An interesting poster of all patients in the Swiss cohort from 1997-2006 looked at the impact of IDU and access to drug treatment programmes (DTP) on access to ARV and treatment response.

They classified IDU into: (i) former; (ii) DTP (drug treatment program); (iii) DTP with ongoing IDU; or (iv) current drug use without DTP.

Of 8,660 patients, 6091 were never IDU, 1080 former, 741 DTP, 607 DTP with ongoing, and 141 current IDU without DTP.

The odds ratios of being on ART, interrupting ART, and having a viral load below limit of detection, detailed in Table 1 were adjusted for calendar year, sex, age, AIDS, and CD4 count.

Self reported adherence correlated with drug use behaviour, but not to the extent expected. Approximate adherence rates within the previous month were 79%, 70%, 70% 60% and 55% in non-IDU; former IDU; DTP; DTP with ongoing injection behaviour; and current IDU respectively.

Table 1: Odds ratios by IDU definitions compared to non-IDU patients

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Importantly, the likelihood of being on ART and virological outcome were comparable between never- and former-IDU. In contrast, the results differed between the different IDU categories. Former IDU and persons in a DTP were more likely on ART and had an improved virological outcome compared with people currently injecting drugs with or without DTP.

Ref:
Huber M et al. Adherence to antiretroviral treatment (ART) of HIV-infected persons with or without injection drug use (IDU) or in a drug addiction treatment program: the Swiss HIV cohort study. Abstract TUPE0206
http://www.aids2008.org/Pag/Abstracts.aspx?AID=5706