title: Can HbA1c detect undiagnosed diabetes in acute medical hospital admissions?
abstract: OBJECTIVE
  To study hyperglycaemia in acute medical admissions to Irish regional hospital.
  
  
  METHODS
  From 2005 to 2007, 2061 white Caucasians, aged >18 years, were admitted by 1/7 physicians. Those with diabetes symptoms/complications but no previous record of hyperglycaemia (n=390), underwent OGTT with concurrent HbA1c in representative subgroup (n=148). Comparable data were obtained for 108 primary care patients at risk of diabetes.
  
  
  RESULTS
  Diabetes was diagnosed immediately by routine practice in 1% (22/2061) [aged 36 (26-61) years (median IQ range)/55% (12/22) male] with pre-existing diabetes/dysglycaemia present in 19% (390/2061) [69 (58-80) years/60% (235/390) male]. Possible diabetes symptoms/complications were identified in 19% [70 (59-79) years/57% (223/390) male] with their HbA1c similar to primary care patients [54 (46-61) years], 5.7 (5.3-6.0)%/39 (34-42)mmol/mol (n=148) vs 5.7 (5.4-6.1)%/39 (36-43)mmol/mol, p=0.35, but lower than those diagnosed on admission, 10.2 (7.4-13.3)%/88 (57-122)mmol/mol, p<0.001. Their fasting plasma glucose (FPG) was similar to primary care patients, 5.2 (4.8-5.7) vs 5.2 (4.8-5.9) mmol/L, p=0.65, but 2hPG higher, 9.0 (7.3-11.4) vs 5.5 (4.4-7.5), p<0.001. HbA1c identified diabetes in 10% (15/148) with 14 confirmed on OGTT but overall 32% (48/148) were in diabetic range on OGTT. The specificity of HbA1c in 2061 admissions was similar to primary care, 99% vs 96%, p=0.20, but sensitivity lower, 38% vs 93%, p<0.001 (63% on FPG/23% on 2hPG, p=0.037, in those with possible symptoms/complications).
  
  
  CONCLUSIONS
  HbA1c can play a diagnostic role in acute medicine as it diagnosed another 2% of admissions with diabetes but the discrepancy in sensitivity shows that it does not reflect transient/acute hyperglycaemia resulting from the acute medical event.
authors.affiliation: Diabetes Translational Research Group, Institute of Translational Medicine, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK; Division of Medical Sciences, University of Birmingham, Birmingham, UK. Electronic address: susan.manley@uhb.nhs.uk.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Manley
authors.affiliation: Waterford Institute of Technology, Waterford, Ireland.
authors.forename: Kathleen T
authors.initials: KT
authors.lastname: O'Brien
authors.affiliation: Department of General Practice, University College Cork, Cork, Ireland.
authors.forename: Diarmuid
authors.initials: D
authors.lastname: Quinlan
authors.affiliation: Diabetes Translational Research Group, Institute of Translational Medicine, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Round
authors.affiliation: Wellcome Trust Clinical Research Facility, Institute of Translational Medicine, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Nightingale
authors.affiliation: Waterford Institute of Technology, Waterford, Ireland.
authors.forename: Fauzi
authors.initials: F
authors.lastname: Ali
authors.affiliation: Department of Endocrinology and Diabetes, University Hospital Waterford, Waterford, Ireland.
authors.forename: Behram K
authors.initials: BK
authors.lastname: Durrani
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK; Portiuncula Hospital and Galway University Hospital, Galway, Ireland; National University of Ireland, (NUIG), Galway, Ireland.
authors.forename: Aaron
authors.initials: A
authors.lastname: Liew
authors.affiliation: Diabetes Research Group, Swansea University, Swansea, UK.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Luzio
authors.affiliation: Gloucester Retinopathy Research Group, Gloucestershire Hospitals NHS Foundation Trust, Cheltenham, UK.
authors.forename: Irene M
authors.initials: IM
authors.lastname: Stratton
authors.affiliation: Waterford Institute of Technology, Waterford, Ireland; Department of Endocrinology and Diabetes, University Hospital Waterford, Waterford, Ireland; School of Medicine, University College Cork, Cork, Ireland; Department of Epidemiology & Public Health, University College Cork, Cork, Ireland; College of Medicine, Swansea University, Swansea, UK.
authors.forename: Graham A
authors.initials: GA
authors.lastname: Roberts
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D003951:Diagnostic Errors; D004630:Emergencies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005215:Fasting / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis*; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D007494:Ireland / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin
keywords: Acute medicine; Diagnosis of diabetes; HbA(1c); Oral glucose tolerance test; Stress hyperglycaemia