Browsing by Author "Kagujje M"

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Breakthrough TB among people living with HIV on TB preventive therapy.
(2022-Dec-21) Nyangu S; Kagujje M; Mwaba I; Luhanga D; Hambwalula R; Maliko S; Mushili T; Mwamba E; Mulai M; Muyoyeta M
BACKGROUND: Zambia has an estimated TB incidence of 319/100,000 population and a HIV prevalence of 11.1%. In 2020, only 49% of new people living with HIV (PLHIV) received TB preventive therapy (TPT) in Zambia. Misconceptions about the reliability of symptom screening and drug resistance among people who develop TB while on TPT are barriers to TPT scale-up. We determined the incidence and predictors of breakthrough TB during TPT among PLHIV in Zambia. METHOD: This was a retrospective analysis of routine TPT programme data among PLHIV collected between October 2016 and October 2019 from select primary health facilities in Zambia. RESULTS: Of 48,581 PLHIV enrolled on TPT, 130 (0.3%) developed breakthrough TB during TPT. Of the 130, 90 client records were accessed. The median age of the breakthrough TB cases was 35 years; 68% were males. Overall, 96% of the breakthrough TB cases had been on antiretroviral therapy (ART) for ⩽3 months; 24% were symptomatic at the beginning of TPT, 22% were asymptomatic and others had missing data. Of the 130 breakthrough TB cases, 79% developed TB in the first month after TPT initiation. The median time to TB diagnosis was 10 days (IQR 4-16). CONCLUSION: Breakthrough TB during TPT is rare among PHLIV on ART, and very rare after the first month of TPT initiation. It should therefore not be a barrier to TPT scale-up.
Clinical diagnosis of TB: lessons on misdiagnosis and overdiagnosis.
(2025-Jun) Singini DS; Sanjase N; Kagujje M; Shatalimi J; Chisanga CP; Lupatali ZD; Phiri D; Tatila T; Olwit W; Kerkhoff AD; Muyoyeta M
Clinically diagnosed TB patients (n = 335) at two facilities in Lusaka, Zambia were re-evaluated within two weeks of diagnosis. This re-evaluation included sputum Xpert Ultra testing and expert reader interpretation of the chest x-rays (CXRs) used for initial diagnosis. Repeat Xpert Ultra detected TB in just 2.6% (n=6). Of the remaining patients (n=222), expert CXR re-interpretation classified 18.0% as normal; 36.0% as abnormal, consistent with TB; and 46.0% as abnormal, not consistent with TB. These findings suggest that clinical TB is frequently over diagnosed in those without detectable CXR abnormalities and misdiagnosed in those with abnormal CXRs: these abnormalities are likely due to other respiratory conditions. Such misdiagnosis leads to unnecessary treatment, failure to treat the true underlying condition and incorrect estimates of TB burden.
Costs and cost-effectiveness of a comprehensive tuberculosis case finding strategy in Zambia.
(2021) Jo Y; Kagujje M; Johnson K; Dowdy D; Hangoma P; Chiliukutu L; Muyoyeta M; Sohn H
INTRODUCTION: Active-case finding (ACF) programs have an important role in addressing case detection gaps and halting tuberculosis (TB) transmission. Evidence is limited on the cost-effectiveness of ACF interventions, particularly on how their value is impacted by different operational, epidemiological and patient care-seeking patterns. METHODS: We evaluated the costs and cost-effectiveness of a combined facility and community-based ACF intervention in Zambia that utilized mobile chest X-ray with computer-aided reading/interpretation software and laboratory-based Xpert MTB/RIF testing. Programmatic costs (in 2018 US dollars) were assessed from the health system perspective using prospectively collected cost and operational data. Cost-effectiveness of the ACF intervention was assessed as the incremental cost per TB death averted over a five-year time horizon using a multi-stage Markov state-transition model reflecting patient symptom-associated care-seeking and TB care under ACF compared to passive care. RESULTS: Over 18 months of field operations, the ACF intervention costed $435 to diagnose and initiate treatment for one person with TB. After accounting for patient symptom-associated care-seeking patterns in Zambia, we estimate that this one-time ACF intervention would incrementally diagnose 407 (7,207 versus 6,800) TB patients and avert 502 (611 versus 1,113) TB-associated deaths compared to the status quo (passive case finding), at an incremental cost of $2,284 per death averted over the next five-year period. HIV/TB mortality rate, patient symptom-associated care-seeking probabilities in the absence of ACF, and the costs of ACF patient screening were key drivers of cost-effectiveness. CONCLUSIONS: A one-time comprehensive ACF intervention simultaneously operating in public health clinics and corresponding catchment communities can have important medium-term impact on case-finding and be cost-effective in Zambia. The value of such interventions increases if targeted to populations with high HIV/TB mortality, substantial barriers (both behavioral and physical) to care-seeking exist, and when ACF interventions can optimize screening by achieving operational efficiency.
