in rhinoplasty surgery, which may dramatically affect patient satisfaction.
Why are the results positive? Pervious systematic reviews confirm that homeopathic arnica is a pure placebo. First, I thought the answer lies in the 1M potency. It could well still contain active molecules. But then I realised that the answer is much more simple: if we apply the conventional level of statistical significance, there are no statistically significant differences to placebo at all! I had not noticed the little sentence by the authors: a P value of 0.1 was set as a meaningful difference with statistical significance. In fact, none of the effects called significant by the authors pass the conventionally used probability level of 5%.
So, what so the results of this new study truly mean? In my view, they show what was known all along: HOMEOPATHIC REMEDIES ARE PLACEBOS.