[Follow-up observation on relapse of smear negative pulmonary tuberculosis after short-course chemotherapy]

To evaluate the efficacy of the tuberculosis (TB) control project supported by WPRO/WHO in Jiangsu province, China, and to analyze the factors associated with relapse.

All registered patients with smear positive pulmonary tuberculosis which were diagnosed and cured in the project, were examined for bacteriological relapse after 2 to 3 years. The relationships among relapse rate, bacterial load and the time of sputum negative conversion were analyzed by historical cohort study.

Fifty seven cases of 1,730 patients who were followed for 2 - 3 years were found smear positive, the relapse rate being 3.29%. The relapse rates in patients whose sputum became negative within two months, within three months and beyond three months after the start of therapy were 2.1%, 5.3% and 8.8% (P < 0.01), respectively.

The long-term result of the TB control project in Jiangsu was good. The relapse rates in patients whose sputum converted negative within three months and beyond three months after the start of therapy were significantly higher than that in patients whose sputum converted negative within two months.