A clinical scoring system to prioritise investigation for tuberculosis among adults attending HIV clinics in South Africa.

Hanifa, Y; Fielding, KL; Chihota, VN; Adonis, L; Charalambous, S; Foster, N; Karstaedt, A; McCarthy, K; Nicol, MP; Ndlovu, NT; Sinanovic, E; Sahid, F; Stevens, W; Vassall, A; Churchyard, GJ; Grant, AD; (2017) A clinical scoring system to prioritise investigation for tuberculosis among adults attending HIV clinics in South Africa. PLoS One, 12 (8). e0181519. ISSN 1932-6203 DOI: https://doi.org/10.1371/journal.pone.0181519

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The World Health Organization (WHO) recommendation for regular tuberculosis (TB) screening of HIV-positive individuals with Xpert MTB/RIF as the first diagnostic test has major resource implications. To develop a diagnostic prediction model for TB, for symptomatic adults attending for routine HIV care, to prioritise TB investigation. Cohort study exploring a TB testing algorithm. HIV clinics, South Africa. Representative sample of adult HIV clinic attendees; data from participants reporting ≥1 symptom on the WHO screening tool were split 50:50 to derive, then internally validate, a prediction model. TB, defined as "confirmed" if Xpert MTB/RIF, line probe assay or M. tuberculosis culture were positive; and "clinical" if TB treatment started without microbiological confirmation, within six months of enrolment. Overall, 79/2602 (3.0%) participants on ART fulfilled TB case definitions, compared to 65/906 (7.2%) pre-ART. Among 1133/3508 (32.3%) participants screening positive on the WHO tool, 1048 met inclusion criteria for this analysis: 52/515 (10.1%) in the derivation and 58/533 (10.9%) in the validation dataset had TB. Our final model comprised ART status (on ART > 3 months vs. pre-ART or ART < 3 months); body mass index (continuous); CD4 (continuous); number of WHO symptoms (1 vs. >1 symptom). We converted this to a clinical score, using clinically-relevant CD4 and BMI categories. A cut-off score of ≥3 identified those with TB with sensitivity and specificity of 91.8% and 34.3% respectively. If investigation was prioritised for individuals with score of ≥3, 68% (717/1048) symptomatic individuals would be tested, among whom the prevalence of TB would be 14.1% (101/717); 32% (331/1048) of tests would be avoided, but 3% (9/331) with TB would be missed amongst those not tested. Our clinical score may help prioritise TB investigation among symptomatic individuals.

Item Type: Article
Faculty and Department: Faculty of Infectious and Tropical Diseases > Dept of Clinical Research
Faculty of Epidemiology and Population Health > Dept of Infectious Disease Epidemiology
Faculty of Public Health and Policy > Dept of Global Health and Development
Research Centre: TB Centre
PubMed ID: 28771504
Web of Science ID: 406853600024
URI: http://researchonline.lshtm.ac.uk/id/eprint/4189932


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