Rates of Inappropriate Antiretroviral Prescription Among Injection Drug Users

Background: Although the survival benefits of antiretroviral therapy (ART) for the treatment of HIVinfection are well established, the clinical management of HIV disease continues to present majorchallenges. There are particular concerns regarding access to appropriate HIV treatment among HIVinfectedinjection drug users (IDU).Methods: In a prospective cohort study of HIV-infected IDU in Vancouver, Canada, we examined initialART regimens vis-à-vis the provincial government's therapeutic guidelines at the time ART was initiated.Briefly, there have been four sets of guidelines: Era 1 (1992 to November 1995; double-drug (dual NRTIs)ART for patients with a CD4 cell count of 350 or less); Era 2 (December 1995 to May 1996; double-drugtherapy for patients with a CD4+ cell count of 500 or less); Era 3 (June 1996 to June 1997; triple-drugtherapy (dual NRTIs with a PI or NNRTI) for patients who had a plasma viral load of > 100,000 HIV-1RNA copies/mL; dual therapy with two NRTIs for those with a plasma viral load of 5,000 to 100,000 HIV-1 RNA copies/mL); Era 4 (since July 1997; universal use of triple drug therapy as first-line treatment).Results: Between May 1996 and May 2003, 431 HIV-infected individuals were enrolled into the cohort.By May 31, 2003, 291 (67.5%) individuals had initiated ART. We noted instances of inappropriateantiretroviral prescription in each guideline era, with 9 (53%) in Era 1, 3 (12%) in Era 2, 22 (28%) in Era 3,and 23 (15%) in Era 4. Of the 57 subjects who received an inappropriate ART regimen initially, 14 neverreceived the appropriate therapy; among the remaining 43, the median time to the initiation of a guidelineappropriateART regimen was 12 months (inter-quartile range 5 – 20).Conclusion: The present study identified measurable rates of guideline-inappropriate ART prescriptionfor patients who were injection drug users. Rates were highest in the era of dual therapy, although highrates persisted into the triple-therapy era. As therapeutic guidelines continue to evolve, it is critical thatmechanisms be put in place to ensure prescription of ART combinations for IDU that are consistent withcurrent expert recommendations.