Of the 10 attributes evaluated in the survey, total pills per day had a mean attribute importance score of 14 percent, followed by dosing frequency (13 percent), adverse events (12 percent), diet restrictions (11 percent), pill size (10 percent); number of refills (9 percent) number of insurance co-pays (9 percent), number of prescriptions (8 percent) number of medication bottles (8 percent) and the requirement of bedtime dosing (6 percent).
"In the past, studies have looked primarily at one or two factors related to adherence and measured their impact as single entities," said Valerie Stone, M.D., M.P.H., lead investigator, Associate Chief, General Medicine Unit, Department of Medicine, Massachusetts General Hospital; and Associate Professor of Medicine, Harvard Medical School, Boston. In the PASPORT survey, we used an adaptive conjoint methodology, sometimes called 'trade off' analysis, which reflects the reality of making HIV treatment decisions as patients consider various trade-offs to tailor a regimen that fits their lifestyles and preferences.
Dr. Stone presented the results of the survey at IDSA today.
Based on survey results, the preferred characteristics of a regimen would include two small pills dosed at the same time each day with no food requirements or restrictions, an ¡§acceptable¡¨ adverse event profile, and one prescription refilled monthly with one co-pay.
"The PASPORT Survey supports research documenting that multiple factors impact a patient¡¦s ability to follow a treatment plan exactly as prescribed," said Dr. Stone. Adherence is a complex problem, and over reliance on any single factor may, in fact, impede adherence for some patients, as our survey suggests. Multiple treatment characteristics and the interactions among them should be taken into consideration in tailoring a treatment regimen that may enhance adherence for the individual patient.
Despite a lack of data, it is a common assumption that QD dosing will improve adherence. Although QD dosing was deemed the most desirable dosing schedule by the individuals surveyed, actual QD regimens currently available were perceived as no more likely to improve adherence than a BID regimen consisting of one pill per dose when multiple attributes of HAART regimens were considered simultaneously. This seems to be in large part again, because patients seem to prefer low pill count over QD dosing as the most important attribute,¡¨ said Dr. Stone. Further, the survey found that QD regimens requiring more than two pills per day were less favorably rated than a BID regimen requiring a total of two pills per day.
The main findings related to dosing simplicity derived from the survey were:
- Total number of pills per day. Patients rated fewer pills higher and the fewest number of pills evaluated two the highest.
- Dosing frequency. Taking medication less often was rated higher by patients. Taking all drugs once a day at the same time was rated the highest.
- Adverse events. Although the differences in adverse events (AEs) among the regimens studied was not large, AEs ranked third in importance relative to other treatment characteristics considered in the survey. "This reinforces the importance of discussing potential side effects with patients, and taking steps to prevent them or manage them aggressively should they occur," Dr. Stone said.
- Dietary restrictions. The requirement that pills be taken on an empty stomach was viewed as a greater barrier to adherence than other dietary restrictions, according to survey responses. Having no food restrictions or requirements was rated the highest.
- Number of prescriptions/copays. Patients rated fewer number of prescriptions/co-pays higher, with one prescription filled monthly with one co-pay being rated the highest.
In addition to assessing the relative impact on anticipated adherence of dosing characteristics, the survey participants also evaluated seven triple-HAART regimens frequently prescribed for patients with HIV, including three regimens comprising QD medications. The regimens were evaluated individually, and also in head-to-head paired comparisons in which each of the seven regimens was compared with every other regimen, for a total of 21 comparisons. Information about the specific attributes of each regimen, and pictures and symbols were used to indicate features such as food requirements, pill size, number of pills and adverse event profiles.
Neither the brand nor the generic names of the medications were mentioned and identifying markers were obscured. The data collected in the survey are not necessarily representative of all HIV+ individuals. The survey population included 299 HIV+ patients ranging in age from 17 to 72 (median 43), 76 percent of whom were males. African Americans comprised approximately 45 percent of participants, Caucasians 38 percent, Hispanics 15 percent and Asian and other ethnic groups made up the remainder. The survey was conducted in six U.S. cities with a high proportion of citizens infected with HIV (Seattle, San Francisco, Miami, New York City, Atlanta and Washington, D.C.).
All individuals who participated in the survey were treatment-experienced with the majority having been on HAART regimens for four years or more. Of 295 patients who responded to a question on their current level of adherence, 26 percent reported no doses missed in the past three months. Another 32 percent said they had missed 1 or 2 doses; 24 percent said 3 to 5, 8 percent said 6 to 8, and 10 percent said 9 or more.
The PASPORT survey was conducted in April 2002 by Cooper Research, Cincinnati, Ohio, and was underwritten by GlaxoSmithKline. Dr. Stone was lead investigator.
GlaxoSmithKline is one of the world's leading research-based pharmaceutical and healthcare companies and an industry leader in HIV research and therapies. The company is engaged in basic research programs designed to investigate new targets to treat HIV.
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