Estimated impact of timely, guideline-adherent tuberculosis screening in primary care settings among new permanent residents to British Columbia, Canada: A population-based study.

Abstract

Objectives: In Canada, most tuberculosis diagnoses occur among people previously residing in tuberculosis-endemic regions, due to progression of infection acquired prior to arrival. National guidelines recommend screening people with medical risk factors, known exposure, or specific demographic characteristics. The best strategy to reach this latter group remains uncertain, though primary care may serve as a promising entry point. We aimed to (1) describe primary care use among new permanent residents to British Columbia and (2) estimate the proportion of tuberculosis potentially preventable under a hypothetical primary care-based demographic screening policy.

Methods: We conducted a retrospective, population-based study of permanent residents to British Columbia (2000-2020) using linked administrative data. We measured time to first primary care visit and assessed tuberculosis preventability among those eligible for demographic-based screening (≤ 65 years from countries with tuberculosis incidence ≥ 200 per 100,000 within 5 years of arrival). Tuberculosis was considered potentially preventable if diagnosed ≥ 12 months after first primary care visit.

Results: Among 845,821 new permanent residents, 708,813 (83.8%) accessed primary care (median months, 15) and 286,337 (33.9%) met the demographic screening criteria. During follow-up, 1315 (0.2%) were diagnosed with tuberculosis (median months to diagnosis, 48.8). Of these, 859 (65.3%) met demographic screening criteria and a primary care screening model could have potentially prevented 420 (48.9%) of these events, equivalent to one-third of all diagnoses in the cohort.

Conclusion: Timely, demographic-based screening in primary care could have potentially prevented one-third of tuberculosis diagnoses. Strengthening engagement and reducing access barriers will be essential to support tuberculosis elimination.