The use of nationwide tuberculosis surveillance system data to determine geographical differences in drug resistance--consideration of the representativeness of the drug resistance rate in Japan]

Annual reports of tuberculosis (TB) statistics have been compiled using a database built through the nationwide computerized TB surveillance system in Japan. Using the annual report database for 2007-2009, this study compared the drug resistance rates among eight geographical districts. The proportion of bacteriological test results obtained at public health centers, which enter data into their computers that can then be accessed by the central computer, improved greatly from 2007 to 2009. The proportion of initial culture test results obtained among pulmonary TB increased from 63.8% to 74.8% and the proportion of drug susceptibility test results obtained among culture-positive pulmonary TB cases increased from 41.8% to 63.5%. As a result, susceptibility test results among 15,425 (26.5%) of 58,198 newly notified pulmonary TB cases during the three-year study period were obtained. The proportion of multi-drug resistant (MDR) TB among new treatment patients was 0.6% in the whole country. Although there were no particular districts having a significantly high rate of MDR-TB, the Kinki district showed the highest rate at 0.8%. In the case of retreatment patients, the MDR-TB rate was 5.1% in the whole country and there was no statistical difference among the eight districts. The proportion having resistance to any INH among new treatment patients was 4.5% in the whole country, with the Kinki and Kanto districts showing significantly high rates of 5.3% and 5.2%, respectively. In the case of retreatment patients, the proportion having resistance to any INH was 13.3% in the whole country, and there was no district where the proportion was significantly high. The proportion having resistance to one or more drugs among new treatment patients was 12.7% in the whole country, with the Kinki district showing a significantly higher rate of 15.4%. In the case of retreatment patients, the proportion having resistance to one or more drugs was 22.2% in the whole country, and there was no district where the proportion was significantly high. It is important to monitor drug susceptibility results for a comprehensive TB control program. The results of drug susceptibility tests through the nationwide TB surveillance system revealed a tendency toward higher drug resistance in districts that included large cities. Although many problems remain to be solved in order to optimize the use of results from the nationwide computerized TB surveillance system to represent the drug resistance rates in Japan, this practice is expected to yield great benefits.