title: Latent tuberculosis in patients with diabetes mellitus: prevalence, progression and public health implications.
abstract: BACKGROUND
  Diabetes mellitus (DM) confers a higher risk for tuberculosis (TB). Yet, TB screening and chemoprophylaxis for latent TB infection (LTBI) in DM remains controversial. We conducted a cross-sectional study to elucidate LTBI prevalence and longitudinal follow-up to ascertain LTBI to active TB progression rate in DM.
  
  
  METHODS
  220 DM patients without previous TB from the outpatient diabetes clinic of the hospital were enrolled. T-Spot TB, tuberculin-skin-test (TST) and chest radiography (CXR) were performed. LTBI was defined by negative CXR with reactive T-Spot TB. Progression to active TB was confirmed by cross-checking against the TB registry.
  
  
  RESULTS
  The prevalence of LTBI was 28.2% (62/220) by reactive T-Spot. None progressed to active TB from 2007-2013. Multivariate analysis revealed that any co-morbidity (p=0.016) was positively associated while metformin (p=0.008) was negatively associated with LTBI.
  
  
  CONCLUSIONS
  Over a quarter of DM patients harbor LTBI. While the lack of demonstrable progression to active TB within the follow-up time frame up to this point does not unequivocally support a routine TB screening policy or anti-TB chemoprophylaxis for LTBI in a diabetic population for now, this preliminary evidence needs re-evaluation with longer follow-up of this enrolled cohort over the next decade.
authors.affiliation: Senior Consultant, Department of Endocrinology, Tan Tock Seng Hospital.
authors.forename: M K S
authors.initials: MK
authors.lastname: Leow
authors.affiliation: Consultant, Department of Endocrinology, Tan Tock Seng Hospital.
authors.forename: R
authors.initials: R
authors.lastname: Dalan
authors.affiliation: Senior Consultant, Tuberculosis Control Unit, Tan Tock Seng Hospital.
authors.forename: C B E
authors.initials: CB
authors.lastname: Chee
authors.affiliation: Associate Professor, Centre for Quantitative Medicine, Duke-NUS Graduate Medical School.
authors.forename: A
authors.initials: A
authors.lastname: Earnest
authors.affiliation: Consultant, Department of Endocrinology, Tan Tock Seng Hospital.
authors.forename: D E K
authors.initials: DE
authors.lastname: Chew
authors.affiliation: Consultant, Department of Endocrinology, Tan Tock Seng Hospital.
authors.forename: A W K
authors.initials: AW
authors.lastname: Tan
authors.affiliation: Senior Consultant, Department of Endocrinology, Tan Tock Seng Hospital.
authors.forename: W Y C
authors.initials: WY
authors.lastname: Kon
authors.affiliation: Senior Consultant, Department of Endocrinology, Tan Tock Seng Hospital.
authors.forename: M
authors.initials: M
authors.lastname: Jong
authors.affiliation: Senior Consultant, Clinical Microbiology, Laboratory Medicine, Tan Tock Seng Hospital.
authors.forename: T
authors.initials: T
authors.lastname: Barkham
authors.affiliation: Senior Consultant, Tuberculosis Control Unit, Tan Tock Seng Hospital.
authors.forename: Y T
authors.initials: YT
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000453:epidemiology* / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D055985:Latent Tuberculosis / Q000453:epidemiology* / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012042:Registries