Association between Self-Reported Diabetes Mellitus and Latent Tuberculosis Infection in a U.S.-Born Homeless Population

Background: Latent TB infection (LTBI) is disproportionately prevalent among certain US populations, including homeless persons.Diabetes mellitus (DM) is also more common among those with LTBI and suggests higher risk for development of TB disease.A significant association between LTBI and self-reported DM in homeless populations would support self-report as potentially useful to ascertain this important risk. Objectives: To evaluate associations between self-reported DM and LTBI among persons using night shelters in an urban Texas county. Methods: We analyzed data from U.S.-born persons using night shelters in Tarrant County, Texas during January 2013 to December 2016. Study data are a local subset of data collected by the Tuberculosis Epidemiologic Studies Consortium, a 10-site study funded by the Centers for Disease Control and Prevention to assess sensitivity and specificity of three commercially-available tests for LTBI: the tuberculin skin test and two interferon-gamma release blood assays: QuantiFERON®-TB Gold In-Tube, and T-SPOT®.TB test. We defined LTBI as a positive result on any test. Multiple logistic regression was used to evaluate relationships between LTBI and self-reported DM while controlling demographic and other factors. Results: Among 1,030 shelter users, we found no association between self-reported DM and LTBI (Odds ratio, 1.22; 95% confidence interval, 0.68 to 2.20). Conclusions: Diabetes is an important TB-related risk factor and its ascertainment can help prioritize targeted screening and intervention. We found self-reported DM did not effectively predict LTBI in our sample, suggesting it is an insufficiently reliable measurement for homeless screenings.