[The effectiveness of pyrazinamide-containing six-month short course chemotherapy].

Incidence of tuberculosis worldwide will increase progressively unless the effective program is implemented immediately. In Japan, the decreasing of tuberculosis incidence has been very slow since 1977 and this trend has not been improved till now. Six-month regimens for the treatment of tuberculosis were recommended by IUATLD, ATS, CDC, and WHO and have been adopted in most developed countries since late 1980s, but not adopted in Japan till April, 1996. We studied effectiveness of 6-month regimen including pyrazinamide (2HRZS or E/4HRE) on newly diagnosed pulmonary tuberculosis who started the treatment in the Fukujuji Hospital, Japan Anti-Tuberculosis Association (JATA). From January 1991 to December 1997, 726 newly diagnosed pulmonary tuberculosis patients started treatment with 6-month regimen. Bacillary negative conversion rate among 424 patients whose bacilli were susceptible to both isoniazid and rifampicin, was 92.9% after 2 months of treatment and who completed treatment without change of treatment regimen. Among 726 cases, 593 (81.7%) succeeded, 48 (6.6%) defaulted, 53 (7.3%) were referred to other doctors, and 32 (4.4%) died. The relapse rate after completion of the treatment was 3.2 percent among 345 patients whose bacilli were susceptible to both isoniazid and rifampicin and who completed the treatment without change of regimen. The relapse rate among the patients complicated with diabetes mellitus (DM) was higher than that among non-DM patients (6.31/100 person-years vs 0.90/100 person-years) (P < 0.001). When drug-induced hepatitis was defined as the elevation of serum liver enzyme levels with the clinical symptoms of hepatitis or their elevation over 5 times of normal upper limit, the incidence of drug-induced hepatitis among the patients treated with pyrazinamide-containing 6-month regimen was not higher than that among the patients treated with 9-month regimen without pyrazinamide (6HRS or E/3HR) (7.9% vs 7.3%). The risk factors for drug-induced hepatitis included elderly, history of gastrectomy, hypoalbuminemia, the higher dose of isoniazid over than 7.5 mg/kg, higher than 30 mg/kg of pyrazinamide and positive HCV antibody. The effectiveness of 6-month regimen on the patients whose organisms were resistant to isoniazid and susceptible to rifampicin was studied. The average duration of the treatment for the patients started 6-month regimen was 3.2 months shorter than for the patients started 9-month regimen (10.2 months vs 13.4 months). I concluded that 6-month regimen containing-pyrazinamide was effective for the patients with isoniazid-rifampicin susceptible tuberculosis patients except the patients complicated with diabetes mellitus. But the frequency of drug-induced hepatitis was higher than that of previous reports, and further studies are needed to elucidate the cause of high frequency of hepatitis among Japanese patients.