The Association of Provider and Practice Factors With HIV Antiretroviral Therapy Adherence

David J. Meyers, MPH; Megan B. Cole, PhD, MPH; Momotazur Rahman, PhD; Yoojin Lee, MS, MPH; William Rogers, PhD, Roee Gutman, PhD; Ira B. Wilson, MD, MSc, FACP


AIDS. 2019;33(13):2081-2089. 

In This Article

Abstract and Introduction


Objective: While antiretroviral therapy (ART) is essential to patients with HIV, there is substantial variation in adherence nationally. We assess how provider and practice factors contribute to successful HIV ART adherence.

Design: We used Medicaid Analytic Extract claims from 2008 to 2012. We attributed patients with HIV to the provider that provided the plurality of HIV-related services or primary care in a given year and assigned these providers to a medical practice based on the National Provider Identifier registry file. We fit successive linear hierarchical models with patient, provider, and practice characteristics to partition the variation in adherence driven by each factor. Our unit of analysis was the patient-year.

Setting: Fourteen US states with the highest HIV prevalence.

Participants: A total of 111 013 patient-years representing 60 496 Medicaid enrollees living with HIV attributed to 4930 providers and 1960 practices.

Main outcome measure: Percentage of year individual patients were adherent to an ART regimen.

Results: Provider and practice random effects jointly explained 6.8% of variation in adherence with patient differences accounted for 45.2% of the variation. Patients seen by generalists and other specialists had a 1.6 [95% confidence interval (CI): 0.6–2.5] and 5.1 (95% CI: 4.1–6.1) percentage point greater adherence than those seen by infectious disease specialists (P < 0.001). Every additional year a patient saw the same provider was associated with a 6% increase in adherence (95% CI: 5.7–6.3).

Conclusion: There is substantial variation in ART adherence attributable to providers and practices and between provider specialties. To improve ART adherence for patients living with HIV, structural aspects of care should be considered.


Timely provision of antiretroviral therapy (ART) to persons living with HIV (PLWH), and the long-term maintenance of such therapy, remains the cornerstone of high-quality HIV care.[1,2] Beginning with the advent of modern ART in the mid-1990s, there has been abundant research focusing on predictors of nonadherence,[3–5] but the vast majority of research has focused on patient-level factors such as age, sex, race, depression, and substance use. While person-level factors are critical, less attention has been given to characteristics of the healthcare system within which PLWH get their care, such as the role of providers or provider practices. These system-level, structural factors may be important drivers of patients' ART adherence, and may be more amenable to interventions than many patient factors.

Some previous work has focused on the role of provider training and expertise on outcomes in PLWH. HIV expertise has been shown to be linked to HIV caseload,[6] and generalist and infectious disease specialists with high HIV volume are equally likely to get their patients on ART.[7] In a study of HIV care quality, well trained nurse practitioners provided care quality that was equal to that of physicians.[8] One study found wide differences in site-level ART prescribing, and that higher site HIV volume was associated with increased ART prescribing.[9] Others have documented large heterogeneity in rates of ART adherence across sites in the United States[10] and sub-Saharan Africa.[11] However, most of these studies were done before modern ART, few examined physician and site characteristics simultaneously, and only one used multilevel modeling techniques.[11]

We used a national sample of Medicaid patients from 2008 to 2012 to examine provider and care practice characteristics associated with ART adherence. The Medicaid population living with HIV is particularly important because Medicaid is the largest source of insurance among PLWH, covering over 40% of all PLWH who receive regular care.[12] We had two main study questions. First, what fraction of variance in patient-level ART adherence can be explained by provider and practice-level effects after adjustment for patient-level factors? Second, in multilevel models, what provider and practice characteristics are associated with ART adherence?