Time factor in antiretroviral adherence: analysis of adherence to single-tablet regimens versus multiple-tablet regimens over a 5-year period

Background: Adherence is considered the key to the success of treatment with combination antiretroviral therapy (cART). In the past, people receiving cART needed to take several different pills each day (i.e., multi-tablet regimens; MTRs), with this complicated therapy often leading to mistakes, missed doses and sub-optimal treatment. Over the past two decades, advances in the study of AIDS have led to the simplification of treatment regimens, decreasing the number of tablets and daily administrations. Fixed-dose combinations (FDCs), in which two or more drugs are contained in a single dosage form, such as capsule or tablet, were introduced and, in 2006, the first single-tablet regimen (STR), consisting of a combination of three antiretroviral (ARV) drugs, became available. Objective: Compare STR and MTR regimens (2, 3, and 5 tablets/day), in terms of adherence to ARV therapy, over a 5-year period. Setting: Retrospective study undertaken at the Hospital Pharmacy of “Santo Spirito” Hospital of Pescara (Italy), as the unique point of distribution of ARV drugs for HIV patients. Method: By means of PharmaDD.it database, developed by the authors, adherence was calculated as a ratio between received daily dose and prescribed daily dose. Results: Excellent adherence over time for STRs, with an adherence value of 0.98 after 5 years of treatment. Conclusion: Treatment with MTRs was associated with good levels of adherence over time, even though adherence rates were not always optimal with regard to HIV therapy. © 2018, Springer International Publishing AG, part of Springer Nature.