Rates of antiretroviral resistance among HIV-infected patients with and without a history of injection drug use.
BACKGROUND
There exist concerns regarding the potential for elevated rates of antiretroviral resistance among HIV-infected injection drug users (IDUs) prescribed highly active antiretroviral therapy (HAART), however, no population-based study has examined if IDUs have elevated rates of antiretroviral resistance in comparison to non-IDUs.


OBJECTIVE
To evaluate the time to the development of antiretroviral resistance among antiretroviral-naive patients with and without a history of injection drug use.


METHODS
In British Columbia there is a province-wide HIV/AIDS treatment program that provides antiretrovirals free of charge. We examined all antiretroviral-naive patients initiating HAART between 1 August 1996 and 30 September 2000 and who were followed to 31 March 2002. The main outcome measure was the time to class-specific antiretroviral resistance. Cumulative antiretroviral resistance rates among IDUs and non-IDUs were evaluated using Kaplan-Meier methods and relative hazards were estimated using Cox regression.


RESULTS
Overall, 1191 antiretroviral-naive patients initiated HAART during the study period. Resistance mutations were observed in 298 (25%) subjects during the first 30 months of HAART. In comparison with non-IDUs, the risk of protease inhibitor resistance [relative hazard (RH), 0.9; 95% confidence interval (CI), 0.5-1.6] and non-nucleoside reverse transcriptase inhibitor resistance (RH, 1.5; 95% CI, 1.0-2.2) were similar among IDUs, and there were no differences in the rates of resistance to the sub-classes of nucleoside reverse transcriptase inhibitors.


CONCLUSIONS
Resistance to all major classes of antiretrovirals were similar among IDUs and non-IDUs after 30 months of follow-up. These findings should help to allay fears that prescribing HAART to IDUs may result in elevated rates of resistance.
British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, Canada.
Evan
E
Wood
Robert S
RS
Hogg
Benita
B
Yip
Winnie W Y
WW
Dong
Brian
B
Wynhoven
Theresa
T
Mo
Chanson J
CJ
Brumme
Julio S G
JS
Montaner
P Richard
PR
Harrigan
D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D024921:Drug Resistance, Multiple, Viral; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy*; D006801:Humans; D008297:Male; D012044:Regression Analysis; D015819:Substance Abuse, Intravenous / Q000150:complications*