Interventions Needed to Improve Adherence to Antiretroviral Therapy

San Diego—More than a quarter of patients with HIV treated with antiretroviral therapy (ART) do not adhere to therapy, according to a study presented during a poster session at the AMCP meeting. The poster was titled Adherence to Antiretroviral Therapy in Managed Care Members in the United States: A Retrospective Claims Analysis. The study also found that adherence was significantly improved in people who received a single-tablet-regimen (STR) of ART.

Both of these findings confirm prior studies that have shown lower than desired adherence rates to ART therapy and improved adherence by simplifying treatment with STR. The need to improve adherence is highlighted by studies that show that high adherence rates of 90% to 95% are needed to decrease the risk of treatment failure and progression of HIV to AIDS.

In this study, investigators retrospectively reviewed pharmacy claims of adult patients with HIV from a mid-Atlantic managed care organization to measure adherence to ART regimens as well as to assess the clinical and demographic factors associated with ≥90% adherence. Only patients treated by a recommended ART regimen, as defined by the US Department of Health & Human Services, were included in the study. The ART regimen for each patient was established based on a review of the pharmacy claims during a 120-day window following the most recent office visit prior to September 2010.

The study included 2377 patients, the majority of whom were male (74%) with a mean age of 42.8 years. Most were treated with a regimen of non-nucleoside reverse transcriptase inhibitors (NNRTIs) (56.6%), followed by boosted protease inhibitors (34.2%), integrase inhibitors (6.4%), unboosted protease inhibitors (2.4%), and chemokine (C-C motif) receptor 5 (CCR5) inhibitors (0.3%). Overall, 1,136 (47.8%) received STR.

Medication adherence was assessed for 1 year after the end of a 120-day window defining ART based on the medication possession ratio (MPR). For each ART regimen, the MPR was the sum of the weighted window of use of each ART product × its MPR.

The study found that the mean MPR was 91.5%, and 73.1% of patients were adherent to ART based on an MPR ≥90%.

Based on a multivariate analysis to assess factors associated with adherence to ART, the study found that patients treated with STR were significantly more likely to adhere to treatment (odds ratio, 1.28 [95% confidence interval, 1.07-1.54], P<.009).

Based on these findings, the investigators recommend prescribing STRs as one modifiable factor to improve adherence, but also emphasize the need for other interventions to improve adherence.

Limitations of the study included the lack of assessment of clinical outcomes such as viral load and the lack of distinction between treatment-naïve and treatment-experienced patients. Further limitations included the evaluation of adherence for only 1 year, and the lack of examination of the reasons for nonadherence.

This study was supported by funding from Gilead.