Computer Aided Screening for Tuberculosis in Low Resource Environments

People living with HIV (PLHIV) who require admission to hospital in WHO Africa region have poor outcomes. TB is very common in this group, but can be difficult to diagnose. The CASTLE trial aims to determine whether systematic screening for tuberculosis using digital chest X-ray with computer-aided diagnosis (DCXR-CAD) plus urine lipoarabinomannan testing with Fujifilm SILVAMP TB LAM (FujiLAM) plus usual care can improve admission outcomes for hospitalised PLHIV, compared to usual care alone. Our study is a single centre, unblinded, cluster-randomised (by day of admission) trial of DCXR-CAD plus FujiLAM plus usual care vs. usual care alone for screening for TB in unselected adult PLHIV admitted to a district general hospital in Malawi. The primary outcome is the proportion of people starting TB treatment by the time of death or hospital discharge. The secondary outcomes are all-cause mortality at 56 days from enrolment, proportion of people starting TB treatment within 24 hours from enrolment, and proportion of people with undiagnosed TB. In the CASTLE study we collect a single sputum sample for M. tb culture from participants and undiagnosed TB specifically refers to a person who did not start TB treatment by the time of death or discharge from hospital and has a M. tb cultured from their sputum sample. Alongside the two trial arms, a third smaller diagnostic cohort arm (1 in 9 of admission days / trial clusters) will explore the range of underlying infectious pathology. The diagnostic cohort does not contribute to trial outcomes.

CASTLE is funded by Wellcome, grant reference 203905/Z/16/Z