People who receive opioid substitution therapy to manage drug addiction are more likely to be on antiretroviral treatment and achieve an undetectable HIV viral load, according to study findings published in the journal AIDS.

“These findings are encouraging and support calls for greater integration of OAT [opioid agonist treatment] and HIV services, as well as for interventions to reach people with HIV not on OAT to maximize the clinical and community benefits of antiretroviral therapy,” wrote study authors Stephen Juwono, Eugenia Socías, MD, and colleagues from the British Columbia Centre on Substance Use.

HIV is easily transmitted via shared drug injection equipment, and a substantial proportion of people who use drugs are living with HIV. But this population faces barriers that can make it difficult to start and stay on effective antiretroviral therapy and achieve viral suppression, , including unstable schedules, stigma, poverty, homelessness and incarceration.

Opioid agonist therapy (OAT), which uses medications such as methadone or buprenorphine to prevent withdrawal symptoms and ease cravings for heroin and other opioids, can help people reduce or stop substance use. OAT can lower the risk of overdose death and acquisition of HIV and hepatitis C, and for those already living with HIV, it may improve engagement with care.

Juwono’s team assessed the impact of OAT on progression through the HIV cascade of care for people who use opioids in Vancouver, Canada. The cascade of care involves linkage to care, initiation of antiretroviral therapy, retention in care and ongoing adherence to treatment, and, finally, achieving and maintaining an undetectable viral load, which prevents disease progression and HIV transmission.

About 40% of people who inject drugs in British Columbia are living with HIV. The province’s OAT program provides opioid agonist medications at community-based clinics. Only methadone was available until 2010, when buprenorphine/naloxone (Suboxone) was added to the formulary. In 2017, prescribed oral morphine and injectable heroin (diacetylmorphine) and hydromorphone were added as options. British Columbia provides HIV care and treatment at no cost, removing one potential barrier, but people who are ineligible for financial assistance must pay for OAT through their insurance or out of pocket. HIV-positive people with an opioid use disorder often receive daily directly-observed antiretroviral therapy along with opioid agonists.

This study included 639 people with HIV who used opioids at least once daily. Participants were recruited between 2005 and 2017 as part of the ACCESS (AIDS Care Cohort to Evaluate Exposure to Survival Services) study. A majority (59%) were men, 56% were white and the median age was 42 years. More than 90% had hepatitis C, about a third were homeless, 16% had been incarcerated and 16% reported engaging in sex work. At the start of the study, about 70% were on OAT, mostly methadone.

The researchers found that people on OAT were more likely to be linked to HIV care than those not on OAT (96% versus 93%), though the difference did not reach statistical significance, meaning it could have been due to chance. But people on OAT were significantly more likely to start antiretroviral therapy (91% versus 78%), adhere to treatment (77% versus 54%) and achieve an undetectable viral load (63% versus 42%).

After adjusting for other factors, people on OAT were nearly four times more likely to start antiretrovirals, about three times more likely to adhere to treatment and more than twice as likely to achieve viral suppression.

“This study found a high level of OAT engagement among people with HIV using unregulated opioids and that OAT engagement resulted in significantly increased progression through some of the higher steps of the HIV cascade,” the study authors concluded.

Prior studies have found that use of OAT may increase providers’ willingness to prescribe antiretrovirals and that OAT is associated with better antiretroviral adherence when both are readily available. Taken together, these findings “provide strong evidence of the benefits of OAT for people with HIV who also use opioids, as well as support calls for better integration of OAT with HIV services to improve HIV outcomes among this population,” the researchers wrote.

Click here to read the study abstract.

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