Indicators Used to Measure the Impact of TB Control by World Health Organization
Li-Chun Wu1, Jen Suo2, Jen-Hsiang Chuang3, Chi-Fang Feng4, Cheng-Yi Lee3, 5, Shiang-Lin Yang3, Hsiu-Yun Lo3, 6
2010 Vol.26 NO.3
Correspondence Author： Hsiu-Yun Lo
The indicators of tuberculosis (TB) burden not only estimate the epidemic of TB but also assess the effectiveness of national TB control program. This article introduces the estimation and definition of three indicators-incidence, prevalence, mortality-to measure the impact of TB control program by World Health Organization (WHO).
Estimation of TB burden was based on case notification data in approximately 80% countries in the world. WHO suggested four formulas to estimate TB incidence: (1) adopting case notification and case detection to estimate the incidence; however, if the poor quality of case notification or case detection varies in different periods, incidence would be difficult to estimate; (2) using mortality and case fatality rate to estimate, the incidence would be influenced by the vital statistics system and death coding;(3) estimating incidence with annual infection rate multiplied by Styblo coefficient; and (4) estimating incidence by prevalence divided by duration of disease; however, accurate prevalence and infection rate are difficult to obtain and estimation may vary by different duration of disease. Therefore, the WHO recommended that the completeness and reliability of surveillance data should be improved as much as possible to evaluate the TB burden, especially in morbidity and mortality. The research suggested by adopting the WHO formulas, Taiwan could estimate its TB burden, and monitor these indicators regularly among HIV positive cases and multidrug resistant TB patients.