PG-12 Viral suppression among HIV-infected methadone-maintained patients: The role of ongoing injection drug use and adherence to antiretroviral therapy (ART)
Authors: Shrestha Roman , Copenhaver Michael 
Published: April 2019

Introduction:
Methadone maintenance therapy (MMT) is associated with improved virologic outcomes among HIV-infected opioid-dependent individuals, which support the use of MMP as part of the integrated approach to improve HIV treatment and care continuum. However, opioid-dependent individuals stabilized on MMT are highly diverse and beyond the benefit of HIV treatment as prevention (TasP) efforts. Given the critical role of sustained viral suppression in maximizing benefits of antiretroviral therapy (ART), we sought to assess factors associated with viral suppression in patients stabilized on MMT. Identifying subgroups at-risk for not achieving viral suppression and addressing factors causing the disparities could inform approaches to optimize HIV treatment outcomes and prevention efforts (eg, HIV TasP).

Methods:
A sample of 133 HIV-infected, methadone-maintained patients who reported HIV-risk behaviors were enrolled from a community-based methadone maintenance drug treatment facility in New Haven, Connecticut. Participants were recruited through clinic-based advertisements and flyers, word-of-mouth, and direct referral from counselors in the methadone clinic. Participants were assessed using an audio-computer assisted self-interview (ACASI). Multivariable logistic regression was used to identify significant correlates of viral suppression. Additionally, we examined the interactive effect of pairs of variables in the main effects model to determine the moderated effect on viral suppression. Model fit was assessed using a Hosmer and Lemeshow Test.

Results:
The mean age of participants was 49.3 (±8.3) years. The mean duration of HIV diagnosis was 14.1 (±9.6) years and 63.2% of participants reported to have disclosed their HIV status to a sexual partner. Of 121 (91.0%) individuals who were taking ART, 57.9% had achieved optimal adherence, and 80.4% had achieved viral suppression. Self-reported HIV risk behaviors were highly prevalent among study samples. Almost half of participants (46.6%) reported injecting illicit drugs in the past 30 days. Of those, 58.1% reported having shared injection equipment. Similarly, 21.1% of participants reported having sex with more than one sexual partner, and only 14.3% reported always using condoms with their sexual partners in the past 30 days. Having optimal adherence to ART was associated with an over four-fold odds (aOR = 4.883, P = 0.009) and having high CD4 count was associated with a two-fold odds of being virally suppressed (aOR = 2.483, P = 0.045). Additionally, participants who reported having injected drugs in the past 30 days (aOR = 0.081, P = 0.036) were significantly less likely to achieve viral suppression. Furthermore, we found a significant interaction effect that involved optimal ART adherence and injection of drugs on viral suppression (aOR = 2.953, P = 0.029). That is, the influence of optimal ART adherence on viral suppression was reduced due to ongoing injection drug use practices.

Conclusions:
Overall, our findings illustrated how the benefit of MMT programs may be negated among a significant segment of methadone-maintained patients and highlights unaddressed HIV-related treatment challenges faced by this risk group. These findings have important implications for the recently identified concept of HIV TasP as a clinical care strategy to reduce the harmful impact of ongoing HIV replication among HIV-infected individuals as well as transmission risk between serodiscordant couples. As advocates have recently called for the recognition of “undetectable = untransmittable” (U=U) campaign, clinical care of HIV-infected individuals, including those for methadone-maintained patients, could be enhanced by improving communication and counseling about the importance of consistent ART adherence and viral suppression. As such, future interventions should encourage both HIV-infected individuals and their partners to discuss options for HIV and other sexually transmitted infections (STIs) prevention, including HIV and STI treatment, condoms, pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) within substance abuse treatment settings.