Prevalence of gene xpert mtb trace detected result and health workers’ perspectives on diagnosis and management at five health facilities in uganda

Abstract

Background: Xpert MTB/RIF Ultra is a cartridge-based rapid molecular assay, introduced in 2017 as an updated version of the Xpert MTB/RIF for tuberculosis (TB) diagnosis. Gene Xpert Ultra has sensitivity (88%) nearing that of sputum culture, for detecting the presence of Mycobacterium tuberculosis (MTB), due to an added result category of MTB trace detected, but specificity (96%) is not perfect. The results are often interpreted as an indication for TB treatment, but may also represent detection of nonviable bacilli or analytical errors. World Health Organization guidelines recommend interpreting most trace sputum results as bacteriologic confirmation of TB among HIV positive individuals, but to exercise clinical judgment in deciding to treat for pulmonary TB based on a trace result in HIV-negative adults, with no recent history of TB. We sought to assess the prevalence of Gene Xpert MTB Trace results, and health workers’ perspectives on the diagnosis and management of patients with MTB trace results at five health facilities in Uganda. Methods: This was a cross sectional study with a mixed methods data collection approach, to determine prevalence of MTB trace, and explore health worker perspectives on diagnosis and management of patients with MTB trace results, at five health facilities. Between 2019 and December 2021, we extracted patient level data from presumptive TB registers, Laboratory TB registers, Gene Xpert testing platforms, and the unit treatment registers, and entered the data into Research Electronic Data Capture (REDCap) Mobile software. Data extracted from the data sources included demographics, HIV status, Gene Xpert test results and date and treatment initiation status. We also interviewed health workers involved in TB evaluation and treatment for two or more years, to explore their perspectives on diagnosis and management of patients with MTB trace results. Descriptive statistics and multivariable regression analyses were used, to analyse quantitative data, using Stata version 15.1, and qualitative data were analysed using thematic analysis. Results: Of 18,617 patients registered at five health facilities, 17,337 (93.1%) were eligible. The median age was 34 years (IQR: 24 – 46) and 8,875 (51.2%) were male. People living with HIV were 6,092 (35.1%), and those with a history of TB were 645 (3.7%). The overall prevalence of MTB trace was 2.0% (353/18,617), 2.1% (129/6092) in People Living with HIV Disease (PLWH), and 2.0% (224/11021) in HIV negative people. Men (AOR=1.3; 95% CI: 1.05, 1.61; p=0.015) and individuals with past TB infection (AOR=9.3; 95% CI: 4.08, 20.98; p<0.001), were more likely to have MTB trace detected results. Of the 253 patients with trace results; 213 were treated for MTB. Of these, 77 were HIV- positive, and 136 were HIV- negative. A repeat test was done on 15 HIV negative patients with MTB Trace detected result, before initiation of TB treatment. Perceptions from interviews from health workers indicated that individuals with MTB Trace results should be treated as those with a diagnosis of TB and should be started on treatment. Five main themes were identified and these included: capability in interpreting MTB trace results, their awareness about MTB trace results, ability to communicate TB results to patients, and also indication for need of a more comprehensive training to improve their skills and knowledge for patient management. Conclusion: This study highlighted low burden of MTB trace detected results among presumptive patients at primary health care facilities in Uganda. Health workers know about MTB Trace as part of the result category when using Gene Xpert Ultra test, however there is need for additional training on TB guidelines for proper management of individuals with these results, for better patient outcome.