Oral glucose tolerance test is needed for appropriate classification of glucose regulation in patients with coronary artery disease: a report from the Euro Heart Survey on Diabetes and the Heart
- M Bartnik1,
- L Rydén1,
- K Malmberg1,
- J Öhrvik1,
- K Pyörälä2,
- E Standl3,
- R Ferrari4,
- M Simoons5,
- J Soler-Soler6,
- on behalf of the Euro Heart Survey Investigators
- 1Cardiology Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
- 2Department of Medicine, Kuopio University Hospital, Kuopio, Finland
- 3Department of Medicine (Endocrinology), Teaching Hospital, Munich-Schwabing, Germany
- 4University of Ferrara and Fondazione S Maugeri, Ferrara, Italy
- 5Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands
- 6Service of Cardiology, University Hospital Vall d’Hebron, Barcelona, Spain
- Correspondence to:
Dr L Rydén
Department of Cardiology, Karolinska University Hospital, Solna, 171 76 Stockholm, Sweden;
- Accepted 25 July 2006
- Published Online First 11 August 2006
Background: Patients with coronary artery disease (CAD) and abnormal glucose regulation (AGR) are at high risk for subsequent cardiovascular events, underlining the importance of accurate glucometabolic assessment in clinical practice.
Objective: To investigate different methods to identify glucose disturbances among patients with acute and stable coronary heart disease.
Methods: Consecutive patients referred to cardiologists were prospectively enrolled at 110 centres in 25 countries (n = 4961). Fasting plasma glucose (FPG) and glycaemia 2 h after a 75-g glucose load were requested in patients without known glucose abnormalities (n = 3362). Glucose metabolism was classified according to the World Health Organization and American Diabetes Association (ADA; 1997, 2004) criteria as normal, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or diabetes.
Results: Data on FPG and 2-h post-load glycaemia were available for 1867 patients, of whom 870 (47%) had normal glucose regulation, 87 (5%) had IFG, 591 (32%) had IGT and 319 (17%) had diabetes. If classification had been based on the ADA criterion from 1997, the proportion of misclassified (underdiagnosed) patients would have been 39%. The ADA 2004 criterion would have overdiagnosed 8% and underdiagnosed 33% of the patients, resulting in a total misclassification rate of 41%. For ethical concerns and practical reasons, oral glucose tolerance test (OGTT) was not conducted in 1495 of eligible patients. These patients were more often women, had higher age and waist circumference, and were therefore more likely to have AGR than those who were included. A model based on easily available clinical and laboratory variables, including FPG, high-density lipoprotein cholesterol, age and the logarithm of glycated haemoglobin A1c, misclassified 44% of the patients, of whom 18% were overdiagnosed and 26% were underdiagnosed.
Conclusion: An OGTT is still the most appropriate method for the clinical assessment of glucometabolic status in patients with coronary heart disease.
- ADA, American Diabetes Association
- AGR, abnormal glucose regulation
- CAD, coronary artery disease
- FPG, fasting plasma glucose
- HbA1c, glycated haemoglobin A1c
- HDL-C, high-density lipoprotein cholesterol
- IFG, impaired fasting glucose
- IGT, impaired glucose tolerance
- IGR, impaired glucose regulation
- NGR, normal glucose regulation
- OGTT, oral glucose tolerance test
- WHO, World Health Organization
Published Online First 11 August 2006
Funding: This study was supported by grants from the European Society of Cardiology, the Swedish Heart and Lung Foundation, AFA Insurance and King Gustav V and Queen Victoria’s Foundation.
Competing interests: None declared.
Contributors: The Euro Heart Survey on Diabetes and the Heart was undertaken under the auspices of the European Society of Cardiology under the initiative of LR who chaired the expert committee on designing and preparation of this survey. Patients were recruited in the respective centres under the supervision of the investigators, whose work was coordinated by national coordinators (as detailed elsewhere).4 Under the supervision of LR and KM, MB prepared proposals of the study protocol and case record forms that were reviewed and approved by all expert committee members. Statistical modelling was conceived and performed by JÖ. Data were analysed by MB and JÖ, who, together with KP, ES, LR and KM, discussed their interpretation. MB, LR and JÖ wrote this report, which was revised by the authors.