Cross-sectional assessment of tuberculosis and HIV prevalence in 13 correctional facilities in Zambia.
(2021-Sep-27) Kagujje M; Somwe P; Hatwiinda S; Bwalya J; Zgambo T; Thornicroft M; Bozzani FM; Moonga C; Muyoyeta M
OBJECTIVE: To determine the prevalence of tuberculosis (TB) and HIV in 13 Zambian correctional facilities. METHODS: Cross-sectional study. SETTING: 13 correctional facilities in seven of the 10 provinces in Zambia. PARTICIPANTS: All incarcerated individuals were eligible for TB and HIV screening and testing. Of the total study population of 9695 individuals, which represent 46.2% of total correctional population at the beginning of the study, 8267 and 8160 were screened for TB and HIV, respectively. INTERVENTIONS: TB and HIV screening and testing was done between July 2018 and February 2019. PRIMARY OUTCOME MEASURES: All forms of TB, bacteriologically confirmed TB, drug-resistant TB, HIV. RESULTS: Prevalence of all forms of TB and bacteriologically confirmed TB was 1599 (1340-1894) per 100 000 population and 1056 (847-1301) per 100 000 population, respectively. Among those with bacteriologically confirmed TB, 4.6% (1.3%-11.4%) had drug-resistant TB.There was no statistically significant difference in the prevalence of all forms of TB, bacteriologically confirmed TB and drug resistant TB between adults and juveniles: (p=0.82), (p=0.23), (p=0.68) respectively. Of the bacteriologically confirmed TB cases, 28.7% were asymptomatic. The prevalence of HIV was 14.3% (13.6%-15.1%). The prevalence of HIV among females was 1.8 times the prevalence of HIV among males (p=0.01). CONCLUSION: Compared with the study in 2011 which screened inmates representing 30% of the country's inmate population, then the prevalence of all forms of TB and HIV in correctional facilities has reduced by about 75% and 37.6%, respectively. However, compared with the general population, the prevalence of all forms of TB and HIV was 3.5 and 1.3 times higher, respectively. TB/HIV programmes in correctional facilities need further strengthening to include aspects of juvenile-specific TB programming and gender responsive HIV programming.
Diagnosed with TB in the era of COVID-19: patient perspectives in Zambia.
(2020-Dec-21) Mwamba C; Kerkhoff AD; Kagujje M; Lungu P; Muyoyeta M; Sharma A
INTRODUCTION: Delayed TB diagnosis and treatment perpetuate the high burden of TB-related morbidity and mortality in resource-constrained settings. We explored the potential of COVID-19 to further compromise TB care engagement in Zambia. METHODS: From April to May 2020, we purposefully selected 17 adults newly diagnosed with TB from three public health facilities in Lusaka, Zambia, for in-depth phone interviews. We conducted thematic analyses using a hybrid approach. RESULTS: The majority of participants were highly concerned about the impact of lockdowns on their financial security. Most were not worried about being diagnosed with COVID-19 when seeking care for their illness because they felt unwell prior to the outbreak; however, they were very worried about contracting COVID-19 during clinic visits. COVID-19 was perceived as a greater threat than TB as it is highly transmittable and there is no treatment for it, which provoked fear of social isolation and of death among participants in case they contracted it. Nonetheless, participants reported willingness to continue with TB medication and the clinic visits required to improve their health. CONCLUSION: The COVID-19 pandemic did not appear to deter care-seeking for TB by patients. However, messaging on TB in the era of COVID-19 must encourage timely care-seeking by informing people of infection control measures taken at health facilities.
