Missed opportunities for diagnosis and treatment in patients with TB symptoms: a systematic review

BACKGROUND: The identification of patients with symptoms is the foundation of facility-based TB screening and diagnosis, but underdiagnosis is common. We conducted this systematic review with the hypothesis that underdiagnosis is largely secondary to patient drop out along the diagnostic and care pathway. METHODS: We searched (up to 22 January 2019) MEDLINE, Embase, and Cinahl for studies investigating patient pathway to TB diagnosis and care at health facilities. We used Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) to assess risk of bias. We reported proportions of patients with symptoms at each stage of the pathway from symptom screening to treatment initiation. RESULTS: After screening 3,558 abstracts, we identified 16 eligible studies. None provided data addressing the full cascade of care from clinical presentation to treatment initiation in the same patient population. Symptom screening, the critical entry point for diagnosis of TB, was not done for 33-96% of participants with symptoms in the three studies that reported this outcome. The proportion of attendees with symptoms offered a diagnostic investigation (data available for 15 studies) was very low with a study level median of 38% (IQR 14-44, range 4-84) CONCLUSIONS: Inefficiencies of the TB symptom screen-based patient pathway are a major contributor to underdiagnosis of TB, reflecting inconsistent implementation of guidelines to ask all patients attending health facilities about respiratory symptoms and to offer diagnostic tests to all patients promptly once TB symptoms are identified. Better screening tools and interventions to improve the efficiency of TB screening and diagnosis pathways in health facilities are urgently needed.