Yield, Efficiency and Costs of Mass Screening Algorithms for Tuberculosis in Brazilian Prisons.


Tuberculosis is a major cause of morbidity and mortality among incarcerated populations globally. We performed mass tuberculosis screening in three prisons and assessed yield, efficiency, and costs associated with various screening algorithms.

In this prospective study in three with prisons in high tuberculosis burden countries Brazilian prisons, we found that testing all participants with sputum Xpert MTB/RIF was sensitive approach, while remaining cost-efficient. These results support use of Xpert MTB/RIF for mass screening in tuberculosis-endemic prisons.

Between 2017 and 2018, inmates from the three prisons in Brazil were screened for tuberculosis by symptom assessment, chest radiography, sputum testing by Xpert MTB/RIF 4th generation and culture. Chest radiographs were scored by an automated interpretation algorithm (CAD4TB) that was locally calibrated to establish a positivity threshold. Four diagnostic algorithms were evaluated. We assessed the yield (percent of total cases found) and efficiency (prevalence among those screened) for each algorithm. We performed unit costing to estimate the costs of each screening or diagnostic test and calculated the cost per case detected for each algorithm.

We screened 5,387 prisoners, of whom 214 (3.9%) were diagnosed with tuberculosis. Compared to other screening strategies initiated with radiography or chest symptoms, the trial of all participants with a single Xpert MTB / RIF sputum test detected 74% of all tuberculosis cases at a cost of $ 249. Performing Xpert MTB/RIF screening tests only on those with symptoms had a similar cost per case diagnosed (US$ 255) but missed as many cases (73 vs 54) as screening all inmates.

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