[Discussing the current situation of tuberculosis case-finding by mass miniature radiography in Japan].
The system of tuberculosis (TB) case-finding by mass miniature radiography (MMR) was established and expanded for almost all Japanese citizens in the 1950s. And, as stipulated by the TB Prevention Law, periodic mass screenings for schools, inhabitants, employees and institutions have been carried out. Among those aged over 25 years, the proportion of people screened by MMR was estimated to be 60.3%. This means that about 54 million people aged over 25 years are receiving medical service with MMR every year. However, the detection rates of TB cases by MMR have declined markedly compared with those in 1950s. As of 1998, the detection rate was 0.03 per 1,000 for school children and students, 0.06 per 1,000 for employees, and 0.16 per 1,000 for inhabitants. The proportion of cases detected by MMR among newly notified TB cases was 12.8% in 1998, and this ratio has been almost constant for the last 10 years. This ratio was greater among young adult TB cases. Approximately 20% of notified TB cases aged 20-39 years were detected by MMR for employees. Although the purpose of MMR is to find the cases before discharging TB bacilli, 35.1% of the cases were bacteriologically confirmed, and this proportion was greater among elderly TB cases. The Japan Anti-Tuberculosis Association (JATA) has been carrying out MMR for a long time. Eight selected branches of JATA that has been doing high quality case-finding reported 228 TB cases out of 965,440 inhabitants aged over 40 years examined by MMR in 1996. Based on these results, the cost per TB case detected by MMR was calculated. The cost was 4.4 millions yen (yen) per case for all forms of TB, yen 2.3 millions for male, yen 8.4 millions for female, yen 7.3 millions for those aged 40-49 years and yen 1.8 millions for those aged over 80 years. TB detection rate by MMR for inhabitants was correlated with TB incidence rate in various areas, and based on this correlation, the cost was calculated for various incidence rates. For all forms of TB, the cost was yen 4.0 millions per case for an incidence rate of 30 per 100,000, and yen 6.7 millions for an incidence rate of 20 per 100,000. MMR is not economically cost-effective even among elderly people and in areas with incidence rate less than 50 per 100,000, because the medical expense for a TB patient treated under hospitalization for 2 months and outpatient's clinic for 4 months is approximately yen 0.9 millions in 1996. The decision making in continuation or abolition or limitation of MMR should be discussed from a wide range of cost-effectiveness analyses as well as from the view of public health service and willingness of people. For the purpose of decision making, this study provides the detection rates; the costs stratified by sex, age and incidence; and the proportion of cases detected by MMR among newly notified TB cases by age-group and bacteriological status.
Ohmori
Masako
M
Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, 3-1-24, Matsuyama, Kiyose-shi, Tokyo 204-8533, Japan. ohmori@jata.or.jp
Wada
Masako
M
Uchimura
Kazuhiro
K
Nishii
Kenji
K
Shirai
Yoshinobu
Y
Aoki
Masakazu
M
D000328:Adult; D000368:Aged; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008400:Mass Chest X-Ray / Q000191:economics; D008875:Middle Aged; D014376:Tuberculosis / Q000000981:diagnostic imaging*