Should we take a history of prior treatment, and check sputum status at 2–3 months when treating patients for tuberculosis?
Objective: To determine the value of previous treatment history and sputum smear examination at 2–3 months in predicting treatment failure and relapse in tuberculosis patients treated with four drugs given twice weekly for six months under direct observation.
Design: Four cohort studies among 562 ambulant adults with culture positive pulmonary tuberculosis, designed to test the effectiveness of isoniazid 600–900 mg, rifampicin 600 mg, pyrazinamide 2–3 g, and streptomycin 1–2 g, given twice weekly. The same drug regimen was given to all patients irrespective of previous treatment history. Therapy was not changed if smears remained positive at 2–3 months.
Results: Positive predictive values of a history of previous treatment for a positive smear at 2–3 months (18.3%), treatment failure (5.2%), and relapse (9.4%) were poor. Although patients with positive smears at 2–3 months were more likely to fail therapy than patients with negative smears (relative risk = 4.5, 95% Confidence Interval [CI]: 1.6–12.8), positive predictive value for treatment failure was only 12.5%. Although relapse was more frequent in patients with positive smears than those with negative smears (9.7% vs 6.2%; P = 0.4), most patients who relapsed had been smear negative at 2–3 months (18/21).
Conclusion: A four-drug rifampicin-containing regimen can safely be given twice weekly under direct observation to both new and retreatment cases, and the 2–3 month smear examination can safely be omitted.
Document Type: Regular Paper
Affiliations: 1: Centre for Epidemiological Research in Southern Africa, Medical Research Council, South Africa; Division of Tropical Medicine, Liverpool School of Tropical Medicine, UK; and Hlabisa Hospital, Hlabisa, South Africa 2: Centre for Epidemiological Research in Southern Africa, Medical Research Council, South Africa 3: Pinetown Municipality, Pinetown, South Africa 4: Regional Office, State Health Department, Durban, South Africa
Publication date: 1998-01-01
The International Journal of Tuberculosis and Lung Disease publishes articles on all aspects of lung health, including public health-related issues such as training programmes, cost-benefit analysis, legislation, epidemiology, intervention studies and health systems research. The IJTLD is dedicated to the continuing education of physicians and health personnel and the dissemination of information on tuberculosis and lung health world-wide.
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