A commitment contract to achieve virologic suppression in poorly adherent patients with HIV/AIDS

Abstract

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 3 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.

Trial registration: ClinicalTrials.gov identifier NCT01455740.

Conflict of interest statement

Competing Interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the Corresponding Author) and declare: no support from any organization for the submitted work other than from the National Institutes of Health (P30AG034532), the Emory University Center for AIDS Research (P30AI050409), and the Pershing Square Fund for the Foundations of Human Behavior; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work, with the exception of the following: David Laibson is a member of the Scientific Advisory Board of the pharmacy benefit management company Express Scripts, a position for which he does not receive compensation.

Figures

Figure 1

Percent Virologically Suppressed by Study Arm and Visit Number