Self-reported adherence supports patient preference for the single tablet regimen (STR) in the current cART era

To analyze self-reported adherence to antiretroviral regimens containing ritonavir-boosted protease inhibitors, nonnucleoside reverse transcriptase inhibitors (NNRTI), raltegravir, and maraviroc.

Overall, 372 consecutive subjects attending a reference center for HIV treatment in Florence, Italy, were enrolled in the study, from December 2010 to January 2012 (mean age 48 years). A self-report questionnaire was filled in. Patients were defined as "nonadherent" if reporting one of the following criteria: <90% of pills taken in the last month, ≥1 missed dose in the last week, spontaneous treatment interruptions reported, or refill problems in the last 3 months. Gender, age, CD4, HIV-RNA, years of therapy, and type of antiretroviral regimen were analyzed with respect to adherence.

At the time of the questionnaire, 89.8% of patients had <50 copies/mL HIV-RNA and 14.2% were on their first combined antiretroviral therapy. 57% of patients were prescribed a regimen containing ritonavir boosted protease inhibitors (boosted PI), 41.7% NNRTI, 17.2% raltegravir, and 4.8% maraviroc; 49.5% of the subjects were on bis-in-die regimens, while 50.5% were on OD regimens, with 23.1% of these on the single tablet regimen (STR): tenofovir/emtricitabine/efavirenz. The nonadherence proportion was lower in NNRTI than in boosted-PI treatments (19.4% vs 30.2%), and even lower in STR patients (17.4%). In multivariable logistic regression, patients with the NNRTI regimen (OR: 0.56, 95% CI: 0.34-0.94) and the STR (OR: 0.45, 95% CI: 0.22-0.92) reported lower nonadherence. Efavirenz regimens were also associated with lower nonadherence (OR: 0.42, 95% CI: 0.21-0.83), while atazanavir/ritonavir regimens were associated with higher nonadherence. No other relation to specific antiretroviral drugs was found. A higher CD4 count, lower HIV-RNA, and older age were also found to be associated with lower nonadherence, while a longer time on combined antiretroviral therapy was related to higher nonadherence.

STR maintains an advantage in improving adherence with respect to other combined antiretroviral therapies, even though new antiretroviral drugs and drug classes have become available in recent years.