Performance of Clinical Screening Algorithms for Tuberculosis Intensified Case Finding among People Living with HIV in Western Kenya

Abstract

ObjectiveTo assess the performance of symptom-based screening for tuberculosis (TB), alone and with chest radiography among people living with HIV (PLHIV), including pregnant women, in Western Kenya.DesignProspective cohort studyMethodsPLHIV from 15 randomly-selected HIV clinics were screened with three clinical algorithms [World Health Organization (WHO), Ministry of Health (MOH), and “Improving Diagnosis of TB in HIV-infected persons” (ID-TB/HIV) study], underwent chest radiography (unless pregnant), and provided two or more sputum specimens for smear microscopy, liquid culture, and Xpert MTB/RIF. Performance of clinical screening was compared to laboratory results, controlling for the complex design of the survey.ResultsOverall, 738 (85.6%) of 862 PLHIV enrolled were included in the analysis. Estimated TB prevalence was 11.2% (95% CI, 9.9–12.7). Sensitivity of the three screening algorithms was similar [WHO, 74.1% (95% CI, 64.1–82.2); MOH, 77.5% (95% CI, 68.6–84.5); and ID-TB/HIV, 72.5% (95% CI, 60.9–81.7)]. Sensitivity of the WHO algorithm was significantly lower among HIV-infected pregnant women [28.2% (95% CI, 14.9–46.7)] compared to non-pregnant women [78.3% (95% CI, 67.3–86.4)] and men [77.2% (95% CI, 68.3–84.2)]. Chest radiography increased WHO algorithm sensitivity and negative predictive value to 90.9% (95% CI, 86.4–93.9) and 96.1% (95% CI, 94.4–97.3), respectively, among asymptomatic men and non-pregnant women.ConclusionsClinical screening missed approximately 25% of laboratory-confirmed TB cases among all PLHIV and more than 70% among HIV-infected pregnant women. National HIV programs should evaluate the feasibility of laboratory-based screening for TB, such as a single Xpert MTB/RIF test for all PLHIV, especially pregnant women, at enrollment in HIV services.

Cough Due to TB and Other Chronic Infections

“…Screening for any WHO-endorsed symptom rather than only cough increases the diagnostic sensitivity for TB. 10,[27][28][29][30][31][32] The presence of other WHOendorsed symptoms in addition to cough increases the likelihood that a patient has pulmonary TB, but it is still too low to confirm a diagnosis of pulmonary TB in resource-limited settings. However, the negative predictive value (ie, the absence of any WHO-endorsed symptom in PLWHIV in high-prevalence countries who are not receiving ART, not close contacts of active cases, and are not pregnant) can help to exclude those who do not require additional testing for pulmonary TB.…”

“…The WHOendorsed symptom screen sensitivity was only 28% in pregnant women with pulmonary TB. 30 Chest radiography, WHO-endorsed symptom screening, and sputum testing were planned for 825 PLWHIV in South Africa, and 737 who provided at least one sputum specimen were included. 31 Pulmonary TB was diagnosed in 31 of 522 (5.9%) receiving ART and 34 of 215 (15.8%) not receiving ART.…”

Effect of Pregnancy on Interferon Gamma Release Assay and Tuberculin Skin Test Detection of Latent TB Infection Among HIV-Infected Women in a High Burden Setting

“…[3, 4, 31] In a large cohort in the United Kingdom, there was a nearly 2-fold increased incidence of active TB in the early postpartum period. [3] Given difficulties with TB screening and diagnoses in pregnancy [18, 19], this early postpartum risk could reflect TB during pregnancy not detected until postpartum[3], or pregnancy-related risk of progression from infection to disease. In a cohort of HIV-infected women in Kenya, positive IGRA results in pregnancy were associated with increased postpartum active tuberculosis and mortality among mothers and their infants.…”

“…[16] Antenatal HIV prevalence estimates are 19–26%,[17] and the burden of culture-confirmed pulmonary TB among HIV-infected pregnant women in this setting is 2.4–5.9%. [18, 19] In Kenya, BCG administration is administered once at birth, and BCG coverage is high (79–99%). [20] At the time of this study, pregnant HIV-infected women were not routinely offered isoniazid prophylaxis.…”

Comparison of Mycobacterium tuberculosis complex Yield and Contamination Rates using Lowenstein-Jensen with and without Antibiotics in Western Kenya

“…We conducted a cross sectional study on sputum samples submitted from PLHIV as part of a TB intensified case finding study ("parent study") [21,22] The parent study recruited from 15 randomlyselected public HIV care and treatment facilities that had at least 200 enrolled patients in the Siaya, Bondo and Kisumu East Districts from the former Nyanza Province. Enrolment occurred in a phased manner between May 2011 and June 2012, with each clinical site enrolling participants for 10 weeks.…”