Latent tuberculosis infection among patients with type 2 diabetes mellitus

Background Although there is well-proved association between type 2 diabetes mellitus (T2DM) and active tuberculosis, factors involved in the association between T2DM and latent tuberculosis infection (LTBI) are scarcely known. Aim The aim of this study was to study the prevalence and risk factors of LTBI in a cohort of Egyptian adults with T2DM including studying the effect of oral hypoglycemic drugs on this prevalence. Patients and methods All patients with T2DM were recruited from Menoufia University Endocrinology outpatient clinic during the period from June to December 2018. Demographic and clinical data, serum glucose and glycosylated hemoglobin (HbA1c) level, and QuantiFERON-TB Gold In-Tube and tuberculin skin test were assessed. Results In all, 102 patients were recruited, according to the QuantiFERON test; 22 (21.6%) patients were diagnosed with LTBI. Their mean age was 54.91±8.85, mean T2DM duration was 9.82±6.54/year, mean HbA1c% was 10.29±1.59, which is significantly higher than patients without LTBI. Patients on metformin-containing regimens were only 18% (four of 22 cases) among the LTBI patients, and 89.7% of the whole patients with metformin-containing regimen were without LTBI. Multivariant regression showed that age (odds ratio=1.178, P=0.041) and HbA1c% (odds ratio=2.789, P=0.008) were strong predictors for LTBI. Conclusion LTBI is prevalent in patients with T2DM especially among those with older age, longer duration of diabetes mellitus, uncontrolled diabetes mellitus, and on nonmetformin regimens. Age and HbA1c are strong predictors of LTBI in T2DM patients.