Drs. Patrick and Hickner respond:
We thank Dr. Brown for providing useful information on the composition of the products made by Nature’s Way, noting that Umcka ColdCare “original” formula, an alcohol-based extract, is identical to the preparation used in the study. In addition, the excerpt from the study of the pharmacology of Pelargonium sidoides, which he summarizes, appears to further allay concerns that there might be adverse effects from the coumarin compounds in terms of increase in coagulation parameters or interaction with warfarin.
Dr. Weldy expresses concern that without knowing the composition of the placebo preparation, there may be other factors at play, especially the possibility that alcohol may be responsible for the outcomes rather than the Pelargonium.
We believe that it is highly unlikely that alcohol in the preparation is solely responsible for the superiority of the intervention over placebo. We noted that the placebo preparation was matched for color, smell, taste, and viscosity. It is true that no information was given as to the chemical composition of the placebo preparation, especially in terms of alcohol content. However, the dose is 30 drops (1.5 mL), which contains 12% alcohol by volume according to the manufacturer’s web site. This translates to approximately 0.18 mL alcohol in each dose (3.6 drops)—a very small amount. We agree, however, that it would be important for the authors to make explicit the similarities and differences between the 2 preparations.
Dr. Weldy notes that there appears to be minimal difference between intervention and placebo at 10 days, which he interprets as indicating that the intervention only masks symptoms at 5 days and has no overall impact on shortening duration of symptoms. The primary and secondary objectives of the study were focused on symptom severity, which we view to be an important patient-oriented outcome, especially because patients purchase medicines for symptom relief. At 5 days, this difference is impressive, and at 10 days, the intervention remains superior, although the difference in scores is certainly narrower.
Further, according to the study results: “On day 10, the rate of patients with clinical cure was significantly higher in the treatment group (Cold Intensity Score [CIS]=0 points: 63.5%; CIS ≤1 symptom: 78.8%) than in the placebo group (CIS=0 points: 11.8%; CIS ≤1 symptom: 31.4%; P<.0001 each).”
More than double the number of participants receiving the study preparation experienced complete or nearly complete symptom relief at day 10 than participants receiving placebo. We agree with Dr. Weldy in his assessment that it would be interesting to compare Pelargonium sidoides with “usual care,” ie, supportive treatment, with other over-the-counter remedies in common use by our patients.
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Gail Patrick, MD, MPP
John Hickner, MD, MSc
Department of Family Medicine,
University of Chicago