Increased Risk of Incident Diabetes Among Individuals With Latent Tuberculosis Infection

OBJECTIVE: In cross-sectional US studies, patients with diabetes had twice the prevalence of latent TB infection (LTBI) compared to those without diabetes. However, whether LTBI contributes to diabetes risk is unknown. We used longitudinal data to determine if LTBI is associated with increased diabetes incidence. <p>RESEARCH DESIGN AND METHODS: We conducted a retrospective cohort study among US Veterans receiving care in the Veterans Health Administration 2000-2015. Eligibility included all patients without pre-existing diabetes who received a tuberculin skin test (TST) or interferon-gamma release-assay (IGRA). We excluded patients with a history of active TB and those diagnosed with diabetes before or within 2 years after LTBI testing. Patients were followed until diabetes diagnosis, death, or 2015. LTBI was defined as TST or IGRA positive. Incident diabetes was defined by use of ICD-9 codes in combination with a diabetes drug prescription. </p> <p>RESULTS: Among 574,113 eligible patients, 5.3% received both TST/IGRA, 79.1% received TST only, and 15.6% received IGRA only. Overall 6.6% had LTBI, and there were 2,535,149 person-years (PY) of follow-up after LTBI testing (median 3.2 years). The diabetes incidence rate (IR, per 100,000 PY) was greater in patients with LTBI compared to those without (1,012 vs 744; hazard ratio [HR] 1.4, 95%CI 1.3-1.4). Increased diabetes incidence persisted after adjustment for covariates (adjusted HR [aHR] 1.2, 95%CI 1.2-1.3) compared to those without LTBI. Among patients with LTBI, diabetes incidence was similar in those treated for LTBI compared to those who were not treated (aHR 1.0, 95%CI 0.9-1.1). </p> <p>CONCLUSION: Comprehensive longitudinal data indicate that LTBI is associated with increased diabetes incidence. These results have implications for people with LTBI, ~25% of the global population.</p>