Browsing by Author "Mwanza W"

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Active TB case finding in a high burden setting; comparison of community and facility-based strategies in Lusaka, Zambia.
(2020) Kagujje M; Chilukutu L; Somwe P; Mutale J; Chiyenu K; Lumpa M; Mwanza W; Muyoyeta M; Strategic Information Department, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Tuberculosis Department, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
INTRODUCTION: We conducted an implementation science study to increase TB case detection through a combination of interventions at health facility and community levels. We determined the impact of the study in terms of additional cases detected and notification rate and compared the yield of bacteriologically confirmed TB of facility based and community based case finding. METHODOLOGY: Over a period of 18 months, similar case finding activities were conducted at George health facility in Lusaka Zambia and its catchment community, an informal peri-urban settlement. Activities included awareness and demand creation activities, TB screening with digital chest x-ray or symptom screening, sputum evaluation using geneXpert MTB/RIF, TB diagnosis and linkage to treatment. RESULTS: A total of 18,194 individuals were screened of which 9,846 (54.1%) were screened at the facility and 8,348 (45.9%) were screened in the community. The total number of TB cases diagnosed during the intervention period were 1,026, compared to 759 in the pre-intervention period; an additional 267 TB cases were diagnosed. Of the 563 bacteriologically confirmed TB cases diagnosed under the study, 515/563 (91.5%) and 48/563 (8.5%) were identified at the facility and in the community respectively (P<0.0001). The TB notification rate increased from 246 per 100,000 population pre-intervention to 395 per 100,000 population in the last year of the intervention. CONCLUSIONS: Facility active case finding was more effective in detecting TB cases than community active case finding. Strengthening health systems to appropriately identify and evaluate patients for TB needs to be optimised in high burden settings. At a minimum, provider initiated TB symptom screening with completion of the TB screening and diagnostic cascade should be provided at the health facility in high burden settings. Community screening needs to be systematic and targeted at high risk groups and communities with access barriers.
Prevalence and interpretation of Xpert
(2022-Mar-21) Chilukutu L; Mwanza W; Kerkhoff AD; Somwe P; Kagujje M; Muyoyeta M; Centre for Infectious Disease Research in Zambia, TB Department, Lusaka Zambia.; Division of HIV, Infectious Diseases and Global Medicine Zuckerberg San Francisco General Hospital and Trauma Center University of California, San Francisco, San Francisco, CA, USA.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
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; Strategic Information Department, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Tuberculosis Department, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Innovations and Grants, Stop TB Partnership, Geneva, Switzerland.; Tuberculosis Department, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia mkagujje@gmail.com.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
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.