Coverage and yield of tuberculosis contact investigations in the Netherlands

SETTING: An increasing proportion of tuberculosis (TB) patients in low-incidence countries are immigrants. It is unclear whether contact investigations among immigrant patients are adequate. OBJECTIVE: To determine whether ethnicity of pulmonary TB patients was associated with coverage and yield of contact investigations in the Netherlands. DESIGN: Contact investigation results were extracted from records of patients reported in the nationwide surveillance register in 2006 and 2007. Prevalence odds ratios (PORs) with 95% confidence intervals (CIs) were calculated to determine the association between patient ethnicity and coverage of contact investigations and the yield of individuals with Mycobacterium tuberculosis infection or TB. RESULTS: Of the 1040 pulmonary TB patients reported, 642 (62%) were eligible for analysis. Compared to close contacts of Dutch patients, close contacts of immigrant patients were significantly less likely to be examined for TB (89% vs. 93%, POR 0.6, 95%CI 0.5-0.7) and infection (50% vs. 75%, POR 0.3, 95%CI 0.3-0.4), whereas the yield was significantly higher for disease (1.5% vs. 0.4%, POR 3.4, 95%CI 1.8-6.4) and infection (13% vs. 10%, POR 1.2, 95%CI 1.0-1.5). CONCLUSION: The effectiveness of contact investigations in the Netherlands can be optimised by expanding the investigation of contacts of immigrant patients.