Abstract
Tuberculosis (TB) contact investigation facilitates earlier TB diagnosis and initiation of preventive therapy, but little data exist about the quality of its implementation. We conducted a retrospective cohort study to evaluate processes of TB contact investigation for index TB patients diagnosed in Cali, Colombia, in 2017, including dropout at each stage and overall yield. We constructed multivariable models to identify predictors of completing 1) the baseline household visit and 2) a follow-up clinic visit for TB evaluation among referred contacts. Sixty-eight percent (759/1,120) of registered TB patients were eligible for contact investigation; 77% (582/759) received a household visit. Odds of completing a household visit were significantly lower among men (adjusted odds ratio [aOR]: 0.6; 95% CI: 0.4-0.9; P = 0.009) and patients living in Cali's western zone (aOR: 0.5; 95% CI: 0.3-0.8; P = 0.008). Among 1880 screened contacts, 31% (n = 582) met the criteria for clinic referral, 47% (n = 271) completed a clinic visit, and 85% (231/271) completed testing. After adjusting for clustering by index patient, odds of completing referral were higher among contacts with cough (aOR: 22; 95% CI: 7.1-66; P < 0.001) and contacts living in the western zone (aOR: 4.1; 95% CI: 1.2-15; P = 0.03). The cumulative probability of a symptomatic contact from an eligible household completing TB evaluation was only 28%. The yield of active TB patients among contacts was only 0.3% (5/1880). Only 16% (17/103) of children aged < 5 years and none of the eight persons living with HIV, reported preventive therapy initiation. Routine monitoring of process indicators may facilitate quality improvement to close gaps in contact tracing and increase yield.