Engagement of private health care facilities in TB management in Lusaka district of Zambia: lessons learned and achievements.
(2024-Mar-14) Hambwalula R; Kagujje M; Mwaba I; Musonda D; Singini D; Mutti L; Sanjase N; Kaumba PC; Ziko LM; Zimba KM; Kasese-Chanda P; Muyoyeta M
BACKGROUND: Globally, at least 3 million TB patients are missed every year. In Zambia, the TB treatment coverage increased from 66% in 2020 to 92% in 2022. Involvement of all levels of health care service delivery is critical to finding all the missing TB patients. METHODS: A survey was undertaken in 15 private facilities in Lusaka district of Zambia using a structured tool administered by project team and a district health team member. Data collected during the survey was analysed and results were used to determine the type of TB services that were offered as well as barriers and enablers to TB service provision. This was followed by a set of interventions that included; training and mentorship on active case finding and systematic TB screening, increased diagnostic capacity, provision of national recording and reporting tools and provision of TB medication through linkage with the National TB program (NTP). We report findings from the baseline survey and changes in presumptive TB identification and notification following interventions. RESULTS: Major barriers to TB service delivery were the high cost of TB diagnostic testing and treatment in facilities where services were not supported by the National TB program; the mean cost was 33 (SD 33) and 93 (SD 148) for GeneXpert testing and a full course of treatment respectively. Pre-intervention, presumptive TB identification appeared to increase monthly by 4 (P = 0.000, CI=[3.00-5.00]). The monthly trends of presumptive TB identification during the intervention period increased by 5.32 (P = 0.000, [CI 4.31-6.33. Pre-intervention, the notification of TB appeared to decrease every month by -4.0 (P = 0.114, CI=[-9.00-0.10]) followed by an immediate increase in notifications of 13.94 TB patients (P = 0.001, CI [6.51, 21.36] in the first month on intervention. The monthly trends of notification during the intervention period changed by 0.34 (P = 0.000 [CI 0.19-0.48]). Private facility contribution to TB notification increased from 3 to 7%. CONCLUSION: Engagement and inclusion of private health facilities in TB service provision through a systems strengthening approach can increase contribution to TB notification by private health facilities.
Evaluating InferVision's Computer-Aided Detection (CAD) algorithm for Tuberculosis (TB) screening, Lusaka, Zambia.
(2025) Somwe P; Maimbolwa M; Chiyenu K; Lumpa M; Kagujje M; Muyoyeta M
The objective of this study was to evaluate the diagnostic performance of InferRead DR Chest for tuberculosis (TB) screening in a high HIV and TB burden setting. The study assessed the performance of InferRead DR Chest using anonymized chest X-ray images from an active TB case finding study in Lusaka, Zambia, for individuals aged 15 and older. The Xpert MTB/RIF or MTB culture was the composite reference standard. Performance was evaluated using the Area Under the Receiver Operating Characteristic Curve (AUC), and a binary classification point was selected where the sensitivity aligned with the WHO target product profile for TB screening tools. Of the 1,890 chest X-ray images that met the inclusion criteria, 91.5% of participants reported at least one TB symptom. The median age was 38 years (IQR: 29-47), and 1,186 (62.8%) were male. From the study sample, 449 participants (23.8%) reported a history of previous TB, and 704 (37.2%) were HIV positive. Among the analyzed images, 289 (15.3%) were classified as TB positive based on the composite reference standard test results. The overall area under the curve (AUC) was 0.81 (95% CI: 0.78-0.83). Among individuals with a history of previous TB and those who were HIV positive, the AUCs were 0.71 (95% CI: 0.63-0.79) and 0.77 (95% CI: 0.72-0.82), respectively. At a sensitivity of 90.3% (95% CI: 86.3%-93.5%), InferRead DR Chest achieved a specificity of 39.2% (95% CI: 36.8%-41.7%) at TB score cut point of 0.12. InferRead DR Chest had acceptable performance in our population. Additional training and piloting of InferRead DR Chest in this population is recommended.
