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.,