Twenty-year trend of chronic excretors of tubercle bacilli based on the nationwide tuberculosis prevalence surveys in Korea, 1975-1995.

摘要

SETTING: A study of chronic excretors of tubercle bacilli (chronic cases) based on the nationwide random sample surveys of tuberculosis prevalence conducted in Korea from 1975 through 1995. OBJECTIVE: To investigate the temporal trend of the prevalence of chronic cases, and to match these with treatment outcomes and drug resistance rates. DESIGN: Bacillary cases were classified by history of chemotherapy into new (those who denied a history of chemotherapy), non-chronic (those who had taken chemotherapy for less than 2 years) and chronic cases (those who had taken chemotherapy for more than 2 years). RESULTS: Chronic cases decreased from 107 to 12 per 100000 population (annual rate of reduction [ARR] 11.89%) over the 20-year period. The ARR of chronic cases was significantly greater than that of new cases, and accelerated from 1985 (ARR 15.83%), after the application of short course chemotherapy. Rates of overall drug resistance rates increased up to 1980, and those of multidrug resistance up to 1985, followed by a decrease thereafter. A reduction in chronic cases was observed even during the period of increase in drug resistance (including multidrug resistance). CONCLUSION: The prevalence of chronic tuberculosis cases has decreased due to improvements in overall treatment outcome.