By Fran Lowry
There is a dose–response relation between days of missed HIV medications and the subsequent viral load.
The total amount of nonadherent time with HIV antiretroviral therapy over the course of a month affects the risk of having a detectable viral load starting at 14 days, but an interruption of just 2 days will cause the viral load to rise, according to research presented here at the 6th International Conference on HIV Treatment and Prevention Adherence, sponsored by the International Association of Physicians in AIDS Care (IAPAC).
The findings, from an analysis of the MACH-14 study, were presented by Becky L. Genberg, PhD, MPH, from Brown University, Providence, Rhode Island.
There is a dose–response relation between days of missed HIV medications and the subsequent viral load. Moreover, it appears that consecutive days of missed medications of approximately 2 weeks are the most damaging to patient health, compared with shorter interruptions or overall medication-free days, Dr. Genberg said.
“When patients stop taking their medication, their viral load starts to go up almost immediately,” she told Medscape Medical News.
The MACH-14 study combines data from 16 studies at 14 sites in the United States. In this analysis, Dr. Genberg and her team focused on 768 individuals with 2399 viral load measures, and looked at patterns of nonadherence in the 28 days prior to measuring the viral load.
The study sample was 73% male, 42% African American, 34% white, and 17% Hispanic/Latino. The median age was 40 years (interquartile range [IQR], 35 to 46), and 31% were treatment-naïve at baseline. The median viral load was 400 copies/mL (IQR, 400 to 1454).
After adjustment for sociodemographics, total nonadherent days, and time since longest interruption, a dose–response relation between the length of the longest treatment interruption and increased viral load was observed.
The study found that viral load began to increase in as little as 48 hours after discontinuing HIV medication.
After 2 to 6 days, the viral load increased 25%. Between 14 and 20 days, viral load continued to increase significantly (P < .001), and participants whose treatment interruption lasted 3 weeks or longer saw their viral load increase 3-fold, Dr. Genberg said.
“The patterns of adherence seem to matter. We would like a more careful consideration, looking at nonadherence and the different patterns of nonadherence,” she said in an interview. “We would also like to focus on understanding ways to prevent and to intervene to prevent these consecutive treatment interruptions to maximize the effectiveness of treatment.”
“The capacity to pool large datasets is vital to answer questions regarding the impact of different patterns of nonadherence on HIV treatment outcomes,” said conference cochair Christopher M. Gordon, PhD, chief of the Secondary HIV Prevention and Translational Research Branch and associate director for prevention at the National Institute of Mental Health in Bethesda, Maryland.
“These findings have important implications for adherence interventions in both domestic and international settings,” he told Medscape Medical News. “Providers could make more concerted efforts to reduce longer episodes of nonadherence, and in settings where drug stock-outs or other socioeconomic barriers make treatment interruptions more likely, systemic or structural interventions may be needed to prevent these gaps in treatment.”
Jose M. Zuniga, PhD, president of IAPAC and conference cochair, noted that the results of the study “speak directly to a growing call from clinicians, as well as patients, for more sophisticated discussions about the importance of maintaining optimal adherence to antiretroviral therapy.”
He told Medscape Medical News: “ ‘Because I said so’, and ‘because you should’ are no longer strong enough reasons for patients to observe proper medication-taking behaviors.”
Dr. Zuniga added that tools are needed to help clinicians deal with a variety of adherence-related challenges. These include polypharmacy challenges “posed by an aging population of patients on antiretroviral therapy who are taking myriad other drugs, including for comorbid conditions such as cardiovascular disease and/or viral hepatitis.”
This study was supported by the National Institute of Mental Health and the Agency for Healthcare Research and Quality. Dr. Genberg, Dr. Gordon, and Dr. Zuniga have disclosed no relevant financial relationships.
Presented May 23, 2011. 6th International Conference on HIV Treatment and Prevention Adherence: Abstract 70087.
European Aids Treatment Group
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