The impact, effectiveness and outcomes of targeted screening thresholds for programmatic latent TB infection testing in HIV: cohort study results.

Background: 

Screening and treatment for latent tuberculosis infection (LTBI) are key for TB control. In the UK, the National Institute of Health and Care Excellence (NICE) and the British HIV Association (BHIVA) give conflicting guidance on which groups of people living with HIV (PLWH) should be screened, and previous national analysis demonstrated heterogeneity in how guidance is applied. There is an urgent need for a firmer clinical effectiveness evidence base on which to build screening policy.

Methods: 

We conducted a systematic, programmatic LTBI screening intervention for all PLWH receiving care in Leicester, UK. We compared yields (percentage IGRA positive) and number of tests required when applying the NICE and BHIVA testing strategies, as well as strategies targeting screening by TB incidence in patients’ countries of birth.

Results: 

Of 1053 PLWH tested, 118 were IGRA-positive (11.2%). Positivity was associated with higher TB incidence in country-of-birth (adjusted odds ratio, 50–149 cases compared to <50 cases/100,000: 11.6 (95%CI 4.79–28.10)). There was high testing uptake (1053/1069, 98.5%). Appropriate chemoprophylaxis was commenced in 100/117 (85.5%) patients diagnosed with LTBI, of whom 96/100 (96.0%) completed treatment. Delivering targeted testing to PLWH from countries with TB incidence >150/100,000 or any sub-Saharan African country, would have correctly identified 89·8% of all LTBI cases while cutting tests required by 46·1% compared to NICE guidance, performing as well as BHIVA 2018 guidance.

Conclusions: 

Targeting screening to higher-risk PLWH increases yield and reduces the number requiring testing. Our proposed ‘PLWH-LTBI streamlined guidance’ offers a simplified approach, with the potential to improve national LTBI screening implementation.