Agreements with cash incentives boost patient adherence to HIV therapy and rates of viral suppression

People who enter into a contract with their HIV healthcare provider to receive cash incentives in return for high levels of antiretroviral therapy (ART) adherence are more likely to achieve sustained viral suppression compared to people in a control arm, investigators from the United States report in the online edition of AIDS.

The study recruited individuals with ongoing viral replication despite at least six months of ART. Individuals who entered into a commitment contract were approximately four times more likely to have viral suppression compared to individuals in a control arm at an unanticipated follow-up approximately three months after the end of the incentive period.

“This study demonstrated the feasibility of using commitment contracts in HIV care,” comment the investigators. “A notable feature of our study is that after the incentives for ART adherence and provider visits were removed, participants who had been offered a commitment contract for ART adherence were more likely to achieve virological suppression relative to individuals who had been assigned a conditional cash transfer for provider visits and relative to individuals who had been assigned to standard of care.”

Adherence is key to the success of ART. However, many people find it difficult to achieve the high levels of adherence needed for sustained viral suppression. Factors associated with suboptimal adherence include socioeconomic status, mental health and substance abuse.

Research exploring the effect of monetary incentives on ART adherence has had mixed results. Investigators in Alabama wanted to see if offering cash incentives in combination with contracts to adhere to HIV therapy increased rates of viral suppression.

They designed a single-centre randomised controlled trial. People with a detectable viral load (above 200 copies/ml) despite at least six months of ART were eligible for inclusion.

Forty people were recruited to the study. They were randomised into two arms.

Participants in the first arm (21) received a $30 cash incentive to attend their scheduled HIV clinic appointment (provider visit incentive [PVI] arm). Participants in the second arm (19) received a similar $30 cash incentive but in addition to attending their follow-up appointments also entered into an agreement to adhere to their ART (incentive choice [IC] arm). A third study arm consisted of 70 non-randomised individuals with ongoing viral replication despite ART and who received standard of care.

Individuals attended five follow-up visits. Those who entered into a commitment contract only received the $30 cash reward if they took at least 90% of their treatment doses since the last study visit (adherence was assessed using dose-recording pill caps).

Viral load was measured at the fifth study visit and then at an unscheduled study visit approximately three months after the last of the incentivised study visits.

At the fifth study visit, 42% of people who entered into commitment contracts had viral suppression, compared to 38% of people who received incentives for attending appointments and 34% of individuals in the unrandomised control arm. The chances of viral suppression did not differ significantly between the three groups.

At the sixth, unscheduled, visit, 68% of people in the adherence agreement arm were virally suppressed, compared to 43% of people in the appointment incentive arm and 41% of people in the control arm. The chances of viral suppression did not differ between the adherence agreement and appointment incentive groups. However, those who entered into an adherence commitment were approximately four times more likely to have viral suppression compared to individuals in the control arm (aOR = 3.93; 95% CI, 1.19-13.04, p = 0.025).

“Commitment contracts can improve ART adherence and virological suppression,” conclude the authors. They suggest that the commitment contract may have been more effective not only because of the direct incentive, but also because the element of choice gave participants greater feelings of personal engagement and empowerment in management of their condition.