Evaluation of the Latent Tuberculosis Care Cascade Among Public Health Clinics in the United States

Background Tuberculosis (TB) elimination within the United States (US) will require scaling up TB preventive services. Many public health departments offer care for latent tuberculosis infection (LTBI), though gaps in the LTBI care cascade are not well quantified. An understanding of these gaps will be required to design targeted public health interventions. Methods We conducted a cohort study through the Tuberculosis Epidemiologic Studies Consortium (TBESC) within 15 local health department (LHD) TB clinics across the US. Data was abstracted on individuals receiving LTBI care during 2016–2017 through chart review. Our primary objective was to quantify the LTBI care cascade, beginning with LTBI testing and extending through treatment completion. Results Among 23,885 participants tested by LHDs, 46% (11,009) were male with a median age of 31 (IQR 20–46). A median of 35% of participants were US-born at each site (IQR 11–78). Overall, 16,689 (70%) received a tuberculin skin test (TST), 6,993 (29%) received a Quantiferon (QFT), and 1,934 (8%) received a T-SPOT.TB; 5% (1,190) had more than one test. Among those tested, 2,877 (12%) had at least one positive test result (3% among US-born, and 23% among non-US–born, p<0.01). Of 2,515 (11%) of the total participants diagnosed with LTBI, 1,073 (42%) initiated therapy, of whom 817 (76%) completed treatment (32% of those with LTBI diagnosis). Conclusions Significant gaps were identified along the LTBI care cascade, with less than half of individuals diagnosed with LTBI initiating therapy. Further research is needed to better characterize the factors impeding LTBI diagnosis, treatment initiation, and treatment completion.