Interrupted time-series analysis of active case-finding for tuberculosis during the COVID-19 pandemic, Zambia.
(2022-Mar-01) Lungu PS; Kerkhoff AD; Muyoyeta M; Kasapo CC; Nyangu S; Kagujje M; Chimzizi R; Nyimbili S; Khunga M; Kasese-Chanda N; Musonda V; Tambatamba B; Kombe CM; Sakulanda C; Sampa K; Silumesii A; Malama K
OBJECTIVE: To evaluate the impact of the coronavirus disease 2019 (COVID-19) pandemic and the subsequent implementation of tuberculosis response measures on tuberculosis notifications in Zambia. METHODS: We used an interrupted time-series design to compare monthly tuberculosis notifications in Zambia before the pandemic (January 2019 to February 2020), after implementation of national pandemic mitigation measures (April 2020 to June 2020) and after response measures to improve tuberculosis detection (August 2020 to September 2021). The tuberculosis response included enhanced data surveillance, facility-based active case-finding and activities to generate demand for services. We used nationally aggregated, facility-level tuberculosis notification data for the analysis. FINDINGS: Pre-pandemic tuberculosis case notifications rose steadily from 2890 in January 2019 to 3337 in February 2020. After the start of the pandemic and mitigation measures, there was a -22% (95% confidence interval, CI: -24 to -19) immediate decline in notifications in April 2020. Larger immediate declines in notifications were seen among human immunodeficiency virus (HIV)-positive compared with HIV-negative individuals (-36%; 95% CI: -38 to -35; versus -12%; 95% CI: -17 to -6). Following roll-out of tuberculosis response measures in July 2020, notifications immediately increased by 45% (95% CI: 38 to 51) nationally and across all subgroups and provinces. The trend in notifications remained stable through September 2021, with similar numbers to the predicted number had the pandemic not occurred. CONCLUSION: Implementation of a coordinated public health response including active tuberculosis case-finding was associated with reversal of the adverse impact of the pandemic and mitigation measures. The gains were sustained throughout subsequent waves of the pandemic.
Knowledge, attitudes, and practices towards childhood tuberculosis among healthcare workers at two primary health facilities in Lusaka, Zambia.
(2024) Kaumba PC; Siameka D; Kagujje M; Chungu C; Nyangu S; Sanjase N; Maimbolwa MM; Shuma B; Chilukutu L; Muyoyeta M
BACKGROUND: Zambia is among the 30 high-burden countries for tuberculosis (TB), Human Immunodeficiency Virus (HIV)-associated TB, and multi-drug resistant/rifampicin resistant TB with over 5000 children developing TB every year. However, at least 32% of the estimated children remain undiagnosed. We assessed healthcare workers' (HCWs) knowledge, attitudes, and practices (KAP) towards childhood TB and the factors associated with good KAP towards childhood TB. METHODS: Data was collected at two primary healthcare facilities in Lusaka, Zambia from July to August 2020. Structured questionnaires were administered to HCWs that were selected through stratified random sampling. Descriptive analysis was done to determine KAP. A maximum knowledge, attitude, and practice scores for a participant were 44, 10, and 8 points respectively. The categorization as either "poor" or "good" KAP was determined based on the mean/ median. Logistic regression analysis was performed to assess the associations between participant characteristics and KAP at statistically significant level of 0.05%. RESULTS: Among the 237 respondents, majority were under 30 years old (63.7%) and were female (72.6%). Half of the participants (50.6%) were from the outpatient department (OPD) and antiretroviral therapy (ART) clinic, 109 (46.0) had been working at the facility for less than 1 year, 134 (56.5%) reported no previous training in TB. The median/mean KAP scores were 28 (IQR 24.0-31.0), 7 (IQR = 6.0-8.0) and 5 points (SD = 1.9) respectively. Of the participants, 43.5% (103/237) had good knowledge, 48.1% (114/237) had a good attitude, and 54.4% (129/237) had good practice scores on childhood TB. In the multivariate analysis, clinical officers and individuals with 1-5 years' work experience at the facility had higher odds, 2.61 (95% CI = 1.18-5.80, p = 0.018) and 3.09 (95% CI = 1.69-5.65, p = 0.001) of having good attitude respectively, and medical doctors had 0.17 lower odds (95% CI = 0.18-5.80, p = 0.018) of good childhood TB practice. Other participant characteristics didn't show a significant association with the scores. CONCLUSION: The study found suboptimal levels of knowledge, attitude, and practices regarding childhood TB among HCWs. Targeted programmatic support needs to be provided to address the above gaps.
