Effect of directly observed preventive therapy for latent tuberculosis infection in San Francisco.

Setting: San Francisco TB Clinic instituted a directly observed preventive therapy (DOPT) program for treatment of persons with latent TB infection in 1996.
Objective: To examine therapy completion for latent tuberculosis infection before and after implementation of the DOPT program.
Design: Medical records were analyzed for patients at the San Francisco TB Clinic referred from high-risk sites for the periods 1993-1994 (n = 619) and 1997-June 1998 (n = 460). Treatment completion and time of therapy were analyzed comparing DOPT to self-administered therapy (SAT).
Results: More DOPT patients completed treatment (70.3%) than SAT patients (47.9%) (P < 0.001). Controlling for sex, age, race/ethnic group and cohort, patients on DOPT were nearly twice as likely to complete therapy (OR 1.93, 95% CI 1.25-3.00).
Conclusion: DOPT is a successful strategy. Combined with targeted testing, DOPT can have an important impact in areas with traditionally low rates of treatment adherence.