Dispensation of Antiretroviral Therapy and Methadone Maintenance Therapy at the Same Facility in a Low-Barrier Setting Linked to Optimal Adherence to HIV Treatment

NA Mohd Salleh; N Fairbairn; S Nolan; R Barrios; J Shoveller; L Richardson; M-J Milloy

Disclosures

HIV Medicine. 2019;20(9):606-614. 

In This Article

Abstract and Introduction

Abstract

Objectives: We sought to examine the association between dispensation of methadone maintenance therapy (MMT) and antiretroviral therapy (ART) at the same facility, across multiple low-barrier dispensing outlets, and achieving optimal adherence to ART among people who use illicit drugs (PWUD).

Methods: We used data from the AIDS Care Cohort to Evaluate Exposure to Survival Services (ACCESS) study, a long-running study of a community-recruited cohort of HIV-positive PWUD, linked to comprehensive HIV clinical records in Vancouver, Canada, a setting of no-cost, universal access to HIV care. The longitudinal relationship between MMT-ART dispensation at the same facility and the odds of ≥ 95% ART adherence was analysed using multivariable generalized linear mixed-effects modelling. We conducted a further analysis using a marginal structural mode with inverse probability of treatment weights as a sensitivity analysis.

Results: This study included data on 1690 interviews of 345 ART- and MMT-exposed participants carried out between June 2012 and December 2017. In the final multivariable model, MMT-ART dispensation, compared with nondispensation at the same facility, was associated with greater odds of achieving ≥ 95% adherence [adjusted odds ratio (AOR) 1.56; 95% confidence interval (CI) 1.26–1.96]. A marginal structural model estimated a 1.48 (95% CI 1.15–1.80) greater odds of ≥ 95% adherence among participants who reported MMT-ART dispensation at the same facility compared with those who did not.

Conclusions: The odds of achieving optimal adherence to ART were 56% higher during periods in which MMT and ART medications were dispensed at the same facility, in a low-barrier setting. Our findings highlight the need to consider a simpler integrated approach with medication dispensation at the same facility in low-threshold settings.

Introduction

The use of antiretroviral therapy (ART) is a central part of global efforts to control the HIV pandemic by reducing viral transmission rates and HIV-related morbidity and mortality among people living with HIV (PLHIV).[1] At the individual level, the effectiveness of the seek, test, treat and retain approach relies on high levels of adherence to ART to ensure durable plasma HIV-1 RNA viral load suppression.[2] There are long-standing concerns that people who use illicit drugs (PWUD) may be less likely to achieve optimal adherence to ART[3] as a result of both behavioural and social-structural factors such as untreated substance use disorders, poor health care utilization and socio-economic marginalization, including unmet subsistence needs.[4–6]

As a consequence of its beneficial effects on the health and wellbeing of PWUD with opioid use disorder (OUD), methadone maintenance therapy (MMT) is a vital component of a comprehensive HIV care package for members of this key population.[7] The use of this long-acting synthetic opioid has clearly demonstrated a reduction in illicit opioid use and high-risk injection practices as well as improved engagement in addiction care.[8] Further, provision of take-away dosing and higher MMT doses has been associated with achieving optimal ART adherence, which in turn is strongly linked to positive immunological and virological outcomes.[9–11] Beyond its stabilizing effect on opioid use,[12] the positive association between MMT use and ART outcomes can be partly explained by the role of MMT as an important point of contact which facilitates entry into HIV care through HIV testing and referral services.[13] Effective service delivery that meets the needs of PWUD may similarly involve strong collaboration between HIV and addiction specialists.

In current health systems, many care models for HIV-positive PWUD have emphasized the integration of HIV care and treatment for OUD to ensure that the clinical management of HIV infection enhances health outcomes in this population.[14–19] For example, previously described elements of integration include screening for substance use disorder or HIV infection at either facility, combining screening with an established referral mechanism, cross training of specialists, integrating care under the same management team, and integrating care into community or residential settings.[14,15,20] Overall, these coordination processes are significant steps towards achieving a fully comprehensive integrated health care model for PWUD living with HIV.

In Vancouver, Canada, PWUD have access to no-cost, low-barrier opioid agonist treatment if they are in receipt of income assistance or below a certain income threshold.[21] The dispensation of MMT, prescribed by licensed primary care physicians under the provincial health care programme, is not constrained within specialized substance use clinics but is widely accessible through community outlets, including general pharmacies and physicians' offices.[10] In this model, programmatic barriers that may limit treatment accessibility, which may include long waiting lists or prerequisites to enter the programme, are reduced.[21] Additionally, authorized pharmacies such as general hospitals and medical centres treating HIV-positive individuals may deliver ART medication to these low-barrier locations for final dispensation, enabling dispensation of MMT and ART at the same facility. This wide coverage of dispensation for both treatments in a low-barrier setting has therefore offered convenience for patients who experienced difficulties in accessing mainstream health services.

Despite high-profile calls for an integrated approach for treatment of OUD and concurrent HIV infection,[16] existing studies on co-dispensation of treatment medications have mainly focused on integrated care at a single location or specialized clinics, and the use of MMT with directly administered ART,[13,17,18] a strategy to promote ART uptake in which a health worker dispenses and observes a patient taking daily doses of medication. However, there is a gap in understanding the longitudinal effect of the dispensation of ART and MMT on ART adherence among PWUD using data from real-world settings such as those with multiple low-barrier dispensation outlets in the community as a part of regular clinical care. In the current study, we therefore sought to assess the potential impact of dispensation of ART and MMT at the same facility across multiple low-threshold settings (i.e. primary care physicians' offices, community pharmacies, or other health care facilities) on adherence to ART among HIV-positive PWUD. We hypothesized that dispensation of MMT and ART at the same facility, in a low-threshold setting, would be associated with greater odds of achieving ≥ 95% adherence among HIV-positive PWUD in Vancouver, where all persons living with HIV are entitled to access free ART as part of a universal no-cost health care system.

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