Latent tuberculosis infection testing practices in a large U.S. integrated healthcare system.

PURPOSE:Tuberculosis (TB) is a public health threat with >80% of active TB in the U.S. occurring due to reactivation of latent tuberculosis infection (LTBI). We may be under-screening those with high risk for LTBI and over-testing those at lower risk. A better understanding of gaps in current LTBI testing practices in relation to LTBI test positivity is needed. METHODS:This study, conducted between 01/01/2008 and 12/31/2019 at Kaiser Permanente Southern California, included individuals ≥18 years of age without a history of active TB. We examined factors associated with LTBI testing and LTBI positivity. RESULTS:Among 3,816,884 adults (52% female, 37% White, 37% Hispanic, mean age 43.5 years [S.D. 16.1]), 706,367 (19%) were tested for LTBI, among whom 60,393 (9%) had ≥1 positive result. Among 1,211,971 individuals meeting ≥1 screening criteria for LTBI, 210,025 (17%) were tested for LTBI. Factors associated with higher adjusted odds (aOR) of testing positive included male sex [aOR: 1.32, 95% CI:1.30-1.35], Asian/Pacific Islander [2.78, 2.68-2.88], current smoking [1.24, 1.20-1.28], diabetes [1.13, 1.09-1.16], hepatitis B [1.45, 1.34-1.57], hepatitis C [1.54, 1.44-1.66], and birth in a country with an elevated TB rate [3.40, 3.31-3.49]). Despite being risk factors for testing positive for LTBI, none of these factors were associated with higher odds of LTBI testing. CONCLUSIONS:Current LTBI testing practices may be missing individuals at high risk of LTBI. Additional work is needed to refine and implement screening guidelines that appropriately target testing for those at highest risk for LTBI.