Impact of DOTS and DOTS-plus on multidrug resistant TB: DOTS-plus strengthens, not weakens, DOTS programmes

EDITOR—In their decision analysis Sterling et al hypothesise but offer no evidence that the efficacy of DOTS (directly observed treatment, short course) has ever been diminished by DOTS-plus.1 On the contrary, under the current rigorous procedure for obtaining second line drugs at drastically reduced prices, the Green Light Committee of the World Health Organization assures that only programmes with demonstrably strong DOTS and DOTS-plus components are approved, and then only under the continuous, close supervision of the committee.2

Sterling et al used a 47% cure rate for multidrug resistant tuberculosis under DOTS, but the US Centers for Disease Control and Prevention reported cure rates as low as 5% in Russia.3 Moreover, Migliori et al acknowledged a 25% rate of late failures among patients with chronic multidrug resistant tuberculosis in Russia who were smear negative (and thus considered cured) at the end of treatment, indicating that the true cure rate would be much lower than 47%.4

For treatment of multidrug resistant tuberculosis with DOTS-plus Sterling et al used a 47% cure rate, but Mitnick et al have recently reported a cure rate exceeding 80% in the same setting.5 The cost data used in the authors' analysis do not reflect the greatly discounted prices of the Green Light Committee for second line drugs, whereas the cost used for basic DOTS drugs in India are among the lowest in the world.

Finally, the authors acknowledge that their model did not include the DOTS-plus benefit of preventing further transmission of and mortality from multiple drug resistance—a serious omission. DOTS-plus is now an essential part of global management of tuberculosis, reinforcing the primary goals of control of the disease. It is no more competitive with DOTS than is treating other life threatening diseases such as malaria or pneumonia.