Pathways to care and preferences for improving tuberculosis services among tuberculosis patients in Zambia: A discrete choice experiment.
(2021) Kerkhoff AD; Kagujje M; Nyangu S; Mateyo K; Sanjase N; Chilukutu L; Eshun-Wilson I; Geng EH; Havlir DV; Muyoyeta M
BACKGROUND: Delays in the diagnosis of tuberculosis (TB) contribute to a substantial proportion of TB-related mortality, especially among people living with HIV (PLHIV). We sought to characterize the diagnostic journey for HIV-positive and HIV-negative patients with a new TB diagnosis in Zambia, to understand drivers of delay, and characterize their preferences for service characteristics to inform improvements in TB services. METHODS: We assessed consecutive adults with newly microbiologically-confirmed TB at two public health treatment facilities in Lusaka, Zambia. We administered a survey to document critical intervals in the TB care pathway (time to initial care-seeking, diagnosis and treatment initiation), identify bottlenecks and their reasons. We quantified patient preferences for a range of characteristics of health services using a discrete choice experiment (DCE) that assessed 7 attributes (distance, wait times, hours of operation, confidentiality, sex of provider, testing incentive, TB test speed and notification method). RESULTS: Among 401 patients enrolled (median age of 34 years, 68.7% male, 46.6% HIV-positive), 60.9% and 39.1% were from a first-level and tertiary hospital, respectively. The median time from symptom onset to receipt of TB treatment was 5.0 weeks (IQR: 3.6-8.0) and was longer among HIV-positive patients seeking care at a tertiary hospital than HIV-negative patients (6.4 vs. 4.9 weeks, p = 0.002). The time from symptom onset to initial presentation for evaluation accounted for the majority of time until treatment initiation (median 3.0 weeks, IQR: 1.0-5.0)-an important minority of 11.0% of patients delayed care-seeking ≥8 weeks. The DCE found that patients strongly preferred same-day TB test results (relative importance, 37.2%), facilities close to home (18.0%), and facilities with short wait times (16.9%). Patients were willing to travel to a facility up to 7.6 kilometers further away in order to access same-day TB test results. Preferences for improving current TB services did not differ according to HIV status. CONCLUSIONS: Prolonged intervals from TB symptom onset to treatment initiation were common, especially among PLHIV, and were driven by delayed health-seeking. Addressing known barriers to timely diagnosis and incorporating patients' preferences into TB services, including same-day TB test results, may facilitate earlier TB care engagement in high burden settings.
Patient Preferences for Strategies to Improve Tuberculosis Diagnostic Services in Zambia.
