AMSTERDAM — When injection-drug users living with HIV have easy access to methadone-maintenance therapy, the risk for transmission of the virus is reduced, results from a longitudinal study show.
In fact, study participants spent 30% less time with a viral load above 1500 copies/mL, which is a marker for viral transmission risk.
"The findings suggest that low-threshold methadone-maintenance therapy is an effective intervention in not only halting disease progression, but also curbing onward viral transmission among this key population," said investigator Brittany Barker, a PhD candidate at the University of British Columbia in Vancouver, Canada.
For their study, Barker and her colleagues assessed data on 867 injection-drug users living with HIV from the longitudinal AIDS Care Cohort to Evaluate Access to Survival Services (ACCESS), which were gathered by the BC Centre for Excellence in HIV/AIDS.
The participants — recruited from December 2005 to November 2017 — were receiving antiretroviral treatment and underwent two viral load tests about 180 days apart during the study period.
During the second clinic visit for viral load testing, interviewers asked participants whether they had accessed methadone-maintenance therapy since the previous test.
Sixty percent of participants reported some use of methadone therapy. At the same time, lab results showed that about 67% of participants had surpassed the threshold of 1500 copies/mL during their time in the study.
Crossing the Threshold
"So we had high levels of engagement in methadone but fairly high levels of viral load above the threshold," said Barker, who presented the study results here at the International AIDS Conference 2018.
But more important, engagement in methadone-maintenance therapy was independently associated with a 30% reduction in risk for time with a viral load above 1500 copies/mL, after adjustment for age, sex, daily cocaine use, CD4 count, and residence in an area of downtown Vancouver known for its drug market, Barker reported.
|Table. Risk for Time With a Viral Load Above 1500 copies/mL|
|Characteristic||Adjusted Rate Ratio||P Value|
|CD4 count (for every 100 additional cells)||0.70||<.001|
|Older age (for every additional year)||0.96||<.001|
|Residence in downtown Vancouver||1.13||.089|
|Daily use of crack cocaine||1.34||<.001|
The researchers did not track whether participants with viral loads above 1500 copies/mL transmitted the virus and did not look at whether access to clean syringes contributed to the reduction in risk for transmission.
The participants were recruited from an area in which residents have easy access to free HIV medications and the barrier to methadone therapy is low. These were key to the success of the project, Barker emphasized.
This is a call to action, she told Medscape Medical News. "Our findings support the urgent scale-up of access to evidence-based addiction treatment and the benefit of locating low-barrier HIV treatment and care with addiction treatment services."
This should be "a central component of the effort to control the global pandemic among HIV-positive people who inject drugs," she added.
Although methadone-maintenance therapy for addiction can only be prescribed at methadone clinics in the United States, the study findings are still germane for American providers of HIV care, said Demetre Daskalakis, MD, from the New York City Department of Health and Mental Hygiene.
First, the way the study links methadone access to HIV viral load and onward transmission is innovative. Second, the findings serve as a reminder that "a comprehensive approach to a person living with HIV results in better treatment and therefore better transmission outcomes," said Daskalakis, who treats HIV in addition to his work with the health department.
The study raises the question of whether HIV providers should offer the combination of buprenorphine plus naloxone (Suboxone) to patients who need it, he added. The findings are "perhaps less applicable for methadone and more for Suboxone therapy, which may be routinely prescribed in primary care."
"Special licensing is needed for Suboxone, but the process is quick and becoming less difficult and restricted," he pointed out.
Making it easy for patients to get all their care in one place is essential for better outcomes, said Daskalakis.
"You can't do HIV care in a vacuum," he told Medscape Medical News. For him, the study "reinforces the observation that HIV care is supported by nonclassical HIV interventions."
The National Institutes of Health, Michael Smith Foundation for Health Research, Canadian Research Chairs Program, and Canadian Institutes of Health Research fund the ACCESS study. Barker has disclosed no relevant financial relationships.
International AIDS Conference 2018: Abstract WEAX0101LB. Presented July 25, 2018.
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Cite this: Methadone Lowers HIV Transmission in Injection-Drug Users - Medscape - Jul 31, 2018.