An Assessment of the Efficacy of Tuberculosis Screening Tools Among Adults Visiting Opportunistic Infections Clinics in Hwange District 2022- 2023

Abstract

Tuberculosis is a leading infectious disease causing a high burden of morbidity and mortality worldwide, the greatest debilitating effects are felt among the high risk group of people living with HIV. The disease is the number one opportunistic infection in this group of people and over 200 000 people living with HIV succumb to the disease each year. Over 85% of PLHIV live in Sub Saharan Africa, where Zimbabwe is located. Early TB detection through screening is central to intensified case finding and infection control therefore reducing the morbidity and mortality associated with the disease. Despite the availability of various TB screening tools, TB case detection remains poor. The TB case detection gap of about 44% reported in Zimbabwe in the year 2021 raises concern over the efficacy of the available screening tools and the methods being used for TB case finding. The WHO END TB strategy requires more than 90% case detection to combat Tuberculosis. Increased TB case detection needs screening tools that are highly sensitive and specific, meeting the targeted 90% sensitivity and 70% specificity. The performance of the screening tools in use in Zimbabwe needs evaluation to find the root cause of the case detection gap. The purpose of the study was to evaluate the efficacy of tuberculosis screening tools used among people living with HIV visiting opportunistic infections clinics in Hwange district, one of the remote districts with a high TB burden in the country. The study was a cross sectional study conducted for the period January 2022 to December 2023. Secondary data on TB screening was collected from the TB registers, O.I clinic attendance registers and presumptive TB registers to determine the number of people screened for TB, their screen outcomes and TB diagnostic outcomes on the gene xpert test for those who screened positive. All the data was captured and stored in Microsoft excel. Data presentation, analysis and processing was done using Stata software version 13. A total of 8 162 participants were screened for TB during the mentioned period. 2 256 participants with positive screen results were included in the study. 2119 participants screened positive on the symptom screening only, 45 screened positive on the CXR only and 92 participants screened positive on both CXR and symptom screening. Among these, 80 people were diagnosed with TB. The calculated sensitivity for symptom screening was 76.0% whilst specificity was 31.0%. The CXR had a sensitivity of 93.0% and specificity of 83.0%. Combining the screening tools had a sensitivity of 100.0% and specificity of 29.0%. Overall, the symptom screening tool had sub-optimal performance when compared to the WHO target profile for an efficacious screening tool. CXR performed better and met the required target profile for a screening tool. Combining the tools when screening for TB can increase case detection but there is need to resuscitate x-ray services and possibly upscale to computer aided detection of TB in Hwange if the set targets for the END TB strategy are to be achieved.