Department of Medicine, Edendale Hospital, Pietermaritzburg, 3216, South Africa; Department of Medicine, University of KwaZulu-Natal, Pretoria, South Africa; Department of Medicine, University of Cape Town, Cape Town, South Africa; Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa; Department of International Health and Epidemiology, Johns Hopkins Bloomberg, School of Public Health, Cape Town, South Africa; Department of International Medicine, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, United States; Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
Wilson, D., Department of Medicine, Edendale Hospital, Pietermaritzburg, 3216, South Africa, Department of Medicine, University of KwaZulu-Natal, Pretoria, South Africa; Mbhele, L., Department of Medicine, Edendale Hospital, Pietermaritzburg, 3216, South Africa; Badri, M., Department of Medicine, University of Cape Town, Cape Town, South Africa; Morroni, C., Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa; Nachega, J., Department of International Health and Epidemiology, Johns Hopkins Bloomberg, School of Public Health, Cape Town, South Africa, Department of International Medicine, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, United States, Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa; Chaisson, R.E., Department of International Health and Epidemiology, Johns Hopkins Bloomberg, School of Public Health, Cape Town, South Africa, Department of International Medicine, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, United States; Maartens, G., Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
BACKGROUND: Outcomes from the World Health Organization's (WHO's) recommendations for the diagnosis of smear-negative tuberculosis (SNTB) in high human immunodeficiency virus prevalence settings are unknown. METHODS: We retrospectively applied the WHO algorithm for SNTB without danger signs to a prospectively enrolled cohort of ambulatory adult SNTB suspects in KwaZulu-Natal, South Africa. Participants fulfilling specified criteria for SNTB started empiric anti-tuberculosis treatment; the rest of the cohort was observed. All were followed for 8 weeks. Confirmed TB was defined as positive culture or granulomata plus acid-fast bacilli on histology. RESULTS: In total, 221 participants retrospectively fulfilled the WHO ambulatory SNTB algorithm entry criteria. The diagnostic performance of the WHO algorithm was: positive predictive value 0.34 (95%CI 0.26-0.43), negative predictive value 0.86 (95%CI 0.76-0.92), positive likelihood ratio 1.43 (95%CI 1.34-1.48), negative likelihood ratio 0.46 (95%CI 0.38-0.56) and diagnostic odds 3.1 (95%CI 1.52-6.34). Losses to follow-up (n = 4), hospitalisations (n = 6) and deaths (n = 5) did not differ significantly in those who were and were not diagnosed with SNTB. CONCLUSIONS: The WHO ambulatory SNTB algorithm had a reasonably high negative predictive value but low positive predictive value. Mortality over an 8-week period was low in participants who met the entry criteria for the WHO algorithm. © 2011 The Union.