Lifelong follow-up of inactive tuberculosis: its value and limitations.

There are 14,552 inactive cases of tuberculosis in British Columbia, representing 0.6 per cent of the population. The prevalence of inactive tuberculosis in 7 times higher among Indians than in the remainder of the population. Among all inactive cases, 60.5 per cent of patients had "good" chemotherapy, whereas 13.2 per cent had poor chemotherapy and 26.3 per cent had no chemotherapy. The risk of reactivation in those who received "good" chemotherapy was 2.2 cases per 1,000 persons per annum, whereas for those with poor and no chemotherapy, the risks were 7.8 and 6.7 cases per 1,000 persons per annum, respectively. One third of a sample of all inactive cases were found not to comply with the existing policy of lifelong annual examinations. Of the remaining two-thirds, one-half attended regularly and one-half, irregularly. All reactivations occurring during the 3-year period between 1971 and 1973 were reviewed. The pattern of attendance of these patients during a 3-year period immediately before the year of reactivation was similar to that of the sample of all inactive cases. Sixty per cent of reactivations occurring among "attenders" were diagnosed at such annual examinations. The bacteriologic status of reactivated disease was reviewed; 78 per cent were culture positive. Of patients who had received previous chemotherapy, 45 per cent had organisms that were resistant to one or more of the 3 primary antituberculous drugs, whereas previously untreated groups showed a much lower figure, 7.8 per cent. On the basis of the findings of this study, recommendations are made in relation to future policy of management of inactive cases of tuberculosis.