A Commitment Contract to Achieve Virologic Suppression in Poorly Adherent Patients with HIV/AIDS

Objective: Assess whether a commitment contract informed by behavioral economics leads to persistent virologic suppression among HIV-positive patients with poor antiretroviral therapy (ART) adherence. Design: Single-center pilot randomized clinical trial and a nonrandomized control group. Setting: Publicly funded HIV clinic in Atlanta, Georgia, USA. Intervention: The study involved three arms. First, participants in the provider visit incentive (PVI) arm received $30 after attending each scheduled provider visit. Second, participants in the incentive choice arm were given a choice between the above arrangement and a commitment contract that made the $30 payment conditional on both attending the provider visit and meeting an ART adherence threshold. Third, the passive control arm received routine care and no incentives. Participants: A total of 110 HIV-infected adults with a recent plasma HIV-1 viral load more than 200 copies/ml despite ART. The sample sizes of the three groups were as follows: PVI, n=21; incentive choice, n=19; and passive control, n=70. Main outcome measure: Virologic suppression (plasma HIV-1 viral load<=200 copies/ml) at the end of the incentive period and at an unanticipated postincentive study visit approximately three months later. Results: The odds of suppression were higher in the incentive choice arm than in the passive control arm at the postincentive visit (adjusted odds ratio 3.93, 95% confidence interval 1.19–13.04, P=0.025). The differences relative to the passive control arm at the end of the incentive period and relative to the PVI arm at both points in time were not statistically significant. Conclusion: Commitment contracts can improve ART adherence and virologic suppression.