(PS2-D77) Perceived Risk of HIV Infection and Self-reported Adherence to Pre-exposure Prophylaxis (PrEP) Among People Who Inject Drugs Engaged in Medication Treatment for Opioid Use Disorder

Background: People with opioid use disorder (PWOUD) are at a starkly increased risk of HIV infection due to a combination of behavioral (e.g., needle sharing, unsafe sexual behavior) and structural risk factors (e.g., substance use stigma, unstable housing, high risk sexual networks). HIV PrEP is highly efficacious in averting new infections among people who inject drugs, but suboptimal adherence to daily oral PrEP frequently undermines effectiveness. Understanding cognitive determinants of PrEP adherence may inform behavioral interventions that reduce HIV risk among PWOUD.

Method: Participants were adults who met DSM-5 criteria for opioid use disorder, were enrolled in an urban medication treatment for opioid use disorder program, had received a prescription for PrEP, and had injected drugs or engaged in condomless sex in the previous six months. A self-report survey was embedded within an ongoing randomized controlled trial testing a behavioral HIV prevention intervention. Past-week PrEP adherence at study baseline was reported using a 0-100% visual analog scale. The Perceived Risk of HIV Scale (subscales: cognitive appraisals, affective appraisals, and salience of risk) measured risk perceptions. Bivariate analyses were conducted using Pearson correlations and independent-samples t-tests. Linear regression was used to control for relevant demographics.

Results: Sixty-one PWOUD completed surveys between December 2019 and October 2022. The sample mean age was 45 years (SD = 10.6), 51% identified as female, 23% Black, 57% White, and 20% Hispanic. One quarter (25%) reported receptive needle sharing, and 43% reported two or more sexual partners in the past month. Over half (53%) reported being unhoused in the past year. Participants reported an average of 56% adherence to their daily oral PrEP regimen in the past week. In bivariate analyses, perceived risk of HIV infection was positively correlated with self-reported PrEP adherence (r = 0.281; p = 0.030), with HIV risk salience most strongly related to adherence (r = 0.343; p = 0.008). These effects remained statistically significant after controlling for gender, which itself was significantly associated with adherence in bivariate analyses with males reporting greater adherence (t (59) = 2.49, p = 0.016). No statistically significant relationships were observed between self-reported HIV risk behaviors (e.g., number of sexual partners) and perceived risk of HIV (p’s > 0.05).

Conclusions: Participants in this treatment-engaged sample of PWOUD reported suboptimal adherence to daily oral PrEP. Those who perceived themselves at greater risk for HIV infection, and those for whom their HIV risk was more salient, reported greater PrEP adherence. A lack of significant relationships between HIV risk behaviors and perceived risk of HIV suggests that PWOUD may not be making accurate HIV risk appraisals. Thus, education-focused interventions that inform HIV risk appraisals may improve PrEP motivation and adherence. These findings should be interpreted with consideration of limitations including a relatively small sample size and a risk of social desirability bias in responding.