Fragmentation of Healthcare Services as a Possible Determinant of the Low Completion for the Tuberculosis Cascade of Prevention among Asylum Seekers: Results from a Prospective Study with Historical Comparison

Background: Effective screening for tuberculosis infection (TBI) among asylum seekers (AS) is crucial for tuberculosis (TB) elimination in low incidence countries. Methods: We assessed the proportion of completion of the screening for TBI among asylum seekers with a centralized delivery method compared to the decentralized model previously adopted in the study area (historical control). In the historical model (January 2017 to May 2018) screening of AS was performed at the arrival offering TBI testing (TST followed by IGRA among those positive), radiological investigation, treatment initiation and hospital referral, if needed, at three sites: migrant health clinic, pneumology clinic and infectious diseases department for active disease (decentralized model). In the study model (June 2018, centralized) all steps of screening were performed at a single site, at a minimum of 6 months after arrival. Multivariable Poisson regression analysis, with robust variance, was used to assess variables associated with the completion of screening for infection. Multivariable logistic regression was used to identify factors associated with the diagnosis of TB infection. Results: The intervention approach was offered to 144 AS with an overall 98.6% proportion of completion (98.7% for those with a positive TST). In the historical screening model, 1192 AS were candidates for screening, which was completed by 74.5% of those who started it (44.7% for those resulted TST positive). Major losses (55%) were detected in the TST/CXR-IGRA sequential step, followed by the execution of TST test (25%). The ratio of screening completion was significantly higher in the intervention period (aIRR 1.78, 95% CI 1.68-1.88) and for AS coming from high incidence TB countries (aIRR 1.14, 95% CI 1.04-1.25). Screening after 6 months from arrival and age were associated with TB infection (2.09, 95% CI 1.36-3.2 and 1.14, 95% CI 1.01-1.29). Conclusions: Screening for TBI can be improved by a centralized approach. Higher prevalence of TBI 6 months after arrival could reflect recent (either during travel or in Italy) acquisition of the infection.