Household contact investigation coverage and barriers among pulmonary tb index cases in bidar district, Karnataka: a Nikshay-based cross-sectional study

Background: This study aimed to assess household contact investigation (HCI) completion, contact examination, tuberculosis preventive treatment (TPT) initiation, and barriers to HCI implementation among pulmonary tuberculosis (TB) index cases in Bidar district, Karnataka. Methods: A cross-sectional programmatic study was conducted using Nikshay records of pulmonary TB cases registered from July to December 2025, supplemented by structured telephonic interviews from January to June 2026. Eligible index cases were approached consecutively. Descriptive statistics, tests of association, and binomial logistic regression were used for analysis. Results: Among 267 index cases, HCI was completed in 162 (60.7%), while 105 (39.3%) had no completed HCI. Of 418 household contacts identified among cases with completed HCI, 380 (90.9%) were examined. Although 147 contacts reportedly initiated TPT, 175 (65.5%) index cases reported no household contact initiating TPT. Among cases without completed HCI, the most frequently reported barriers were absence of a health-worker visit (65.7%) and fear/stigma (23.8%). HCI completion was not significantly associated with gender, residence, taluk, type of TB, or mode of detection. Conclusions: HCI completion was suboptimal in Bidar, despite high examination coverage among identified household contacts. The absence of health-worker visits and fear/stigma were prominent reported barriers. Strengthening health-worker-led contact investigation and stigma-reduction efforts may improve HCI implementation.