A comprehensive questionnaire was designed to assess the knowledge and understanding of injecting drug users (IDUs) regarding their HIV disease, and to determine any factors that may increase the acceptance of antiretroviral therapy (ART) by this group. Twenty percent of the total IDU cohort attending the GUIDE (GenitoUrinary Medicine and Infectious Diseases) clinic participated in the study. Fifty-two percent had been homeless in the past 5 years and 84% are unemployed. Seventy-two percent of patients did not complete second level education and 10% were illiterate. Fifty-one percent had siblings or parents with a history of injection drug misuse, and 25% had at least one sibling also HIV positive. Forty-seven percent started using drugs before the age of 13 years, and the most common initial drug was heroin (44%). Ninety-five percent had attended for methadone maintenance therapy (MMT), with 39% currently attending for daily therapy.

The majority of patients were unable to simply explain or interpret CD4 cell counts (54%) and 'viral loads' (65%). Fifty-seven percent of patients were receiving highly active antiretroviral therapy (HAART). There was a statistically significant association between patients receiving HAART and both attendance at a primary care physician for methadone maintenance therapy (P = 0.005), and weekly take-outs of methadone (P = 0.005). There was also an association between adherence to HAART and attendance at a methadone maintenance clinic (P = 0.04). This study highlights the chaotic lifestyle and complex social background of the IDU. Such factors were not, however, associated with acceptance of HAART. The primary factor associated with both the acceptance of and adherence to HAART was regular and stable attendance for methadone therapy.