Screening for active tuberculosis in high-risk groups

OBJECTIVE: To evaluate an active case-finding strategy among drug users (DUs), economically disadvantaged individuals and recent immigrants from hyperendemic countries, a population at high risk of developing tuberculosis (TB). METHODS: Retrospective, observational study carried out by the Tuberculosis Unit of the City of Barcelona from September 2009 to December 2012. All participants underwent chest X-ray and were screened for symptoms. RESULTS: Of 5982 participants screened, 30 TB cases were detected (total prevalence 0.5%): 26 were pulmonary, 8 were smear-positive and 2 were resistant to multiple drugs. Directly observed treatment was advised for 19 patients (63%). TB prevalence in the recent immigrants group was significantly greater (1.77%) than in all other groups studied: economically disadvantaged individuals 0.30% (RR 5.9, 95%CI 2.30-15.14); DUs 0.62% (RR 2.05, 95%CI 0.91-4.64), non-recent immigrants 0.41% (RR 4.31, 95%CI 1.68-11.4); and all native-born individuals 0.41% (RR 4.33, 95%CI 1.71-10.92). The rate was much greater than the estimated prevalence for the general population of the city (,20 cases/100 000 population). CONCLUSIONS: In high-risk groups, active case finding can be used as a public health intervention to detect a large number of TB cases.