Psychosocial determinants of adherence to highly active antiretroviral therapy among injection drug users in Vancouver.
BACKGROUND
Sub-optimal adherence to highly active antiretroviral therapy (HAART) among injection drug users (IDUs) is a significant concern. As such, there is an urgent need to identify psychosocial determinants of adherence that can be incorporated into interventions designed to promote optimal adherence.


OBJECTIVE
To identify psychosocial determinants of adherence to HAART, as well as self-reported reasons for missing doses of HAART among HIV-infected IDUs.


METHODS
We developed an eight-item adherence self-efficacy scale comprised of two sub-scales: adherence efficacy and self-regulatory efficacy. We examined correlates between adherence self-efficacy, outcome expectations, socio-demographic characteristics, drug use and risk behaviours, social support and HAART adherence among 108 HIV-infected participants in the Vancouver Injection Drug Users Study (VIDUS). Pharmacy-based adherence to HAART was obtained through a confidential record linkage to the province of British Columbia's HIV/AIDS Drug Treatment Program. Participants were defined as adherent if they picked-up 95% of their HAART prescriptions. Participants were also asked to indicate reasons for missing doses of HAART. Logistic regression was used to identify the factors independently associated with adherence to HAART.


RESULTS
Seventy-one (66%) HIV-infected IDUs were less than 95% adherent. Forgetting was the most frequently cited reason (27%) for missing doses of HAART. Factors independently associated with adherence to HAART included adherence efficacy expectations [OR=1.8 (95% CI: 1.0-3.1); P=0.039] and negative outcome expectations [OR=0.8 (95% CI: 0.7-0.9); P=0.027].


CONCLUSIONS
We found low rates of adherence to HAART among IDUs. Psychological constructs derived from self-efficacy theory are highly germane to the understanding of adherence behaviour, and interventions that address these constructs should be developed and tested among HIV-infected drug users.
Kerr
Thomas
T
Canadian HIV/AIDS Legal Network, Montreal, Que., Canada. tkerr@aidslaw.ca
Palepu
Anita
A
Barness
Gordon
G
Walsh
John
J
Hogg
Robert
R
Montaner
Julio
J
Tyndall
Mark
M
Wood
Evan
E
D000328:Adult; D044966:Anti-Retroviral Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active / Q000523:psychology*; D002170:Canada; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy* / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance / Q000523:psychology*; D012044:Regression Analysis; D012309:Risk-Taking; D012944:Social Support; D015819:Substance Abuse, Intravenous / Q000150:complications / Q000188:drug therapy* / Q000523:psychology; D011795:Surveys and Questionnaires
D044966:Anti-Retroviral Agents