Greater rates of adherence and persistence seen among patients on a single-tablet regimen.
HIV is classified as a retrovirus because it reverses the cell copying process. The virus’ single-stranded RNA uses the enzyme reverse transcriptase to transform into double-stranded DNA to insert itself into a cell’s genome so that cell is “tricked into copying those genes as part of its normal replication process.”1
Antiretroviral therapy (ART) aims to slow this reverse engineering process, to reduce a patient’s viral load. Therefore, for maximum effectiveness, ART should commence as soon as possible after diagnosis and continue indefinitely. HHS recommends initiating ART for 4 reasons:
All ART is combination therapy, whether that be a single-table regimen (STR) or a multitablet regimen (MTR). Because newer treatment options are more potent and tolerable, the authors of a recent study published in Patient Preference and Adherence2 wanted to investigate adherence, persistence, and discontinuation rates among patients newly initiated on ART.
Using IQVIA’s LRx, a pharmacy claims database, for patients who initiated ART between January 1 and May 31, 2016 (known as the index window), the investigators evaluated adherence and persistence of first-line (initial) treatment following a new HIV diagnosis. The study population consisted of 13,127 patients (10,623 on an STR; 2504 on an MTR), and all had to be 18 years or older (mean, 42.8 years) on the index date with no prior claims for ART in the year prior to January 1, 2016. The authors used 2 index dates. For STR, “The index date was defined as the date of the first ART claim within the index window. For patients prescribed an MTR, the index date was defined as the claim date for the last-filled drug in the regimen,” they noted.
Adherence, defined as less than a 5-day gap between prescription refill, was measured over 12 months using 30-day intervals. A larger proportion of patients adhered to STR over both the 12 months and at each interval. These patients were also more persistent with their treatment, meaning if they discontinued treatment for any reason, they took longer to do so after starting. The results also suggest a higher likelihood (60%) of discontinuing (ie, having at least a 90-day gap between refills) ART in 1 year if on an MTR. The main factor, according to the authors, that influences adherence is pill burden, while age (being younger), gender (female), insurance provider (private vs Medicaid/Medicare), and medication history impact persistence.
While the study includes an exhaustive list of limitations, some are key: Even though ART is used just to treat HIV, beyond the pharmacy claims, there were no other clinical data to confirm an HIV diagnosis. This also affects knowledge of comorbid conditions that could have influenced treatment. And throughout the study, the reasons why patients were nonadherent to or discontinued treatment were unknown because researchers were limited to the claims database. Possible reasons include a regimen switch, adverse reactions, and virologic failure.
What do these results and limitations mean? Treatments need to be convenient, the authors say. And although this study builds on existing adherence evidence for STR over MTR, because the study only investigated first-line therapy, further research is warranted in adherence and persistence for the entire treatment trajectory, they noted.
1. Boskey E. How a retrovirus or RNA virus works. Verywell Health website. verywellhealth.com/hiv-is-a-retrovirus-what-does-that-mean-3132822. Published October 25, 2019. Accessed November 12, 2019.
2. Hines DM, Ding Y, Wade RL, Beaubrun A, Cohen JP. Treatment adherence and persistence among HIV-1 patients newly starting treatment. Patient Prefer Adherence. 2019;13:1927-1939.