This story of a clinical trial of a generations-old cough and congestion remedy hits almost all the key points that we would expect of a report on even the most aggressive intervention for a life-threatening condition. Where it falls short is in describing the differences in symptom improvement reported by the groups given VapoRub, petroleum jelly or no treatment. Parents were asked to check boxes on a seven-point scale that went from 1=“not at all” through 4=”moderate” to 7=”very much or very severe.” By using a seven-point scale, instead of a three-point or five-point scale, the trial increased the chances of finding a statistically significant difference, while also increasing the likelihood that the difference would be so slight as to be meaningless. Moreover, in an industry-sponsored trial of which the lead author is a paid consultant skepticism is warranted. When the symptom scale used might detect clinically insignificant differences, and when several key aspects of study design are weak, the consumer should take VapoRub with a grain of salt.
The survey questions are available in the journal article posted online at http://pediatrics.aappublications.org/cgi/reprint/peds.2010-1601v1
Just because something is statistically significant does not always mean that people can sense a real difference. The big question left unanswered here is whether a one-point shift on a seven-point scale is meaningful.
One could say that the cost of VapoRub is not an important factor, but given how easy it would be to note the price of VapoRub, especially for the amount used in the study, we think the story should have included it.
The story does not tell readers how much of a difference there was between the treatment groups. The parents did report improvements, but readers can’t tell from this story just how much. The story would have been better if it pointed out that the parents were asked to rate symptoms on a seven-point scale. For instance, the effect on sleep ranged from 1 or “not at all much” to 7 or “very much” and the VapoRub on average nudged the symptoms just one point more than the petroleum jelly. What does it mean to feel one point better on this scale? The vague description of the relative improvement might lead readers to believe the differences were dramatic.
The story reports that almost half of the children who were treated with VapoRub reported side effects including skin irritation or a burning sensation, while none of the children in the other groups reported any side effects.
The story briefly describes that the trial had three arms (VapoRub, petroleum jelly, no treatment) and that parents told investigators about their children’s symptoms. But the story failed to report key aspects of the experiment that raise questions about its conclusions.Although parents were instructed to put VapoRub on their upper lips before opening the treatment container (that had VapoRub or petroleum jelly for their child) in order to attempt to mask the treatment, the researchers wrote that the masking effort largely failed. Almost 9 out of 10 parents were able to correctly guess whether their child was treated with VapoRub or petroleum jelly, so the parents’ beliefs about which treatment would be more effective could have influenced their survey responses. For unexplained (and unreported) reasons, the children who got petroleum jelly rubs took more acetaminophen pain reliever, which could suggest that there was some difference in their illnesses. While the story reports that there were differences in responses about sleep, the story does not tell readers that this single question accounted for most of the difference between the treatment groups, indicating that VapoRub may not be superior. The story also does not address the definition of “improvement” used in the statistical analysis, which may be sliced so fine as to be virtually meangingless.
The story accurately describes the children in the study as having “symptoms like cough, congestion, runny nose and restless sleep that lasted seven days or more.”
The story does include a comment from an independent pediatrician, and the story notes that she works for CNN. It also points out that funding for the trial came from the company that sells VapoRub and that the lead researcher is an advisor to the company.
The story points out that there have been growing concerns about other over-the-counter cold remedies for children. It also reports that the children who were not given any treatment also felt better the next day.
The availability of VapoRub is well known.
Although, there’s nothing new about VapoRub, the story does point out that the product claims have not been tested in this way before.
The story does not appear to rely on a news release.