UC San Diego

BACKGROUND: The objective of this study was to investigate timing and risk factors for discontinuation of short-course tuberculosis preventive therapy (TPT) comparing directly observed 3-month isoniazid/rifapentine (3HP) vs self-administered 4-month rifampin (4R). METHODS: This was a subanalysis of a 6-month health department cohort (2016-2017) of 993 latent tuberculosis infection (LTBI) patients initiating 3HP (20%) or 4R (80%). Time at risk of TPT discontinuation was compared across regimens. Risk factors were assessed using mixed-effects Cox models. RESULTS: Short-course TPT discontinuation was higher with 4R (31% vs 14%; P < .0001), though discontinuation timing was similar. Latino ethnicity (hazard ratio [HR], 1.80; 95% CI, 1.20-2.90) and adverse events (HR, 4.30; 95% CI, 2.60-7.30) increased 3HP discontinuation risk. Social-behavioral factors such as substance misuse (HR, 12.00; 95% CI, 2.20-69.00) and congregate living (HR, 21.00; 95% CI, 1.20-360.00) increased 4R discontinuation risk. CONCLUSIONS: TPT discontinuation differed by regimen, with distinct risk factors. Addressing social determinants of health within TPT programs is critical to enhance completion rates and reduce TB disease risk in marginalized populations.