[Research and control of relapse tuberculosis cases].

UNLABELLED: With this symposium, we focused on the relapse of tuberculosis in Japan. Out of 19,893 tuberculosis patients registered in 2007 in Japan, 7.48% were classified as relapse cases. Relapse cases have the risk of acquired drug resistance. But we have few analyses of the proportion of relapse tuberculosis cases with standard short course regimens for six months, factors contributing to tuberculosis relapse and the proportion of drug resistance among relapse TB cases in Japan. Therefore we analyzed the relapse tuberculosis cases in two rural areas and three urban areas. We also analyzed the proportion of drug resistance among relapse cases with the data of drug susceptibility survey of Ryoken. 1. Research of relapse tuberculosis cases: Makoto TOYOTA (Kochi City Public Health Center). To clarify the relapse rate and factors contributing to tuberculosis relapse, we investigated the relapse tuberculosis cases in the municipality where the proportion of elderly tuberculosis patients was high. Out of 902 tuberculosis patients registered in Kochi City Public Health Center during 10 years, 20 pulmonary tuberculosis patients were confirmed relapse cases with initial registered records. Pretreatment cavitations, sputum culture positivity at 2 months, medical miss-management (e.g. number of doses, duration of therapy) and poor adherence were considered to be factors contributing to tuberculosis relapse. Out of 20 relapse cases, 12 cases were detected with symptoms, while only 3 cases were detected by examination in law. 2. A clinical study on relapse cases of pulmonary tuberculosis: Shuichi TAKIKAWA (National Hospital Organization Nishibeppu National Hospital). The relapse of pulmonary tuberculosis was investigated. In the cases with a treatment history before short course chemotherapy, drug resistance rate was high, and thus it needs to be cautious of drug resistance at the time of the retreatment. In the cases with a treatment history of short course chemotherapy, relapse cases were recognized more significantly in male cases aged 70's. In the cases that deviated from the standard treatment and that became impossible to use rifampicin, it should be careful to emergence of isoniazid resistance. 3. The current status of the recurrence tuberculosis cases in Tokyo: Michiko NAGAMINE (Specific Disease Control Section, Tokyo Metropolitan Government Bureau of Social Welfare and Public Health). As for the background of the patient whose disease has relapsed, unstable elements are observed. After any symptom, more patients are diagnosed as a relapse case rather than finding by a medical check up. And more than half are related to homeless or life without fixed address. Their status of insurance is the livelihood protection, no insurance or the national health insurance. By RFLP analysis in Shinjuku city, some clusters have recurrent cases, one of clusters has both a relapse and exogenous reinfection. This is able to elucidate an infectious state. Like this, the analysis of each cluster can help effective countermeasures. 4. Recurrence of tuberculosis in the City of Yokohama between 2004 and 2008: Michihiko YOSHIDA (Shinagawa Public Health Center), Takahiro TOYOZAWA (Yokohama Public Health Center). To identify the TB recurrence rate, we studied a cohort of 40 cases (treatment completion 36 cases, interruption 4 cases) of whom had a previous history of TB treatment including isoniazid and rifampicin. The time for relapse was 7.9 +/- 8.6 years and the overall relapse rate was 0.6% (0.47-0.7%). Our study suggested the relapse was almost equal to the low incident countries but the long-term follow-up and surveillance data should be carefully evaluated. 5. Comparison of the retreatment cases of pulmonary tuberculosis: Yuka SASAKI (National Hospital Organization Chiba-East National Hospital). To investigate the factors of the retreatment of pulmonary tuberculosis, 134 retreatment cases were studied. The factors leading to retreatment were cavitary and large lesions in chest X-p, sputum smear positive and heavy alcohol-drinkers. The factors leading to defaulting of the treatment were lack in understanding of the treatment and their economic problems. Reexamination of the treatment and support of the patients are important to prevent the retreatment of the pulmonary tuberculosis. 6. Proportion of drug resistance among relapse tuberculosis cases, summary of Ryoken studies 1977-2002: Takashi YOSHIYAMA (Fukujuji Hospital).

BACKGROUND AND OBJECTIVE: We have no historical analysis of the proportion of drug resistance among relapse TB cases. Therefore we would like to analyze the proportion of drug resistance among relapse cases in Japan.

METHOD: Re-analysis of the data of drug susceptibility survey of Ryoken from 1977 to 2002.

RESULT: The proportion of relapse cases among Ryoken has decreased in 1982-1987 and that proportion was 10% in 2002. The average age of relapse cases was 5 years older than the new cases and it was 66 years in 2002. The proportion of drug resistance among relapse cases has decreased form 39% (in 1977) to 16% (in 2002) for isoniazid, was stable and around 10% for rifampicin with 7.5% in 2002. The risk factors for drug resistance were younger age, foreigners and part time job. The proportion of drug resistance was higher among cases that were failure with previous treatment, then default with previous treatment and lower among cases with cure/completion at the previous treatment but this tendency was without significance.