title: Prevalence of diabetes mellitus in biopsy-positive giant cell arteritis.
abstract: BACKGROUND
  We tested the hypothesis that patients with diabetes mellitus (DM) develop biopsy-positive giant cell arteritis (GCA) significantly less frequently than nondiabetic patients.
  
  
  METHODS
  We compared the prevalence of DM in patients with positive temporal artery biopsy (TAB) with that in patients with negative TAB via a retrospective study of 215 patients who underwent TAB. Patients were classified as having biopsy-positive GCA if microscopic examination disclosed active or healed arteritis. Patients were classified as having DM if they had a diagnosis of diabetes in their medical history or were taking oral hypoglycemic medications and/or insulin at or before the time of biopsy. In addition, we performed a meta-analysis of 8 previously published articles with a total of 1,401 additional biopsy-proven cases of GCA in patients whose status was recorded as diabetic or nondiabetic.
  
  
  RESULTS
  Of 44 cases with biopsy-positive GCA in our patient cohort, only 4 (9.1%) were diabetic at or before the time of biopsy. Of 171 patients with negative TAB, 61 (35.7%) had DM (P = 0.0006). The prevalence of DM among recorded cases of biopsy-positive GCA ranged from 0% to 13.8% in the 8 studies included in our meta-analysis, with a combined frequency of 89 diabetic patients in a total of 1,401 cases (6.35%).
  
  
  CONCLUSIONS
  The low frequency of a positive TAB in diabetic GCA suspects should be considered when formulating an index of suspicion in the evaluation of patients with possible GCA. More research is needed to delineate the nature of the interaction between DM and GCA.
authors.affiliation: University of Oklahoma College of Medicine, Oklahoma City, OK, USA. JMatthews2@med.miami.edu
authors.forename: Jared L
authors.initials: JL
authors.lastname: Matthews
authors.forename: David N
authors.initials: DN
authors.lastname: Gilbert
authors.forename: Bradley K
authors.initials: BK
authors.lastname: Farris
authors.forename: R Michael
authors.initials: RM
authors.lastname: Siatkowski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D001706:Biopsy; D015331:Cohort Studies; D048909:Diabetes Complications / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology; D013700:Giant Cell Arteritis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D016017:Odds Ratio; D012189:Retrospective Studies; D013699:Temporal Arteries / Q000473:pathology