title: Oral glucose tolerance test and HbA₁c for diagnosis of diabetes in patients undergoing coronary angiography: [corrected] the Silent Diabetes Study.
abstract: OBJECTIVE
  The primary aim of this study was to compare the results of HbA(1c) measurements with those of an OGTT for early diagnosis of 'silent diabetes' in patients with coronary artery disease (CAD) undergoing angiography without prediagnosed diabetes. A secondary aim was to investigate the correlation between the extent of CAD and the glycaemic status of the patient.
  
  
  METHODS
  Data from 1,015 patients admitted for acute (n = 149) or elective (n = 866) coronary angiography were analysed. Patients with known diabetes were excluded from the study. Using the OGTT results, patients were classified as having normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or diabetes. According to the results of the HbA(1c) measurements, patients were classified into three groups: normal (HbA(1c) <5.7% [<39 mmol/mol]), borderline (HbA(1c) 5.7-6.4% [39-47 mmol/mol]) and diabetes (HbA(1c) ≥6.5% [≥48 mmol/mol]).
  
  
  RESULTS
  Based on the OGTT, 513 patients (51%) were classified with NGT, 10 (1%) with IFG, 349 (34%) with IGT and 149 (14%) were diagnosed with diabetes. According to HbA(1c) measurements, 588 patients (58%) were classified as normal, 385 (38%) as borderline and 42 (4%) were diagnosed with diabetes. The proportion of patients with IGT and diabetes increased with the extent of CAD (IGT ρ = 0.14, p < 0.001, diabetes ρ = 0.09, p = 0.01). No differences in HbA(1c) were seen among the groups with different extents of CAD (p = 0.652).
  
  
  CONCLUSIONS
  An OGTT should be performed routinely for diagnosis of diabetes in patients with CAD undergoing coronary angiography, since HbA(1c) measurement alone appears to miss a substantial proportion of patients with silent diabetes. A limitation of the study is that the OGTT was not performed before the angiography.
authors.affiliation: Praxisklinik Herz und Gefaesse, Dresden, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Doerr
authors.forename: U
authors.initials: U
authors.lastname: Hoffmann
authors.forename: W
authors.initials: W
authors.lastname: Otter
authors.forename: L
authors.initials: L
authors.lastname: Heinemann
authors.forename: W
authors.initials: W
authors.lastname: Hunger-Battefeld
authors.forename: B
authors.initials: B
authors.lastname: Kulzer
authors.forename: A
authors.initials: A
authors.lastname: Klinge
authors.forename: V
authors.initials: V
authors.lastname: Lodwig
authors.forename: I
authors.initials: I
authors.lastname: Amann-Zalan
authors.forename: D
authors.initials: D
authors.lastname: Sturm
authors.forename: D
authors.initials: D
authors.lastname: Tschoepe
authors.forename: S G
authors.initials: SG
authors.lastname: Spitzer
authors.forename: J
authors.initials: J
authors.lastname: Stumpf
authors.forename: T
authors.initials: T
authors.lastname: Lohmann
authors.forename: O
authors.initials: O
authors.lastname: Schnell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D003925:Diabetic Angiopathies / Q000000981:diagnostic imaging*; D005260:Female; D005858:Germany / Q000453:epidemiology; D018149:Glucose Intolerance / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D015995:Prevalence; D012306:Risk; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human