Estimation of the number of necessary beds for tuberculosis patients, in Japan

Abstract

To estimate the number of necessary beds for tuberculosis patients in Japan from the view point of isolation of the source of infection. We calculated the number of necessary beds for tuberculosis cases separately for the initial phase and for the chronic excreters. For the initial phase we calculated by multiplying the number of detected tuberculosis cases and the duration of hospitalization. The number of detected cases is based on the figures in 2002 and the duration of hospitalization is assumed to be 90 days for sputum smear positive cases and 60 days for sputum smear negative cases. We calculated the number of necessary beds using the Monte Carlo simulation for each prefecture on the assumption that the incidence and the duration of diseases will be under the effect of random fluctuation with the Poisson's distribution for the number of cases and with the log normal distribution for the duration of hospitalization. We also considered the seasonal fluctuation. Our calculation revealed that around 6,413 beds would be necessary for the initial phase and 200-400 beds for chronic excreters in Japan. There are several prefectures which only requires less than 30 beds. Currently, Japan has around 17,000 beds secured for tuberculosis patients. Our calculation showed that this was much more than needed. In many areas, one ward will provide more than sufficient number of tuberculosis beds. Specialist consultation system must be improved because of the reduction in the number of TB cases treated at hospitals with TB wards and TB specialists. For the treatment of non-infectious TB, ambulatory DOT system, TB shelter and nursing care facilities would be necessary to guarantee compliance to treatment.