A randomized trial comparing standard outcomes in two treatment models for substance users with tuberculosis

Chicago Department of Public Health (CDPH), TB Control Program.

To compare anti-tuberculosis treatment outcomes using two different types of directly observed therapy (DOT) outreach workers.

Substance users diagnosed with TB from October 1996 to July 2000 were randomized to DOT administered by either 1) CDPH personnel (standard arm) or 2) previous substance-using human immunodeficiency virus/acquired immune-deficiency syndrome outreach workers (enhanced arm). Treatment completion was physician-determined, and adherence was estimated based on risk of missed DOT appointments.

Of 94 patients, 46 were randomized to the standard and 48 to the enhanced arm. The standard arm had a significantly higher risk of non-completion of treatment (39% vs. 15%, RR 2.7, 95%CI 1.2-5.8), and a significantly higher risk of missing DOT appointments (RR 2.6, 95%CI 1.4-4.8). For both outcomes, housing instability was a significant predictor in multivariate analyses.

TB treatment completion and adherence among substance users was improved by the enhanced intervention; the familiarity of enhanced-arm DOT workers with the patients' social norms due to their own previous substance use may have made them more effective. Successful DOT in hard-to-reach populations may require strategies that directly address the population's circumstances and utilize DOT workers who are intimately familiar with patients' life situations.