Skip to main content

Table 2 Behavioral model of significant afactors influencing ART adherence among people who inject drugs b

From: Systematic review of HIV treatment adherence research among people who inject drugs in the United States and Canada: evidence to inform pre-exposure prophylaxis (PrEP) adherence interventions

Predisposing Factors Enabling Factors Need-Related Factors Outcomes
Socio-demographic barriers c
• Younger age [25,26,27,28,29,30,31,32, 34, 43, 53,54,55]
• Female sex [25,26,27,28,29, 31, 33, 43, 53,54,55]
• Low education [25, 27, 29, 32, 34, 47]
• Minority (non-White) race/ethnicity [29, 33, 43, 47, 53]
• Low health literacy [52]
• Unemployment [33]
Substance use (SU) barriers
• Heroin use or injection [25, 27,28,29,30, 32, 43, 45, 53,54,55] Stimulant use or injection (alone or with opioids) [25, 27, 28, 30, 43, 47, 52,53,54,55]
• Alcohol use [25, 28, 30, 31, 53, 51]
• Binge drug use, relapse [29, 54] and overdose [25]
• High addiction severity [45] and frequent SU [31]
• SU to cope with stress
Social and structural vulnerability
• Homelessness [25, 28, 29, 53, 54] Incarceration [25, 29,30,31]
• Sexual abuse history [26]
Individual resources
• SU treatment use (medication-assisted therapies; inpatient and outpatient programs) [25, 27,28,29, 32,33,34, 43, 34, 47, 53,54,55]
• Past ART experience [26, 28, 43, 51, 54]
• Self-efficacy for ART use [47, 51] and disclosure [47]
• Stable housing [29, 33, 34]
• Health insurance [30, 34]
• Empowerment [47, 51]
• Social support [33]
Health service facilitators
• Good patient-provider relationships [30, 33, 34, 47]
• Provider experience with HIV care [29, 53]
• Accessible healthcare services [31, 34]
• Directly administered ART (DAART) [50]
Health status barriers
• Markers of poor physical health (detectable HIV viral load, low CD4 count,c AIDS) [29,30,31, 33, 47, 53, 54]
• Poor mental health (depression [33, 34, 45] especially in women [26, 47])
Health beliefs and perceptions
• Perceived health status [47, 51]
• ART-related beliefs [34, 47]
• Sense of responsibility for protecting others [47]
Health risks
• Sex work [25, 29, 53, 54]
• Risky sex partner(s) [26]
• Syringe sharing [47]
• Low self-efficacy for safe drug use [47]
ART adherence measures d
• Pharmacy records [25, 27, 28, 29, 32, 43, 53,54,55]
• Self-report [26, 30, 31, 34, 47, 50,51,52]
• Biological markers [25, 30, 31, 33, 50]
• Electronic monitoring [45]
  1. aSignificant factors defined as results that were statistically significant in univariate, bivariate, or multi-variate models at p < .10. Study references in bold indicate associations significant at p < .10 in final or multivariable models
  2. bAdapted from the Gelberg-Andersen Behavioral Model for Vulnerable Populations. Predisposing factors are characteristics that could directly impact adherence, including socio-demographics, substance use barriers, and related sources of social and structural vulnerability. Enabling factors are resources that could facilitate utilization and be targeted by interventions, including individual resources and health service facilitators (e.g., characteristics of healthcare providers and services). Need-related factors include health status barriers, beliefs and perceptions, and health risks that could also influence adherence
  3. cDirections of associations between CD4 count and adherence outcomes were mixed; unlike the studies referenced in the table, the following studies identified high CD4 count as a barrier to adherence: [27, 28, 32, 34, 43]
  4. dSome studies examined multiple outcomes related to ART adherence. Pharmacy records included prescription refill data. Electronic monitoring was conducted via Medication Electronic Monitoring System (MEMS)