Relapse in pulmonary tuberculosis

Five hundred forty-three patients with bacteriologically confirmed pulmonary tuberculosis who successfully completed treatment were followed for 5 years to determine relapse rates and to see whether any factors could be said to predispose to relapse. Practically the entire treatment of these patients had been carried out in their homes. The cumulative relapse rate during a 5-year period was 11.60 per cent. Relapse rates were low during the first 2 years of follow-up. Of the various factors considered in the analysis, age, sex, initial extent of disease or cavitation, and presence of initial or emergent drug-resistant bacilli did not influence the relapse rate. Patients who achieved complete radiographic clearing at the time treatment was stopped and those who were regular in treatment had comparatively low relapse rates. Cured patients included in the study were asked to report at least once annually for a checkup, and immediately if they developed any symptoms suggestive of relapse. Only one fourth of the cases of relapse were detected during routine annual checkup; in the remaining cases, the patients attended ahead of the next due visit because of symptoms. This casts doubt on the utility of keeping cured patients under prolonged routine surveillance.