Use of a scoring strategy to determine clinical risk of progression and risk group-specific treatment adherence in subjects with latent tuberculosis infection

ABSTRACT Background Annual incidence of active tuberculosis (TB) cases has plateaued in the US from 2013-2015. Most cases are from reactivation of latent tuberculosis infection (LTBI). A likely contributor is suboptimal LTBI treatment completion rates in subjects at high risk of developing active TB. It is unknown whether these patients are adequately identified and treated under current standard of care. Methods In this study, we sought to retrospectively assess the utility of an online risk calculator (tstin3d.com) in determining probability of LTBI and defining the characteristics and treatment outcomes of Low: 0-<10%, Intermediate: 10-<50% and High: 50-100% risk groups of asymptomatic subjects with LTBI seen between 2010-2015. Results 51(41%), 46 (37%) and 28 (22%) subjects were in Low, Intermediate and High risk groups respectively. Tstin3d.com was useful in determining the probability of LTBI in tuberculin skin test positive US born subjects. Of 114 subjects with available treatment information, overall completion rate was 61% and rates of completion in Low (60%), Intermediate (63%) and High (57%) risk groups were equivalent. 75% subjects in the 3HP group completed treatment compared to 58% in the INH group. Provider documentation of important clinical risk factors was often incomplete. Logistic regression analysis showed no clear trends of treatment completion being associated with assessment of a risk factor. Conclusion These findings suggest tstin3d.com could be utilized in the US setting for risk stratification of patients with LTBI and select treatment based on risk. Current standard of care practice leads to subjects in all groups finishing treatment at equivalent rates.