Development and Validation of a Provider-Specific Anticipated Stigma Scale for People Who Inject Drugs.

Stigma in healthcare settings is a critical barrier to HIV prevention and treatment among people who inject drugs (PWID). While previous tools have measured anticipated stigma, few account for the intersectional and provider-specific experiences of PWID-particularly from syringe service programs (SSPs). We developed and validated the Substance Use Anticipated Provider Stigma Scale (SU-APSS), a multidimensional instrument assessing anticipated stigma from four provider types: healthcare workers, substance use treatment staff, pharmacists, and SSP personnel. Data were drawn from a cross-sectional survey of 264 PWID who were 18 or older, HIV-negative, had injected drugs and used opioids within the past 30 days, and showed visible signs of recent injection. We conducted confirmatory factor analysis (CFA) on responses from 218 participants to evaluate structural validity and used Cronbach's alpha to assess internal consistency. The CFA supported a four-factor structure with strong model fit indices (CFI = 0.97, RMSEA = 0.09 [0.07, 0.11], SRMR = 0.04). All items significantly loaded onto their respective factors (loadings: 0.62-1.06). Internal consistency was high across all subscales (α = 0.85-0.96) and for the overall scale (α = 0.87). Attribution analysis revealed drug use, physical appearance, and income level as the most common perceived reasons for anticipated stigma. The SU-APSS offers a practical tool for identifying provider-specific stigma, informing stigma-reduction interventions, and evaluating implementation strategies to improve HIV prevention and care engagement among PWID.