477   Is Illicit Drug Use a Risk Factor for Non-Adherence to Antiretroviral Therapy?

K. A. Gebo*, J .C. Keruly, and R. D. Moore.
Johns Hopkins Univ., Baltimore, MD.

Background:The success of highly active antiretroviral therapy for the treatment of HIV infection is dependent upon strict adherence to complicated dosing regimens.

Methods:We conducted a cross-sectional study of 232 patients, 120 patients with a history of illicit drug use (IDU) and 112 without a history of IDU, on antiretroviral therapy. Patients were interviewed regarding antiretroviral adherence, illicit drug use, health beliefs, and social stress. Percent adherence was defined as the number of doses taken divided by the total number of doses prescribed over a two-week period using the antiretroviral drug least adhered to. Adherence was then dichotomized into adherent (>90% adherence) or non- adherent (<90%) with any antiretroviral medication. Logistic regression was performed to identify risk factors for non-adherence in different patient groups.

Results:A past history of IDU was not associated with non-adherence in our patients. However, a past history of IDU was found to be important to stratify by in further defining factors associated with non-adherence. In patients with a history of IDU, factors associated with non-adherence were the patient's belief that s/he has stress which impedes his/her ability to take medicines as prescribed (odds ration [OR] 2.60, p = 0.007) and heroin use within 6 months of the interview (OR 3.51, p = 0.04). Factors associated in patients without a history of IDU were eating fewer than 2 meals per day (OR 2.36, p = 0.07) and less than strongly believing that it is important to take the medications in the combinations prescribed (OR 5.05, p = 0.002). Factors assessed and found not to be associated with adherence in either group were age, sex, race, CD4 count, alcohol, tobacco, or marijuana use.

Conclusions:Patients with a past history of IDU are not less adherent than those with no history of IDU; however, different factors are associated with non-adherence in IDUs and non-IDUs. Adherence cannot be addressed in a homogeneous manner. Different strategies should be used to improve adherence in IDUs and non- IDUs based upon the specific risk factors in each group.