Epidemiology of Tuberculosis in Immigrants in a Large City with Large-Scale Immigration (1991-2013)

Background The increase in immigration in Barcelona between 2000 and 2008 forced a reorganization of the control of tuberculosis (TB). TB clinical units (TBCU) were created and community health workers (CHW) were gradually included. Objective To understand trends in the incidence of TB among immigrants, their main characteristics and treatment compliance during the period 1991-2013. Design We conducted a cross-sectional population-based study of cases detected among immigrants by the Tuberculosis Program in Barcelona, Spain. Sociodemographic, clinical characteristics and risk factors were described. The annual incidence was calculated for various periods and geographical areas of origin. In the linear trend analysis, a p-value of <0.05 was considered statistically significant. Results We detected 3,284 cases. Incidence decreased from 144.8/100,000 inhabitants in 1991 to 53.4/100,000 in 2013. Individuals born in Pakistan-India-Bangladesh had the highest average annual incidence (675/100,000). In all, 2,156 cases (65.7%) were male. 2,272 (69.2%) had pulmonary TB, of which 48.2% were smear-positive. 33% of the cases (1,093) lived in the inner city. Contact tracing (CT) coverage in smear-positive individuals rose from 56.8% in 1991-1999 to 81.4% in 2000-2013 (p<0.01); this value was less than 50% in people from Africa and Eastern European countries. The case fatality rate was 3.6% overall and 9.8% among those born in high-income countries (p<0.01). The highest rate of treatment default (12.8%) was observed among cases from the Maghreb. The rate of successful treatment increased from 69.9% in 1991-1999 to 87.5% in 2000-2013 (p<0.01). Conclusion The incidence of TB in immigrants is decreasing in Barcelona. Organizational actions, such as incorporating CHWs and TBCUs, have been decisive for the observed improvements.