Effectiveness of DOT for tuberculosis treatment outcomes: a prospective cohort study in Bangkok, Thailand

All health care centres under the Department of Health, Bangkok Metropolitan Administration.

To investigate patterns of drug administration for tuberculosis (TB) patients and to determine whether these patterns affect treatment success rates.

In a prospective cohort study conducted during May 2004 to November 2005, newly diagnosed TB patients aged > or = 15 years were enrolled after giving informed consent. The cohort was followed until treatment outcome. Structured questionnaires were used to interview patients three times: at the first visit, at the end of the intensive phase and at treatment completion. Data were also collected from treatment cards.

Five patterns of drug administration were used in the health centres: centre-based directly observed treatment (DOT), family-based DOT, self-administered treatment (SAT), centre-based DOT + SAT and centre- + family-based DOT. The pattern of drug administration had a significant impact on treatment success (P < 0.001). Using unconditional binary multiple logistic regression controlling for confounding factors, centre- + family-based DOT had the highest success rates compared with centre-based DOT (OR 20.9, 95%CI 5.0-88.3).

The pattern of drug administration impacted on treatment success. Centre- + family-based DOT, family-based DOT and centre-based DOT + SAT achieved higher rates of treatment success than the World Health Organization target. Centre-based DOT had the lowest success.