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.