Oral Presentation Australian Diabetes Society and the Australian Diabetes Educators Association Annual Scientific Meeting 2014

Routine HbA1c measurement identifies undiagnosed diabetes in 20% of general medical inpatients with an HbA1c ≥ 6.5%: results of the Austin Health Diabetes Discovery Initiative  (#6)

Natalie Nanayakkara 1 , Hang Nguyen 2 , Nyuk Pang 1 , Oliver Piercey 3 , Sarah Romeo 3 , Matthew Stokes 3 , Danielle Richmond 3 , Michelle Lee 3 , Que Lam 4 , Graeme Hart 5 , Elizabeth Owen-Jones 6 , Victoria Stevenson 1 , Leonid Churilov 7 , Douglas Johnson 3 , Scott Baker 1 2 , Elif I Ekinci 1 8 9 , Jeffrey D Zajac 1 8
  1. Department of Endocrinology, Austin Health, Melbourne, Victoria, Australia
  2. Department of General Medicine , Austin Health, Melbourne, Victoria, Australia
  3. Department of General Medicine, Austin Health, Melbourne, Victoria, Australia
  4. Pathology Department, Austin Health, Melbourne, Victoria, Australia
  5. Department of Intensive Care, Austin Health, Melbourne, Victoria
  6. Department of Administrative Informatics, Austin Health, Melbourne, Victoria, Australia
  7. The Florey Institute of Neuroscience & Mental Health, Melbourne, Victoria, Australia
  8. Department of Medicine, University of Melbourne, Heidelberg, Victoria, Australia
  9. Menzies School of Health Research, Darwin, Northern Territory, Australia


While a high and rising prevalence of diabetes in acute inpatient settings is well recognised, up to 40% of inpatients with diabetes remain undiagnosed1. In hospital inpatients, including those admitted under general medicine, inpatient hyperglycaemia is associated with increased mortality and morbidity2,3.  HbA1c measurement is superior to diagnose diabetes in hospital inpatients as it is unaffected by factors such as stress hyperglycaemia and recent glucocorticoid use. The aims of this study were to investigate the prevalence and outcomes for patients with diagnosed and undiagnosed diabetes admitted to the general medicine ward.


Under the Diabetes Discovery Initiative and using the Cerner MillenniumÒ Health IT Platform, HbA1c testing was performed automatically for all patients aged ≥54 years admitted to Austin Health, a tertiary metropolitan hospital between June 2013 and January 2014.  Diabetes was diagnosed in patients with an HbA1c >=6.5%4. Clinical and demographic information was collected by examination of the medical records.


Over 35% (372/1072) of patients admitted under general medicine had an HbA1c >=6.5%.  Of these 372 patients (table 1), 72 (19%) had no prior history of diabetes and 76 (20%) had a prior history of diabetes and an HbA1c≥8.5%. While overall HbA1c level did not correlate with length of stay (LOS), in patients with HbA1c ≥8.5%, there was a correlation with length of stay (r=0.23, p=0.04), with each 1% rise in HbA1c corresponding to an increased LOS by 0.75 days. There were no significant differences between the two groups in the rates of intensive care unit admission and inpatient mortality. 


Undiagnosed diabetes affects nearly 20% of patients in patients admitted under general medicine with an HbA1c≥6.5.  Routine admission HbA1c measurement can identify patients with undiagnosed diabetes as well as patients with poor glycaemic control for review. Further study is required to determine if early identification and management of these patients improves patient outcomes.

Table 1: Characteristics of 372 patients with an admission HbA1c ≥6.5%.


  1. Wexler DJ, Nathan DM, Grant RW, Regan S, Van Leuvan AL, Cagliero E 2008 Prevalence of elevated hemoglobin A1c among patients admitted to the hospital without a diagnosis of diabetes. J Clin Endocrinol Metab 93:4238–4244
  2. Umpierrez GE, Isaacs SD, Bazargan N, You X, Thaler LM, Kitabchi AE 2002 Hyperglycemia: an independent marker of in-hospital mortality in patients with undiagnosed diabetes. J Clin Endocrinol Metab 87:978–98
  3. Outcomes of general medical inpatients with diabetes mellitus and new hyperglycaemia. Baker ST Chiang CY Zajac JD et al. MJA 2008;188:340-343.
  4. International Expert Committee report on the role of the A1c assay in the diagnosis of diabetes. Diabetes Care 2009; 32: 1327-1334.