Tuberculosis case finding and performance of symptom screening and rapid diagnostic tests in HIV-infected pregnant women in western Kenya
Tuberculosis (TB) during pregnancy in HIV-infected women is associated with poor maternal and infant outcomes. There are limited data on TB prevalence, optimal TB screening, and performance of rapid diagnostics in pregnant HIV-infected women.
We conducted a cross-sectional study among HIV-infected pregnant women seeking antenatal care in western Kenya. Following a standardized questionnaire, sputum smear microscopy for acid-fast bacilli (AFB), mycobacterial liquid culture, GeneXpert MTB/RIF (Xpert), urine lipoarabinomannan (LAM), and tuberculin skin testing (TST) were performed. We determined prevalence and correlates of culture-confirmed pulmonary TB, and compared diagnostic performance of World Health Organization (WHO) symptom screening and rapid diagnostic tests to sputum culture.
Between July 2013 and July 2014, we enrolled 306 women. Among 288 women with a valid sputum culture result, 54% were on antiretroviral treatment, median CD4 cell count was 437 cell/mm3 (IQR 342-565), and prevalence of culture-confirmed pulmonary TB was 2.4% (CI 1.0-4.9%). Cough >2 weeks (p=0.04) and positive TST (>5mm, p=0.03) were associated with pulmonary TB. Women with TB were 23-fold (95% CI 4.4-116.6) more likely to report a household member with TB symptoms (p=0.002). WHO symptom screen (43%), AFB smear (0%), Xpert (43%) and LAM (0%) had low sensitivity but high specificity (81%, 99%, 99% and 95%, respectively) for pulmonary TB.
HIV-infected pregnant women had appreciable prevalence of pulmonary TB despite modest immunosuppression. Current TB screening and diagnostic tools perform poorly in pregnant HIV-infected women. Adapted TB screening tools that include household member TB symptoms may be useful in this population.