Psychometric Evaluation and Predictive Validity of an Adapted Adherence Self-Efficacy Scale for PrEP

Area of Science:

• Psychology
• Public Health
• Infectious Diseases

Background:

• Adherence to HIV pre-exposure prophylaxis (PrEP) is vital for preventing HIV transmission.
• Adherence self-efficacy, or confidence in medication adherence, is a key predictor of health behavior but is understudied in PrEP.
• Existing measures may not fully capture self-efficacy specific to PrEP regimens.

Purpose of the Study:

• To psychometrically evaluate and validate the PrEP Adherence Self-Efficacy Scale (PrEP-ASES).
• To adapt and assess the reliability and validity of the PrEP-ASES in diverse populations.
• To examine the association between self-efficacy and PrEP uptake, adherence, and sustainment.

Main Methods:

• Adapted the HIV Treatment Adherence Self-Efficacy Scale (HIV-ASES) to create the PrEP-ASES.
• Conducted factor analyses on data from two studies involving gay and bisexual cisgender men and transgender women.
• Assessed test-retest reliability and correlated PrEP-ASES scores with PrEP usage metrics.

Main Results:

• Factor analysis supported a robust one-factor score, explaining 75.3% of the variance.
• The PrEP-ASES demonstrated good test-retest reliability (rs > 0.40).
• Higher PrEP-ASES scores were significantly associated with increased PrEP uptake, adherence, and sustained use in both study groups.

Conclusions:

• The PrEP-ASES is a psychometrically sound and reliable measure for assessing self-efficacy in PrEP users.
• The scale is useful for research evaluating PrEP adherence interventions.
• Findings highlight the importance of addressing self-efficacy within PrEP programs to improve adherence and long-term effectiveness.