Tuberculosis caused by strains that are resistant to at least isoniazid and rifampicin is, by convention, termed “multidrug-resistant tuberculosis.” (1) A report has recently been published on work in a referral centre in Turkey that has a full complement of clinical, laboratory, and surgical services, including multidrug treatment regimens given for 18 to 24 months, resources for the management of side effects, adjuvant surgery when necessary, and full financial and nutritional support (2). The report indicates that with a high standard of care, the treatment of multidrug-resistant tuberculosis can have excellent results, especially among younger patients without serious coexisting conditions.
Mycobacterium tuberculosis is an airborne pathogen and persons with active pulmonary tuberculosis caused by a multidrug-resistant strain can transmit the disease to others as long as they are alive and coughing. Throughout the world, most patients with multidrug-resistant tuberculosis are like the majority of those in the Turkish study: young and middle-aged adults who are not infected with HIV and who do not have serious coexisting conditions. Almost none of these patients, however, are receiving effective therapy, and most remain infectious.
It is often argued that multidrug-resistant tuberculosis is too expensive and too difficult to treat. The authors of the current study take note of the debate about “whether to consider multidrug-resistant tuberculosis treatable or untreatable, given the often limited resources available.” Some have claimed that multidrug-resistant tuberculosis can be treated with a short course of chemotherapy (i.e., treatment based on isoniazid and rifampicin, the very drugs to which multidrug-resistant strains of M. tuberculosis are, by definition, resistant). It was not until last year that this misconception was put to rest. In a six-country study, the cure rates among patients with laboratory-documented, multidrug-resistant tuberculosis were well under 50 percent in most settings (3) In a study in Ivanovo Oblast, Russia, only five percent of patients with multidrug-resistant tuberculosis were cured by short-course chemotherapy (4). Moreover, delays in establishing the diagnosis and initiating effective therapy are associated with poor outcomes, even when patients do finally receive effective therapy. In accordance with the current public health convention, all patients in Turkey who have smear-positive pulmonary tuberculosis receive empirical short-course chemotherapy based on isoniazid and rifampicin.
That patients with multidrug-resistant tuberculosis are going untreated raises the general question of the standards of care for patients with chronic infectious diseases who have the misfortune to live in impoverished countries. The assumption that these diseases are treatable in some places and not in others is widely accepted. A lack of infrastructure is commonly cited as the justification for lower standards of care in some countries, but the real issue is cost. It has been argued that the high cost of “second-line” antituberculosis medications makes the treatment of multidrug-resistant tuberculosis problematic in poor countries. However, the prices of these medications, which have long been off patent, are exorbitant because there has not been a concerted effort to treat patients who have tuberculosis and who live in poverty (5). The destitute sick generate no perceptible demand in the medical marketplace.
1. Farmer, P. New England Journal of Medicine, 345: 208 - 210 (2001).
2. Tahaolu, K., TîrÅn T., Sevim T. et al. The treatment of multidrug-resistant tuberculosis in Turkey. New England Journal of Medicine, 345: 170-174. (2001).
3. Espinal, M.A., Kim, S.J., Suarez, P.G., et al. Standard short-course chemotherapy for drug-resistant tuberculosis: treatment outcomes in 6 countries. Journal of the American Medical Association; 283: 2537-2545 (2000).
4. Primary multidrug-resistant tuberculosis - Ivanovo Oblast, Russia, 1999. Morbidity and Mortality Weekly Report, 48: 661 - 664 (1999).
5. Kim, J.Y., Furin, J.J., Shakow, A.D. et al. Treatment of multidrug-resistant tuberculosis (MDR-TB): new strategies for procuring second-and third-line drugs. International Journal of Tuberculosis and Lung Disease; 3 Suppl 1: S81 - S81 (1999).