[A study on the relapse and its potential causes in pulmonary tuberculosis].

A retrospective cohort study was conducted to acquire the general picture of relapse in pulmonary tuberculosis in China and to clarify the relationship between potential causes and relapse rate. All data were collected from 4,797 initial sputum-positive cases. Results showed: (1) Bacteriological relapse rate within two years after chemotherapy was 4.6%. (2) Cumulative relapse rates within half a year and a year only accounted for respectively 28% and 43% of that within two years after chemotherapy. (3) Patients over 60 years old, with drug-resistant bacilli, with long excretion of bacilli, or with residual cavity(ies) or bacterial-negative conversion of less than 3 months at the end of treatment, were the high risk population of relapse.