(2022-Aug-01) Kerkhoff AD; Chilukutu L; Nyangu S; Kagujje M; Mateyo K; Sanjase N; Eshun-Wilson I; Geng EH; Havlir DV; Muyoyeta M
IMPORTANCE: Delayed engagement in tuberculosis (TB) services is associated with ongoing transmission and poor clinical outcomes. OBJECTIVE: To assess whether patients with TB have differential preferences for strategies to improve the public health reach of TB diagnostic services. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional study was undertaken in which a discrete choice experiment (DCE) was administered between September 18, 2019, and January 17, 2020, to 401 adults (>18 years of age) with microbiologically confirmed TB in Lusaka, Zambia. The DCE had 7 attributes with 2 to 3 levels per attribute related to TB service enhancements. Latent class analysis was used to identify segments of participants with unique preferences. Multiscenario simulations were used to estimate shares of preferences for different TB service improvement strategies. MAIN OUTCOMES AND MEASURES: The main outcomes were patient preference archetypes and estimated shares of preferences for different strategies to improve TB diagnostic services. Collected data were analyzed between January 3, 2022, to July 2, 2022. RESULTS: Among 326 adults with TB (median [IQR] age, 34 [27-42] years; 217 [66.8%] male; 158 [48.8%] HIV positive), 3 groups with distinct preferences for TB service improvements were identified. Group 1 (192 participants [58.9%]) preferred a facility that offered same-day TB test results, shorter wait times, and financial incentives for testing. Group 2 (83 participants [25.4%]) preferred a facility that provided same-day TB results, had greater privacy, and was closer to home. Group 3 (51 participants [15.6%]) had no strong preferences for service improvements and had negative preferences for receiving telephone-based TB test results. Groups 1 and 2 were more likely to report at least a 4-week delay in seeking health care for their current TB episode compared with group 3 (29 [51.3%] in group 1, 95 [35.8%] in group 2, and 10 [19.6%] in group 3; P < .001). Strategies to improve TB diagnostic services most preferred by all participants were same-day TB test results alone (shares of preference, 69.9%) and combined with a small financial testing incentive (shares of preference, 79.3%), shortened wait times (shares of preference, 76.1%), or greater privacy (shares of preference, 75.0%). However, the most preferred service improvement strategies differed substantially by group. CONCLUSIONS AND RELEVANCE: In this study, patients with TB had heterogenous preferences for TB diagnostic service improvements associated with differential health care-seeking behavior. Tailored strategies that incorporate features most valued by persons with undiagnosed TB, including same-day results, financial incentives, and greater privacy, may optimize reach by overcoming key barriers to timely TB care engagement.
Prevalence and interpretation of Xpert
(2022-Mar-21) Chilukutu L; Mwanza W; Kerkhoff AD; Somwe P; Kagujje M; Muyoyeta M
BACKGROUND: The "trace call" results on Xpert® Ultra indicates extremely low TB levels and may be difficult to interpret. The prevalence of trace results among presumptive TB patients in high TB-HIV infection settings is unknown, as is the significance of divergent "trace call" result interpretations. METHODS: Presumptive TB patients attending a public health facility in Lusaka, Zambia, were prospectively enrolled. Participants underwent several TB investigations, including sputum smear microscopy, Ultra testing, and culture. The diagnostic accuracy of Ultra (culture-based reference) and the number of patients recommended for TB treatment was assessed according to several different interpretation criteria for "trace call" results. RESULTS: Among the 740 participants, 78 (10.5%) were Ultra-positive and an additional 37 (5.0%) had a "trace call" result. The prevalence of trace results did not differ according to HIV status (5.3% vs. 4.8%) or prior TB status (5.6% vs. 4.9%). Differing interpretations of trace results had modest effects on Ultra's sensitivity (range 79.3-82.6%) and specificity (range 94.3-99.2%), but increased the number of patients recommended for treatment by up to 44.9%. CONCLUSIONS: Ultra trace results were common in this setting. The interpretation of trace results may substantially impact TB case yield.
Sensitivity and specificity of CRP and symptom screening as tuberculosis screening tools among HIV-positive and negative outpatients at a primary healthcare facility in Lusaka, Zambia: a prospective cross-sectional study.
