Directly observed therapy, short-course: The best way to prevent multidrug-resistant tuberculosis

Adherence to therapy in patients with tuberculosis (TB) is a major determin ant of their outcomes. Unfortunately, there are no currently known predicto rs of adherence, given that this phenomenon represents a complex, task-spec ific behavior. Notwithstanding criticisms from civil liberty advocates, dir ectly observed thera py (DOT), facilitated by education, holistic care, ena blers and incentives, is still the best strategy to ensure patient adherenc e to treatment. To enhance delivery of DOT, short-course chemotherapy (SCC) must be strongly advocated. Monitoring of patient progress, dependable dru g supply, and adequate programme funding are other important elements of th e entire strategy. Indeed, since the global resurgence of TB and associated rampant drug resistance in the 1990s, directly observed therapy, short-cou rse (DOTS) has now become the WHO strategy for effective TB control. Data o btained so far in different continents worldwide have underscored the unriv alled efficacy of DOTS in ensuring treatment success and preventing develop ment of acquired drug resistance. The recent WHO/international Union agains t Tuberculosis and Lung Disease (IUATLD) global project on anti-TB drug res istance surveillance has also revealed that countries in which >33-90% of t he population has access to the WHO DOTS strategy have, as a group, lower l evels of drug resistance: primary multidrug-resistant (MDR) (1.4%; median) and acquired MDR index (0.6; median). The use of SCC was also inversely ass ociated with the prevalence of combined resistance to any drug. Countries w ith MDR rates >2% reported using SCC in a median of 70% of their patients, compared with 100% in countries with MDR rates <2% (WHO/TB/97.229). Despite greater initial cost, DOTS is a more cost-effective strategy than self-adm inistered therapy because it decreases the re-treatment costs associated wi th therapy failure and acquired drug resistance. Finally, in addition to ha rnessing the complementary roles of a national tuberculosis programme and c ommunity participation, DOTS might be further enhanced by the use of newly developed drugs with a long duration of action or more potent bactericidal and sterilizing activities.