[Analysis of prevalence over-estimates for tuberculosis in Okayama Prefecture]

In order to clarify the over-estimates in prevalence rates of tuberculosis, patients originally registered as having tuberculosis and later cancelled from the registration due to change of diagnosis were analyzed. The results were as follows: 1) The patients reclassified due to a change in diagnosis accounted for 6.3% of all reclassified patients. Of all the patients cancelled by the change of diagnosis, the proportion diagnosed as having atypical mycobacteriosis was largest. 2) The patients cancelled due to a change in diagnosis accounted for 6.0% of the patients newly registered as having tuberculosis. 3) The prevalences of all tuberculosis, pulmonary tuberculosis, infectious pulmonary tuberculosis and of bacteriologically positive pulmonary tuberculosis were significantly reduced by corrective adjustments. 4) Analysis for method by which diagnosis was obtained showed that there was a larger proportion of those patients who were reclassified due to change in diagnosis who were diagnosed by mass screening, compared to those reclassified due to correction of disease. The prevalence of cavities was less among the former group than the latter.