[Analysis of chronic excretors of Mycobacterium bacilli in Aichi Prefecture]

Among the patients diagnosed as having pulmonary tuberculosis who were newly admitted to six major tuberculosis centers in Aichi Prefecture during the period from January 1, 1982 to December 31, 1986, 73 patients were chronic excretors of Mycobacterium bacilli (chronics), whose sputum cultures tested positive at both 11 and 12 months after admission. In this study, those 73 patients were analyzed in March 1988. If the patient was still hospitalized at that time, the patient was re-evaluated six months later. The life table method was used for analysis of clinical procedures. For the analysis of risk factors for chronics, 37 patients who were treated after 1971 when RFP was available for treatment were used. The results in this study are as follows: 1. A total of 49.3% of the patients were determined chronics (those who had initial chemotherapy before 1970 when RFP was not available). This result suggests that the use of RFP may contribute to the reduction of chronics. 2. Patient delay in diagnosis, as well as irregular chemotherapy, was one of the factors for the development of chronics. 3. In the chronics, many patients showed severe findings in their chest X-rays, high bacillary counts in the sputum, and low drug-sensitivity bacilli when treated with the major anti-tuberculosis drugs. 4. The rate of chronics from newly admitted patients with positive sputum cultures following the initial chemotherapy treatment was 1.3%. This rate could increase following longer observation periods. 5. Chronics were more prevalent in patients with Type I (extensive cavitary type) findings in the chest X-rays, and positive sputum smears for Mycobacterium bacilli in the clinical findings when compared with all newly registered active tuberculosis patients during the same period in Aichi Prefecture. 6. Concerning the outcome, 55 patients were discharged (17 improved; 13 personally released; 25 deceased) while 18 remain hospitalized. Among those discharged patients, 17 patients were released as a result in improved health while 25 died. These results indicate poor prognosis. Using the life table method, the estimated mortality rate is 49.7%, and the negative sputum rate is 30.5% five years later. 7. Using a multivariate analysis on the prognosis, the risk factor was greatest for poor prognosis for those patients who had Type I findings in their chest X-rays, initial chemotherapy before 1970, complications, and that were male. 8. The patients with improved health, were more sensitive to the drugs applied when compared to the fatal patients. 9. Careful chemotherapy during the first two years may contribute to the reduction of chronics.