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Active and passive case-finding in tuberculosis-affected households in Peru: a 10-year prospective cohort study

Saunders, MJ; Tovar, MA; Collier, D; Baldwin, MR; Montoya, R; Valencia, TR; Gilman, RH; (2019) Active and passive case-finding in tuberculosis-affected households in Peru: a 10-year prospective cohort study. The Lancet Infectious Diseases , 19 (5) pp. 519-528. 10.1016/S1473-3099(18)30753-9. Green open access

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Abstract

Background Active case-finding among contacts of patients with tuberculosis is a global health priority, but the effects of active versus passive case-finding are poorly characterised. We assessed the contribution of active versus passive case-finding to tuberculosis detection among contacts and compared sex and disease characteristics between contacts diagnosed through these strategies. Methods In shanty towns in Callao, Peru, we identified index patients with tuberculosis and followed up contacts aged 15 years or older for tuberculosis. All patients and contacts were offered free programmatic active case-finding entailing sputum smear microscopy and clinical assessment. Additionally, all contacts were offered intensified active case-finding with sputum smear and culture testing monthly for 6 months and then once every 4 years. Passive case-finding at local health facilities was ongoing throughout follow-up. Findings Between Oct 23, 2002, and May 26, 2006, we identified 2666 contacts, who were followed up until March 1, 2016. Median follow-up was 10·0 years (IQR 7·5–11·0). 232 (9%) of 2666 contacts were diagnosed with tuberculosis. The 2-year cumulative risk of tuberculosis was 4·6% (95% CI 3·5–5·5), and overall incidence was 0·98 cases (95% CI 0·86–1·10) per 100 person-years. 53 (23%) of 232 contacts with tuberculosis were diagnosed through active case-finding and 179 (77%) were identified through passive case-finding. During the first 6 months of the study, 23 (45%) of 51 contacts were diagnosed through active case-finding and 28 (55%) were identified through passive case-finding. Contacts diagnosed through active versus passive case-finding were more frequently female (36 [68%] of 53 vs 85 [47%] of 179; p=0·009), had a symptom duration of less than 15 days (nine [25%] of 36 vs ten [8%] of 127; p=0·03), and were more likely to be sputum smear-negative (33 [62%] of 53 vs 62 [35%] of 179; p=0·0003). InterpretationAlthough active case-finding made an important contribution to tuberculosis detection among contacts, passive case-finding detected most of the tuberculosis burden. Compared with passive case-finding, active case-finding was equitable, helped to diagnose tuberculosis earlier and usually before a positive result on sputum smear microscopy, and showed a high burden of undetected tuberculosis among women.

Type: Article
Title: Active and passive case-finding in tuberculosis-affected households in Peru: a 10-year prospective cohort study
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/S1473-3099(18)30753-9
Publisher version: https://doi.org/10.1016/S1473-3099(18)30753-9
Language: English
Additional information: This is an Open Access article under the CC BY 4.0 license. https://creativecommons.org/licenses/by/4.0/
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Infection and Immunity
URI: https://discovery.ucl.ac.uk/id/eprint/10077846
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