Where's the Bias?

In July 1996, Annals published the results of a double-blind, randomized, controlled trial describing the effects of zinc lozenges on the symptoms of the common cold [1]. The lozenges, produced by the Quigley Corporation of Doylestown, Pennsylvania, seemed to reduce the duration of symptoms by about 40% compared with placebo, confirming the results of several previous studies but contrasting with the findings of others. As noted in the published article, the study was supported by funds from the researchers' institution; the Quigley Corporation supplied the active medication and the placebo.

In the cover letter that accompanied the manuscript, the authors told us that none of them had held any financial interest in Quigley before designing and conducting the study but that after the randomization code was broken and the results analyzed two of the authors, Dr. Macknin and Ms. Medendorp, had acquired stock in Quigley through private sale. Annals was therefore duly informed about a potential conflict of interest. In our judgment, the potential for bias from commercial influence was minimal because the financial link between the authors and the company occurred after the fact of the research; we therefore chose not to publish the authors' disclosure.

When the study appeared, neither the press nor the public took much notice of the results, although the value of Quigley stock increased slightly. With November, however, came a rapid drop in outdoor temperatures and an even faster increase in the price of Quigley stock, which triggered extensive coverage in the general press of both the conduct and publication of the study itself and of subsequent business developments [2-7]. Most of this coverage was accurate; some of it was misleading [8]. Despite the substantial “eyebrow raising” over the financial decision of Dr. Macknin and Ms. Medendorp, the scientific quality of …