Adherence to highly active antiretroviral therapy in the homeless population in San Francisco: a prospective study.

Background: We examined adherence to highly active antiretroviral therapy (HAART) in the homeless population, a population thought to be at high risk for poor adherence to therapy and for development of drug-resistant strains of human immunodeficiency virus (HIV).
Methods: We performed a 12-month prospective study of 148 persons receiving HAART who were identified in a stratified screening of the homeless and marginally housed. We sampled in lunch lines, shelters, and hotels in 3 neighborhoods of San Francisco, California. We used pill counts at unannounced home visits as the primary measure of adherence.
Results: Of 148 individuals sampled, 46 (31%) discontinued HAART during the study. Average adherence in the group of those who discontinued HAART was 51%, and 9% of these subjects had undetectable virus loads (i.e., <400 copies/mL) at the last follow-up visit. Predictors of discontinuation of therapy were depressive symptoms, injection drug use, African American ethnicity, and early poor adherence. Of 148 subjects, 102 (69%) continued to receive HAART throughout the study period. Average adherence in the group of those who continued to receive HAART was 74%, and 55% of these subjects had undetectable virus loads at the last follow-up visit. Predictors of lower average adherence in this group were African American ethnicity and use of crack cocaine; men who had sex with men had higher adherence.
Conclusions: One-third of homeless and marginally housed persons receiving HAART discontinued therapy during the follow-up period and would benefit from adherence interventions directed at sustaining therapy; two-thirds continued to receive therapy at adherence levels comparable to those found with other clinical populations.