Study: Pill count has greatest impact on anti-HIV drug adherence

A study by researchers in six U.S. cities and presented at the 40th annual meeting of the Infectious Diseases Society of America in Chicago on October 26 shows that the total number of pills that need to be taken every day by HIV-positive people for antiretroviral drug therapy plays the greatest role in whether the patients will adhere to their regimens. The study of 227 HIV-positive adults, called "Perspectives on Adherence and Simplicity for HIV+ Patients on Antiretroviral Therapy (PASPORT)," showed that out of 10 characteristics studied, pill burden was ranked as the top factor in adherence. This was followed by dosing frequency, adverse side effects, diet restrictions, pill size, number of refills, number of insurance co-payments, number of prescriptions, number of medication bottles, and the requirement of bedtime dosing.

"In the past, studies have looked primarily at one or two factors related to adherence and measured their impact as single entities," said lead investigator Valerie Stone of Harvard Medical School. "Adherence is a complex problem, and overreliance 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."

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.