Community health workers improve contact tracing among immigrants with tuberculosis in Barcelona

BACKGROUND: The important increase in immigration during recent years has changed the epidemiology and control strategies for tuberculosis (TB) in many places. This study evaluates the effectiveness of intervention with community health workers (CHW) to improve contact tracing among immigrants. METHODS: The study included all TB cases detected by the Barcelona TB Program from 2000 to 2005 and compared a period without CHW intervention (2000-2002) to a period with CHW intervention (2003-2005). The influence on contact tracing of sex, age, hospital of diagnosis, district of residence, birthplace, HIV, homeless and CHW intervention was analysed by logistic regression. Odds ratio (OR) and 95% confidence intervals (CI) were calculated. RESULTS: 960 foreign born TB cases were detected, 388 in the intervention period. Contact tracing was performed on 65,7% of 201 smear-positive cases during the pre-intervention period compared to 81.6% of 152 smear-positive TB cases during the intervention period (p < 0.001). Risk factors associated with incomplete contact tracing of smear-positive index cases included being diagnosed in two hospitals without contact tracing TB unit (OR = 3.5; CI:1.4-8.9) and (OR = 4.6; CI:1.6-13.5) respectively, birth place in India-Pakistan (OR = 4.4; CI:1.9-10.3) or North Africa (OR = 4.3; CI:1.8-10.5), having an unknown residence (OR = 5.4; CI:1.6-18.0), being HIV-infected (OR = 6.1; CI:2.5-14.8) or homeless (OR = 3.3; CI:1.3-8.2), and the absence of CHW intervention (OR = 2.4; CI:1.3-4.3). CONCLUSIONS: The effectiveness of contact tracing for TB control in areas with high immigration can be improved by incorporating CHWs who act as translators, cultural mediators and facilitators who accompany cases and contacts through treatment and follow-up.