Scalable Interventions to Increase PrEP Adherence: Value Affirmation and Future Selves

Pre-exposure prophylaxis, or PrEP, is a relatively new HIV prevention method where individuals who are at risk for HIV but do not currently have it take a daily pill (Truvada). The CDC currently recommends PrEP as a method of HIV prevention in high-risk individuals based on compelling efficacy data from large international studies in diverse populations, but the issue of adherence and its relationship to clinical efficacy is still being defined. In five large, randomized and controlled studies, many prospective PrEP patients chose not to take PrEP, and those that did often did not adhere to it consistently (Landovitz \& Coates, 2014). Experts remain unable to answer several high-stakes questions: How do we increase PrEP uptake and adherence amongst those most at risk for HIV, and will starting PrEP increase or decrease high-risk individual sexual behavior and HIV incidence? (Landovitz \& Coates, 2014). In sum, the biggest challenge to reducing new HIV incidence in the U.S. is behavioral, not medical.

Here, the investigators propose a randomized, controlled clinical study to test the effectiveness of a "future selves-value affirmation" behavioral intervention on PrEP uptake and adherence. The intervention is designed to address the challenges of stigma and "present bias" - the individual propensity to place the gains of the moment ahead of future gains- as it relates to adherence.

"Present bias" and the suboptimal decisions it produces derive from a limited ability to imagine one's self in the future, and lead to a patient's preference for smaller, immediate rewards (e.g., escaping side effects of a medication, safeguarding one's situation from loved ones) over larger, delayed ones (e.g., not contracting HIV, longer life expectancy, better health). Research has shown that vivid, concrete, and detailed images of one's future self enhance a person's ability to envision and emotionally engage the future consequences of present-day decisions. For instance, creating positive images of one's future self has been shown to stem delinquent behavior for up to a year (van Gelder, 2013).

To address stigma, the investigators draw on another literature in psychology which has now established that short value affirmation exercises are able to enhance learning, performance, control and commitment outcomes, and to do so most effectively with populations facing stigma in the domain of interest (Vohs \& Smeichel, 2009; Creswell et al., 2013; Creswell \& Lindsay, 2014), especially within the domain of health behavior change (Ehret \& Sherman, 2014; Harris, 2011; Reed \& Aspinwall, 1998; Nustad, 2011; Cohen and Sherman, 2014; Epton et al., 2015). Affirmation exercises can be as simple as writing or talking for 5 minutes about a value one holds dear. Indeed, one such 5-minute exercise at the beginning of a new program or project can lead to profoundly powerful long-term outcomes across very different settings. For example, one intervention led to a .41 point grade increase for minority students in college over the course of one and two years (Cohen et al, 2009), increased decision making skills and use of public service information by homeless shelter participants in Seattle (Hall et al., 2014), and enabled smokers to more readily accept threatening smoking risk information (Epton et al., 2015). This study will combine value affirmation and future selves approaches.

The first study objective is to evaluate the effect of the "future-selves / value affirmation" intervention on PrEP adherence, as measured by tenofovir levels in dried blood spots and categorized via the 5-level ordinal measure for Engagement with PrEP (used in the iPrEx Open-Label Extension). The secondary study objectives are to evaluate the effect of the "future-selves / value affirmation" intervention on HIV and STI contraction at 3, 6, 9, and 12 months, and to evaluate the effect of the "future-selves / value affirmation" intervention on sexual risk behaviors, as self-reported numbers of anal/vaginal sex partners and episodes of condomless receptive anal and vaginal sex at 3, 6, 9 and 12 months.

This is a parallel group randomized trial with 2 arms-a control arm with allocation ratio of 50%, and an intervention arm (future self-value affirmation) with an allocation ratio of 50%. At each clinic visit, participants will engage in a 10-minute writing (or oral, for those with literacy challenges) exercises. Participants in the intervention arm will be given a list of values, asked to select one that has been particularly important to them at critical times in their life, then asked to write about why that value is important to them. Next, those same participants will write a letter to themselves twenty (20) years in the future. Participants in the control arm will first write for 5 minutes about why two values that are least important to them may be important to someone else, and next write a letter to themselves two weeks in the future.

The study includes 170 subjects enrolled across 4 sites in Pittsburgh, with an expectation of retaining 80%, or 135 subjects. Each subject's participation will last for 12 months.The entire study is expected to last for 18 months. The investigators will evaluate concentrations of tenofovir diphosphate (TFV-DP) in dried blood spot samples at baseline and then quarterly visits; they will also perform quarterly evaluations of self-reported numbers of anal/vaginal sex partners and episodes of condomless receptive anal and vaginal sex with and without condoms; incidence of STI and HIV acquisition.

The investigators will employ a mixed ANOVA to look at intervention effects on adherence-as well as STI incidence, and safe sex practices-across time intervals. They will also estimate mixed regression models for the intervention.