Latent tuberculosis infection testing in a large integrated healthcare system

Abstract

PurposeTuberculosis (TB) is a public health threat with >80% of active TB in the United States 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, particularly as it relates to LTBI test positivity, is needed. MethodsThis study, conducted between 01/01/2008 and 12/31/2019 at Kaiser Permanente Southern California, included individuals aged ≥18years without history of active TB. We examined factors associated with LTBI testing and LTBI positivity. ResultsAmong 3,816,884 adults (52% female, 37% White, mean age 43.5years [SD 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 odds of testing positive included male sex (OR:1.32, 95% CI:1.30–1.35), Asian/Pacific Islanders (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 TB endemic country (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 (Fig. 1). ConclusionsWe identified a mismatch between populations tested for LTBI and populations testing positive. Current LTBI testing practices may be missing individuals at high risk of LTBI. Additional work is needed to develop and implement screening guidelines that appropriately target testing for those at highest risk for LTBI.