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The impact of ongoing illicit drug use on virologic suppression in HIV-infected injection drug users receiving HAART
Presented by Harout Tossonian, Canada.
H. Tossonian1, J. Raffa2, J. Grebely1, B. Rashidi1, S. DeVlaming3, B. Conway1
1University of British Columbia, Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver, Canada, 2University of Waterloo, Department of Statistics and Actuarial Sience, Waterloo, Canada, 3Pender Community Health Centre, Vancouver Coastal Health, Vancouver, Canada
Background: To evaluate the impact of ongoing illicit drug use on virologic suppression in HIV-infected injection drug users (IDUs) receiving HAART.
Methods: In a longitudinal, cohort study we identified HIV-infected IDUs who were prescribed HAART either as directly observed therapy (DOT) or self-administered therapy (SAT) between 08/1996 and 08/2007. Urine specimens for toxicology assays were analyzed for amphetamines (A), benzodiazepines (B), cocaine (C) and heroin/opiates (O). The ability to achieve virologic suppression was measured as a function of having a positive or a negative urinalysis for illicit drugs at baseline, as well as 6 and 12 months prior to treatment initiation. Virologic suppression was measured at weeks 24 and 48, based on an intent-to-treat analysis, with virologic failure defined as HIV RNA >400 copies/mL, or having switched or terminated therapy for any reason. Illicit drug use associated with treatment failure was assessed by multiple logistic regression.
Results: A total of 133 IDUs (79 male) were included. HAART regimens were based on PIs (107), NNRTIs (21) and triple NRTIs (5); 115 were DOT and 18 SAT. Virologic suppression was achieved, with having respectively a positive and a negative urinalysis for illicit drugs at baseline, as follows: A (33%/53%), B (60%/49%), C (42%/67%), O (48%/55%) or any A/B/C/O (48%/63%). Similar results were obtained with illicit drug use at the previous 6 and 12 months. After adjusting for potential confounders, having a positive urinalysis result for cocaine at baseline (OR=0.33, 95% CI=0.12-0.87, p=0.026) and in the 6 months prior to treatment (OR=0.29, 95% CI=0.10-0.89, p=0.03) was significantly associated with virologic failure at week 24. Other illicit drug use was not associated with treatment failure at all other assessment points.
Conclusions: With the exception for cocaine, there were no significant associations between illicit drug use prior to treatment and virologic suppression on HAART.
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