Methadone treatment protects against HIV infection: two decades of experience in the Bronx, New York City.

OBJECTIVE: We undertook a study of the role of methadone maintenance in protecting injecting drug users (IDUs) from human immunodeficiency virus (HIV) infection from the earliest days of the HIV epidemic in New York City to the present. The historical context of the epidemic in the Bronx is discussed.
METHODS: For close to two decades, we have been tracking changes in injecting drug use and HIV infection levels in a Bronx cohort study of IDUs. An initial sample of 622 IDUs was recruited from a methadone treatment program in 1985, with historical data going back to 1978. Behavioral interviews and HIV testing were performed and methadone treatment program records (urine toxicology and methadone dose history) were reviewed. We examined both prevalent and incident HIV infections. The sample included African Americans (24.3%), Latinos (50.3%), and white non-Latinos (24.4%). The average methadone dose was 64 milligrams (mg) per day with an average time in treatment of five and a half years.
RESULTS: We found a very low rate of incident infection of 1.7 per 100 person-years observation since 1986. Because of this low rate of infection, we were unable to determine the association between methadone treatment factors and HIV seroincidence. We found that our prevalence data on the 622 IDUs enrolled from 1985 to 1988 yielded strong findings on the role of methadone maintenance in a period when most infections occurred in this population. HIV seroprevalence was 42.9%. Logistic regression analysis revealed associations of methadone dose > or = 80 mg (adjusted odds ratio = 3.07/yr, 95% confidence interval (CI): 1.23-7.68) and last year entered methadone treatment (adjusted odds ratio = 1.22/yr, 95% CI: 1.06-1.41) to HIV infection, independent of year of last cocaine injection, needle sharing in shooting galleries, number of IDU sex partners, low income, and African American of Latino ethnicity.
CONCLUSIONS: Properly dosed, long-term methadone treatment was found to be a central protective factor in preventing HIV infection from the earliest days of the epidemic in New York City. It is crucial to have high quality drug treatment programs in place before an epidemic draws our attention to the inadequacies through excess and unnecessary morbidity and mortality.