(2023-Apr-18) Kagujje M; Mwanza W; Somwe P; Chilukutu L; Creswell J; Muyoyeta M
OBJECTIVES: To evaluate the performance of point-of-care C-reactive protein (CRP) as a screening tool for tuberculosis (TB) using a threshold of 10 mg/L in both people living with HIV (PLHIV) and HIV-negative individuals and compare it to symptom screening using a composite reference for bacteriological confirmation of TB. METHODS: Prospective cross-sectional study. SETTING: A primary healthcare facility in Lusaka, Zambia. PARTICIPANTS: Consecutive adults (≥18 years) presenting for routine outpatient healthcare were enrolled. Of the 816 individuals approached to participate in the study, 804 eligible consenting adults were enrolled into the study, of which 783 were included in the analysis. PRIMARY OUTCOME MEASURES: Sensitivity, specificity, positive predictive value and negative predictive value (NPV) of CRP and symptom screening. RESULTS: Overall, sensitivity of WHO-recommended four-symptom screen (W4SS) and CRP were 87.2% (80.0-92.5) and 86.6% (79.6-91.8) while specificity was 30.3% (26.7-34.1) and 34.8% (31.2-38.6), respectively. Among PLHIV, sensitivity of W4SS and CRP was 92.2% (81.1-97.8) and 94.8% (85.6-98.9) while specificity was 37.0% (31.3-43.0) and 27.5% (22.4-33.1), respectively. Among those with CD4≥350, the NPV for CRP was 100% (92.9-100). In the HIV negative, sensitivity of W4SS and CRP was 83.8% (73.4-91.3) and 80.3% (69.5-88.5) while specificity was 25.4% (20.9-30.2) and 40.5% (35.3-45.6), respectively. Parallel use of CRP and W4SS yielded a sensitivity and NPV of 100% (93.8-100) and 100% (91.6-100) among PLHIV and 93.3% (85.1-97.8) and 90.0% (78.2-96.7) among the HIV negatives, respectively. CONCLUSION: Sensitivity and specificity of CRP were similar to symptom screening in HIV-positive outpatients. Independent use of CRP offered limited additional benefit in the HIV negative. CRP can independently accurately rule out TB in PLHIV with CD4≥350. Parallel use of CRP and W4SS improves sensitivity irrespective of HIV status and can accurately rule out TB in PLHIV, irrespective of CD4 count.
The Performance of Computer-Aided Detection Digital Chest X-ray Reading Technologies for Triage of Active Tuberculosis Among Persons With a History of Previous Tuberculosis.
(2023-Feb-08) Kagujje M; Kerkhoff AD; Nteeni M; Dunn I; Mateyo K; Muyoyeta M
BACKGROUND: Digital chest X-ray (dCXR) computer-aided detection (CAD) technology uses lung shape and texture analysis to determine the probability of tuberculosis (TB). However, many patients with previously treated TB have sequelae, which also distort lung shape and texture. We evaluated the diagnostic performance of 2 CAD systems for triage of active TB in patients with previously treated TB. METHODS: We conducted a retrospective analysis of data from a cross-sectional active TB case finding study. Participants ≥15 years, with ≥1 current TB symptom and complete data on history of previous TB, dCXR, and TB microbiological reference (Xpert MTB/RIF) were included. dCXRs were evaluated using CAD4TB (v.7.0) and qXR (v.3.0). We determined the diagnostic accuracy of both systems, overall and stratified by history of TB, using a single threshold for each system that achieved 90% sensitivity and maximized specificity in the overall population. RESULTS: Of 1884 participants, 452 (24.0%) had a history of previous TB. Prevalence of microbiologically confirmed TB among those with and without history of previous TB was 12.4% and 16.9%, respectively. Using CAD4TB, sensitivity and specificity were 89.3% (95% CI: 78.1-96.0%) and 24.0% (19.9-28.5%) and 90.5% (86.1-93.3%) and 60.3% (57.4-63.0%) among those with and without previous TB, respectively. Using qXR, sensitivity and specificity were 94.6% (95% CI: 85.1-98.9%) and 22.2% (18.2-26.6%) and 89.7% (85.1-93.2%) and 61.8% (58.9-64.5%) among those with and without previous TB, respectively. CONCLUSIONS: The performance of CAD systems as a TB triage tool is decreased among persons previously treated for TB.