A Nested Case-Control Study on Treatment-related Risk Factors for Early Relapse of Tuberculosis

• Published in: American journal of respiratory and critical care medicine 2004-11, Vol.170 (10), p.1124-1130
• Main Authors: Chang, Kwok C, Leung, Chi C, Yew, Wing W, Ho, Suzanne C, Tam, Cheuk M
• Format: Article
• Language: English
• Subjects: Adult; Age Distribution; Aged; Analysis of Variance; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Antitubercular Agents - therapeutic use; Biological and medical sciences; Blood and lymphatic vessels; Blood. Blood and plasma substitutes. Blood products. Blood cells. Blood typing. Plasmapheresis. Apheresis; Cardiology. Vascular system; Case-Control Studies; Directly Observed Therapy; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Follow-Up Studies; Hong Kong - epidemiology; Humans; Incidence; Intensive care medicine; Logistic Models; Male; Medical sciences; Middle Aged; Recurrence; Reference Values; Retrospective Studies; Risk Assessment; Severity of Illness Index; Sex Distribution; Time Factors; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; Treatment Outcome; Tuberculosis, Pulmonary - diagnosis; Tuberculosis, Pulmonary - drug therapy; Tuberculosis, Pulmonary - epidemiology
• ISSN: 1073-449X; 1535-4970
• DOI: 10.1164/rccm.200407-905OC

This nested case-control study aimed at evaluating treatment-related risk factors of relapse of tuberculosis under a service program of directly observed treatment. Out of 12,183 patients with pulmonary tuberculosis who completed treatment within 1 year, 113 relapsed within 30 months after commencement of therapy. The overall 30-month relapse rate was 0.9% (95% confidence interval [CI] 0.8-1.1%). On matching 113 cases with 226 control subjects in a conditional logistic model, thrice-weekly treatment increased the risk of relapse in comparison with daily treatment (odds ratio 3.92, 95% CI 1.78-8.63), whereas prolonging both intensive phase and overall treatment by 50% or more protected against relapse (odds ratio 0.24, 95% CI 0.08-0.70). When pretreatment culture was positive and cavitation was absent, the 30-month relapse rate for standard thrice-weekly regimen was 1.1% (95% CI 0.6-2.0%). The corresponding rates in the presence of cavitation were 7.8% (95% CI 4.0-14.6%) for standard thrice-weekly regimen; 3.3% (95% CI 1.9-5.5%) for standard daily regimen; 0.5% (95% CI 0.1-2.6%) for extended thrice-weekly regimen; and 0.4% (95% CI 0.1-0.9%) for extended daily regimen. Further studies are required to reduce the risk of relapse under program settings.