Adherence to Antiretroviral Therapy in Managed Care Members in the United States: A Retrospective Claims Analysis

BACKGROUND: Antiretroviral therapy (ART) extends life for patients with human immunodeficiency virus (HIV) infection. However, HIV treatment is lifelong, and adherence presents a special challenge. Suboptimal adherence to ART may lead to disease progression and virologic failure. Earlier studies with combination ART demonstrated that as much as 90%-95% adherence was needed to prevent disease progression. OBJECTIVES: To measure adherence to ART regimens in commercially insured patients with HIV infection and analyze the clinical and demographic factors associated with ≥ 90% adherence. METHODS: This study used retrospective claims data from a Mid-Atlantic states MCO. Members 18 years and older with an HIV diagnosis identified by medical claims were included in the cohort, and pharmacy claims were retrieved for these members. An ART regimen was established for each patient within a 120-day period after the last physician’s visit occurring between January 1, 2010, and August 31, 2010. For patients who received an ART regimen recommended by the U.S. Department of Health and Human Services (HHS) 2011 Antiretroviral Guidelines, adherence, as measured by medication possession ratio (MPR), was calculated based on pharmacy claims for 12 months after the end of the 120-day period. Logistic regression was used to examine the association between MPR ≥ 90% and age, sex, type of health plan, use of single-tablet regimens (STR), inpatient and outpatient utilization, and direct health care costs. RESULTS: Of the 4,547 adults with HIV diagnosis, 3,528 (77.6%) had received at least 1 antiretroviral. An HHS-recommended ART regimen was identified in 2,377 patients with 1,136 (47.8%) receiving STR. Mean MPR for patients on an HHS-recommended ART regimen was 91.5% ± 14.0 with 73.1% of patients having achieved MPR ≥ 90%. In univariate analyses, sex, number of outpatient visits, cost of inpatient care, and use of STR were significantly associated with MPR ≥ 90%. In multivariate analysis, only male sex (P = 0.027) and the use of STR (P = 0.009) were positively associated with MPR ≥ 90%. Patients on STR were 1.3 times more likely to achieve at least 90% adherence. CONCLUSIONS: Adherence is a challenge for patients with HIV, and more than a quarter of patients who were on an HHS-recommended ART regimen failed to achieve an accepted adherence MPR threshold of ≥ 90%. Use of STR was associated with an increased likelihood of achieving adherence of at least 90%. Interventions to improve ART adherence are needed, and STR may be an effective strategy as it decreases pill burden.