Detection of glucose metabolism disorders in coronary patients enrolled in cardiac rehabilitation: Is glycated haemoglobin useful? Data from the prospective REHABDIAB study

Abstract

Introduction Diabetes and pre-diabetes are highly prevalent in patients with a history of acute coronary syndrome. This is why screening for glucose metabolism disorders is recommended in patients following an acute coronary syndrome. The aim of our study was to determine whether glycated haemoglobin alone compared with the oral glucose tolerance test could allow effective screening for glucose metabolism disorders in acute coronary syndrome patients undergoing cardiac rehabilitation. Patients and methods Among 347 patients with a recent history of acute coronary syndrome enrolled in our cardiac rehabilitation centre, 267 patients without previously known diabetes were recruited for this prospective study with performance of both oral glucose tolerance test and glycated haemoglobin measurement. The patients were divided into three groups: newly diagnosed diabetes mellitus, pre-diabetes and normoglycaemia according to the oral glucose tolerance test and glycated haemoglobin results. The results obtained with glycated haemoglobin were compared with those obtained with the oral glucose tolerance test, considered as the reference. