A Study on the Relapse Rate of Tuberculosis and Related Factors in Korea Using Nationwide Tuberculosis Notification Data
OBJECTIVE To identify risk factors associated with relapse among cured tuberculosis (TB) patients in a DOTS programme in South India. DESIGN Sputum samples collected from a cohort of TB patients registered between April 2000 and December 2001 were examined by fluorescence microscopy for acid-fast bacilli and by culture for Mycobacterium tuberculosis at 6, 12 and 18 months after treatment completion. RESULTS Of the 534 cured patients, 503 (94%) were followed up for 18 months after treatment completion. Of these, 62 (12%) relapsed during the 18-month period; 48 (77%) of the 62 relapses occurred during the first 6 months of follow-up. Patients who took treatment irregularly were twice more likely to have a relapse than adherent patients (20% vs. 9%; adjusted odds ratio [aOR] 2.5; 95% CI 1.4-4.6). Other independent predictors of relapse were initial drug resistance to isoniazid and/or rifampicin (aOR 4.8; 95% CI 2.0-11.6) and smoking (aOR 3.1; 95% CI 1.6-6.0). The relapse rate among non-smoking, treatment adherent patients with drug-sensitive organisms was 4.8%. CONCLUSIONS The relapse rate under the DOTS programme may be reduced by ensuring that patients take their treatment regularly and are counselled effectively about quitting smoking.