Bret S. Stetka, MD


May 09, 2016

Editor's Note:
While on site at the 2016 American Academy of Neurology Annual Meeting, Medscape interviewed Tricia Ting, MD, associate professor in the Department of Neurology at the University of Maryland School of Medicine, about her new study exploring the influence of pill color on drug adherence.

Medscape: What were the objectives of your study, and can you also touch on the methods?

Dr Ting: Our intention at the outset was to choose a capsule color from a selection of commercially available colors for over-encapsulation in order to do a clinical trial. Drug adherence was a serious concern in a novel bioequivalence study that our group was running, in which epilepsy patients would be responsible for taking the study drug at home for weeks at a time before returning for intensive pharmacokinetic testing of their levels. The possibility that our choice of capsule color could evoke negative expectations and affect drug adherence in the trial caused us to pause and consider what color our patients might prefer—or, more importantly, not prefer.

We could not find an answer in the literature on preferred capsule color selection for clinical trial blinding, nor for color preference, that would necessarily apply to our population of patients in the United States or to those taking antiepileptic drugs for seizures. So we polled nearly 100 patients with epilepsy in a cross-sectional study at our outpatient neurology clinic. Patients were shown standard AA size capsules in five global colors (white, yellow, gray, caramel, maroon). We asked them to note any colors as "unacceptable" and also to rank-order their color preference for the five choices from "highly preferred" to "highly not preferred."

We looked for a statistically significant preference for at least one color and examined relative differences in rank order between colors for which there was a statistically significant preference. We then used multivariate regression analysis to determine whether color preference differences could be explained by sex, race, age, or number of medications.

Medscape: Can you summarize what you found?

Dr Ting: Of the five global colors surveyed, we found a statistically significant difference in preference for the colors white and yellow over gray, caramel, and maroon. We also found notably opposing opinions on the color maroon; some patients highly preferred it but others were strongly against it.

On the basis of the multivariate analysis, race was the only factor that explained the differential preferences toward maroon, with African Americans accounting for the majority of "highly not preferred" rankings for the color. We also saw a statistically significant difference of age for gray color preference, suggesting that as the age increases, the preference for gray decreases. However, due to the small study size, we interpret these specific associations between race, age, and color preference with caution.

As it turns out, we used our findings to select white capsules for blinding in our bioequivalence trial, which resulted in excellent patient retention, with nearly all enrolled patients completing, as well as exceptional adherence on the basis of the pharmacokinetic data results.


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