September 15, 2013

Single HIV Pill More Likely to Foster Adherence

Published: Sep 14, 2013

By Cole Petrochko, Staff Writer, MedPage Today

Reviewed by F. Perry Wilson, MD, MSCE; Instructor of Medicine, Perelman School of Medicine at the University of Pennsylvania

Action Points

  • This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
  • This observational study demonstrated increased adherence and decreased hospitalizations among veterans taking a "combination" HIV pill compared to those taking multiple pills.
  • Be aware that significant baseline differences existed between these groups, including the fact that the single-pill group was more likely to be treatment-naïve.

DENVER -- Veterans receiving highly active antiretroviral therapy (HAART) were more likely to adhere to treatment and less likely to be hospitalized when taking a single versus multiple tablets, researchers reported here.

Compared with veterans with a multiple-pill treatment burden, single-pill therapy was associated with a nearly two-fold odds of adherence (odds ratio 1.98, P<0.001) and a 31% lower risk of hospitalization (hazard ratio 0.69, P<0.001) at follow-up, according to Scott Sutton, PharmD, of the Dorn Veterans Affairs Medical Center in Columbia, S.C., and colleagues.

Among hospitalizations, single-pill therapy was associated with "a reduced risk of hospitalizations, fewer hospitalizations, and a longer time to hospitalization," Sutton said during an oral session at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

Past research has shown that patients taking single-pill multidrugs were as likely as those taking multipill regimens to switch therapies, though single-pill therapy with the combination efavirenz, tenofovir, and emtricitabine (Atripla) had better odds of controlling HIV, according to data presented at the AIDS Society Conference on HIV Pathogenesis, Treatment, and Prevention July 2013.

Sutton noted that other research has shown that once-daily dosing regimens are preferred by patients and that commercial and Medicaid patient populations receiving single- versus multidrug therapy saw a 24% and 25% respective reduction in risk of hospitalization.

The authors studied the impact of a single-tablet regimen on adherence to HAART versus a multi-tablet regimen, as well as risk and frequency of hospitalization, and differences in viral load between the two treatment groups. The study population consisted of 15,602 veterans (6,191 in the single-ill group and 9,411 in the multi-pill group) receiving care through the VA healthcare system.

Participants received a diagnosis or had past medical history of HIV/AIDS and received a HAART regimen over the course of the study, which contained two nucleoside/nucleotide reverse transcriptase inhibitors and a third agent from another drug class, including non-nucleoside/nucleotide reverse transcriptase inhibitor, protease inhibitor, another nucleoside/nucleotide reverse transcriptase inhibitor, chemokine receptor 5 antagonist, or integrase inhibitor.

Those in the single-tablet group received a complete HAART regimen of a single pill daily over the study period, regardless of prior or subsequent use of different regimens, while those in the multi-pill group received two or more tablets daily and did not receive a regimen of a single tablet daily over the study period.

Participants were followed-up one or more times in the clinic and one or more times in the laboratory 6 months before the index day and had a minimum of 60 days of follow-up after the enrollment date.

Pharmacy fill dates were used to determine adherence to treatment. Additionally, authors recorded data on hospitalizations and whether or not participants had an undetectable viral load.

Mean patient age was 51.6 in the single-tablet group and 52.4 in the multi-tablet group. Each sample was predominantly male (97% versus 98%) and most had a mental health disorder (64% versus 66.5%). Participants were mostly black (49.3% versus 45.4%) or white (40.4% versus 43.7%) and nearly 40% of each group had a drug or alcohol abuse disorder (38.6% versus 39.7%).

More patients in the single-pill group were treatment-naïve(27.5% versus 12.7%), and slightly fewer had an undetectable viral load during the pre-index period (42.1% versus 46.3%). Mean CD4 cell counts were 432.2 cells/mm3 versus 419.3 cells/mm3.

At adherence thresholds of 80% and 95%, those in the single-pill group were significantly more likely to adhere to their treatment regimen. They were also less likely to be hospitalized and the average number of hospitalizations was significantly lower among patients with one or more hospitalizations who had received one pill daily (2.2 versus 2.7, P<0.001).

The proportion of patients with an undetectable viral load from index date to follow also varied significantly at both dates, favoring those in the multi-drug group (P<0.001) at the index date, and the single-drug group at follow-up (63.9% versus 59.6%, P<0.001).

Session co-moderator Joseph Eron Jr., MD, of the University of North Carolina in Chapel Hill, was not sure if the data were conclusive. He noted that adherence from VA patients was extremely high.

"I think if they actually show...when you control for adherence, that the hospitalizations come together, that would impress me," he told MedPage Today, adding that "when they control for adherence [and] there's still a difference between the two groups, then I would worry that there's some channeling bias we're not measuring."

Sutton noted that their study was limited by generalizability, adherence measurements based on pharmacy records, and variance of reporting between clinicians and sites.

The study was supported by Gilead Sciences and the authors received support from the company.

Primary source: ICAAC
Source reference: Stutton SS, et al. "Impact of highly active antiretroviral therapy regimen on adherence and risk of hospitalization in veterans with HIV/AIDS" ICAAC 2013;abstract H-1464.


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