A systematic review of active case-finding strategies for tuberculosis in homeless populations.

SETTING: Tuberculosis (TB) is prevalent in the homeless population, and can create health inequalities and challenges for eradication. Evidence-based approaches to active case finding (ACF) are needed.
OBJECTIVES: To determine the effectiveness of ACF for TB control, and identify strategies to improve uptake of screening and the diagnostic pathway in homeless populations in low- and medium-burden settings. Secondary objectives were to assess the yield of screening and participant characteristics.
DESIGN: A systematic search of electronic databases and grey literature sources identified ACF studies that reported population measures (prevalence or incidence) of TB control, and/or uptake and/or yield of screening for latent tuberculous infection (LTBI) or active TB affecting any site. Studies were described using narrative synthesis.
RESULTS: Twenty studies met the inclusion criteria. Studies were heterogeneous across multiple elements, including programme design, which likely contributed to variability in outcomes. ACF was associated with reductions in TB rates in three time-trend analyses. The strongest evidence for improving uptake of screening was for incentives, with mixed evidence for peer educators. At the observational level, professional support and mandatory screening may also improve uptake, and additional community support enhanced completion of the diagnostic pathway. Those most likely to be diagnosed with TB appeared less likely to accept screening. Yield of screening was 1.5-57% (41 684 participants) for LTBI, and 0-3.1% (91 771 participants) for active TB.
CONCLUSION: Observational evidence suggests that ACF is effective. Strategies to improve screening uptake were identified. Variability in uptake and yield necessitates programmes tailored to local populations; areas for further research were identified.