Overall, privately insured people with HIV have inadequate adherence to their daily antiretroviral (ARV) regimen during their first year on treatment and proceed to adhere more poorly as years pass, the National AIDS Treatment Advocacy Project reports.

This finding is the result of a study conducted by Julie Priest, MSPH, and colleagues from ViiV Healthcare and Analysis Group in Boston. Presenting their findings at the IDWeek conference in Washington, DC, earlier this month, the researchers conducted a retrospective analysis of information on people receiving HIV treatment as reflected by the Optum Clinformatics commercial insurance database between January 2011 and December 2017.

The study team relied on the proportion of days covered (PDC) as an indicator of adherence to ARVs. They calculated this figure by looking at the pace of prescription refills and came up with the number of daily doses obtained per 12-month period.

To be eligible for inclusion in the analysis, individuals had to be 18 years old or older and have been continuously enrolled in insurance for at least three months by the time they started ARVs and for at least 12 months after that point.

The analysis included data on 15,153 people, 8,715 (58%) of whom were taking a single-tablet regimen (STR) and 42% of whom were taking a multi-tablet regimen (MTR). Eighty-eight percent of the individuals were men, and 53% lived in the South. The median age was 45 years old.

The proportion of the study members who had a PDC rate of 90% or higher during their first year on ARVs was 63%, including 67% among those on an STR and 58% among those on an MTR. In a subgroup of people who started ARVs between 2014 and 2016, by which time treatment had become simpler and more tolerable, 57% had a PDC rate of at least 90%, including 62% and 48% of those on an STR and MTR, respectively.

During their first, second, third and fourth year on ARVs, the study members had a PDC rate of 90% or greater in 67%, 57%, 57% and 53% of cases, respectively. The corresponding rates for those on an STR were 71%, 63%, 61% and 58%, compared with 63%, 51%, 51% and 46% among those on an MTR.

As for those who started ARVs between 2014 and 2016, a 90% or greater PDC rate was seen among 59% of them during their first year on treatment, a figure that declined to 46% and 42% during their second and third treatment years, respectively. During each of these three successive years of treatment, those on an STR, compared with those on an MTR, had a 90% or higher PDC rate in 64% versus 51% of cases, 53% versus 35% of cases and 50% versus 30% of cases, respectively.

“The use of regimens with lower pill burden or less frequent dosing could improve suboptimal adherence ad achieve higher adherence over time,” the researchers concluded.

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