Active case finding of sputum positive pulmonary tuberculosis in household contacts of tuberculosis patients in Karachi, Pakistan

Background: Pakistan holds rank 8 th among the world countries in which high prevalence of tuberculosis (TB) is present. There is evidenced that up to 30% of close contacts of TB patients become infected and at least half of them progress to active disease. The aim of this study was to screen active contacts of sputum positive pulmonary TB (SS +ve PTB) among household contacts (HHCs) of TB patients in Karachi, Pakistan. Materials and Methods: Cross-sectional study, which was conducted at chest clinics of Karachi. Total 750 HHCs were screened out of which 135 diagnosed smear positive TB patients was registered as index cases (ICs) from July 2012 till March 2013. Logistic regression analysis was carried out to estimate the odds ratio (OR) of different associated factors. Results: Prevalence among males (6.1%) compared with female (5.6%). The crude OR for age less than 15 years was 0.28 (95% confidence interval (CI) 0.14-0.55). Eighty-eight HHCs (11.73%) were found to have SS +ve TB. Disease frequency was significantly higher in HHCs who were smokers (adjusted OR 36.41; 95% CI 12.07, 109.79), had age less than 12 years (adjusted OR 3.63; 95% CI 1.68, 7.86), and who lived in houses less than 80 square yards (adjusted OR 3.77; 95% CI 1.27, 6.05). Conclusion: The IC with positive sputum smear constitutes great risk for TB infection and disease in HHC. There is needed for contact tracing strategy in the high-risk population.