A Clinical Scoring Algorithm for Determination of the Risk of Tuberculosis in HIV-Infected Adults: A Cohort Study Performed at Ethiopian Health Centers

T T Balcha; S Skogmar; E Sturegård; T Schön; N Winqvist; A Reepalu; Z H Jemal; G Tibesso; J Björk; P Björkman

doi:10.1093/ofid/ofu095

A Clinical Scoring Algorithm for Determination of the Risk of Tuberculosis in HIV-Infected Adults: A Cohort Study Performed at Ethiopian Health Centers

Open Forum Infect Dis. 2014 Oct 10;1(3):ofu095. doi: 10.1093/ofid/ofu095. eCollection 2014 Dec.

Authors

T T Balcha¹, S Skogmar², E Sturegård³, T Schön⁴, N Winqvist⁵, A Reepalu², Z H Jemal⁶, G Tibesso⁷, J Björk⁸, P Björkman²

Affiliations

¹ Infectious Disease Research Unit, Department of Clinical Sciences Malmö , Lund University , Malmö , Sweden ; Ministry of Health , Addis Ababa , Ethiopia.
² Infectious Disease Research Unit, Department of Clinical Sciences Malmö , Lund University , Malmö , Sweden.
³ Clinical Microbiology Unit, Department of Laboratory Sciences , Lund University , Malmö
⁴ Department of Medical Microbiology, Faculty of Health Sciences , Linköping University ; Department of Clinical Microbiology and Infectious Diseases , Kalmar County Hospital.
⁵ Infectious Disease Research Unit, Department of Clinical Sciences Malmö , Lund University , Malmö , Sweden ; Regional Department of Infectious Disease Control and Prevention, Malmö , Sweden.
⁶ Oromia Regional Health Bureau.
⁷ International Center for AIDS Care and Treatment Programs-Ethiopia , Columbia University Mailman School of Public Health , Addis Ababa , Ethiopia.
⁸ Department of Laboratory Sciences , Lund University , Sweden.

Abstract

Background: The World Health Organization (WHO) tuberculosis (TB) symptom screening instrument (WHO-TB) can identify human immunodeficiency virus (HIV)-infected individuals at low risk of tuberculosis (TB); however, many patients report WHO-TB symptoms and require further TB investigations. We hypothesized that further clinical scoring could classify subjects with a positive WHO-TB screening result (WHO-TB(+)) for the likelihood of TB.

Methods: HIV-infected adults eligible to initiate antiretroviral therapy (ART) were recruited and prospectively followed at 5 Ethiopian health centers. Irrespective of symptoms, all participants underwent sputum bacteriological testing for TB. Symptoms, physical findings, hemoglobin, and CD4 cell count results were compared between subjects with and those without bacteriologically confirmed TB. Variables associated with TB in WHO-TB(+) individuals were used to construct a scoring algorithm with multiple logistic regression analysis.

Results: Among 812 participants, 137 (16.9%) had TB. One hundred fifty-nine persons (20%) had a negative WHO-TB screen, 10 of whom had TB (negative predictive value [NPV], 94% [95% confidence interval {CI}, 90%-97.5%]). For WHO-TB(+) subjects, the following variables were independently associated with TB, and were assigned 1 point each in the clinical scoring algorithm: cough, Karnofsky score ≤80, mid-upper arm circumference <20 cm, lymphadenopathy, and hemoglobin <10 g/dL. Among subjects with 0-1 points, 20 of 255 had TB (NPV, 92% [95% CI, 89%-95%]), vs 19 of 34 participants with ≥4 points (positive predictive value, 56% [95% CI, 39%-73%]). The use of WHO-TB alone identified 159 of 784 (20%) with a low risk of TB, vs 414 of 784 (53%) using WHO-TB followed by clinical scoring (P< .001). The difference in proportions of confirmed TB in these subsets was nonsignificant (6.3% vs 7.2%; P= .69).

Conclusions: Clinical scoring can further classify HIV-infected adults with positive WHO-TB screen to assess the risk of TB, and would reduce the number of patients in need of further TB investigations before starting ART.

Clinical trials registration: NCT01433796.

Keywords: Ethiopia; HIV; health center; scoring; tuberculosis.

Associated data

ClinicalTrials.gov/NCT01433796