This study will examine an enhanced protocol to systematically screen a cohort of 400 new HIV clinic enrollees for prevalence and 1-year incidence of tuberculosis (TB).
Zambia is a high burden country for both HIV and TB infection and HIV clinic enrollees are a high-risk group for active TB. Current Zambian Ministry of Health screening protocols are symptom-based even though active case-finding studies in HIV-infected populations have shown that symptoms are not always predictive of active TB. As a result, there may be a significant amount of un-diagnosed TB among HIV-infected Zambians even in the context of accessing HIV care. This study will examine an enhanced protocol to systematically screen a cohort of 400 new HIV clinic enrollees for prevalence and 1-year incidence of TB using symptoms, light and fluorescence microscopy, chest radiography and TB culture of sputum and extra-pulmonary fluids (when indicated). In addition, the sensitivity, specificity and cost-effectiveness of each diagnostic tool will be evaluated.
Study Type
OBSERVATIONAL
Enrollment
400
All enrollees will receive a comprehensive TB screening regardless of symptom presentation.
Kalingalinga HIV Care and Treatment Clinic
Lusaka, Zambia
Prevalence of undiagnosed TB in those with HIV.
Among the cohort of 400 new enrollees at the clinic, all will be tested for TB at the specified time points using enhanced TB screening. Initial diagnosis will use smear microscopy and culture. Chest X-ray will be performed on the second day of enrollment. Presumptive Diagnosis: As culture results will take several days or weeks to become available, a presumptive diagnosis will be made based on history and physical exam, symptoms, smear microscopy and chest radiography results. All patients who are smear-positive by at least one sample will be diagnosed with TB per national guidelines. Patients who are smear-negative or suspected of extra-pulmonary TB based on clinical or radiographic findings may be treated empirically for TB at the discretion of a clinical or medical officer. Sputum samples will also be sent for testing at the end of the study with the Xpert MTB/RIF assay.
Time frame: Enrollment screening visit
Incidence of TB in a cohort of HIV clinic patients screened as 'TB negative'.
To account for patients who are censored prior to 12 months of follow-up, the incidence of TB will be calculated as a rate. Each patient will contribute follow-up time until they are censored, are diagnosed with TB, or have been in the study for 12 months. Patients who were diagnosed with TB at enrollment will not be included.
Time frame: enrollment, 3, 6, 9 and 12 month visits.
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