Single-tablet regimes biggest predictor of HIV treatment adherence in Brazil

21 March 2019

There were no significant differences in adherence and viral suppression rates between people in relationships and those who are single in Brazil, but the type of regime and pill quantities predict better outcomes.

Couple in Brazil Smiling

Having to only take one pill a day may be the strongest predictor of HIV treatment adherence over all other social, demographic or behavioural factors, reveals a study from Brazil.

The researchers sought to understand antiretroviral treatment (ART) adherence and viral outcomes among heterosexual people living with HIV in stable relationships versus those who were single, which has been seldom researched. It has been theorised that those in stable relationships may be more motivated to be adherent, and results from one other study in Myanmar found that being in a relationship was a strong predictor of ART adherence.

To the surprise of the authors, they found no differences between the two groups. In fact, in this study population, being on a single-tablet regime (STR) over a multi-tablet regime (MTR) was the only independent predictor of treatment adherence.

The study took place in the city of Porto Alegre, which is considered the epicentre of Brazil’s HIV epidemic. Here HIV incidence is nearly twice the rate of the rest of the state and nearly four times Brazil’s national rate.

The study recruited 200 people living with HIV in stable sero-discordant relationships (where one partner is living with HIV and the other is not) and 100 single people living with HIV. All the people living with HIV were in ongoing medical care at a specialist HIV facility and were on ART for at least three months. They completed a computer-based interview to record behavioural and demographic factors, and provided biological markers, including blood samples for viral load, CD4, sexually transmitted infection (STI) assessments and vaginal/ genital secretions for viral load if female. All HIV-negative partners were then counselled and tested for HIV.

Self-reports of good, very good and excellent adherence were classified as “high adherence”. Reports of very little, little and intermittent use of ARV medication in the last month were classified as “poor adherence”. Good adherence was also indicated by viral load in the blood (< 40 copies/ml), as well as genital secretions in women (< 17 copies/ml).

The analysis then verified possible independent associations between stable relationship and ARV adherence controlling for potentially confounding factors such as demographic, behavioural characteristics and ART regimes.

The demographic and behavioural characteristics between the two groups were similar. Most of the study participants were white (62.5%), female (53.6%) and only 52.6% had completed elementary school. The median time on ART was 4.2 years, 59% of the participants were on MTR and the remaining 41% were on STRs.

In this population, 20.3% had CD4 levels below 350 copies/ml, and 22.7% had a detectable viral load – the researchers found no differences between couples and unpartnered participants. They found a statistically significant association between self-reported high adherence and undetectable viral load. There was a trend towards better adherence in those aged over 30, those who were male, and those with higher education. There was no association between adherence and substance abuse or alcohol use.

Further analysis found a significant correlation between those who had an STI (e.g. acquired syphilis, herpes simplex, condyloma (genital warts), gonorrhoea and candidiasis (thrush)) and genital secretion of viral load. The findings underscore the urgent need to screen and treat for these concurrent infections in women living with HIV. However overall, measuring vaginal secretions was not a marker of adherence.

“In summary, our results highlight critical issues pertaining to [ART] adherence and virologic suppression in HIV infected partnered and unpartnered individuals, with the take home message that single tablet ARV regimens may be the most important tool in fostering adherence in our population, regardless of social, behavioural or demographic parameters.”

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Photo credit:
istock/FG Trade

Written by Caitlin Mahon

Content Specialist - HIV & Sexual Health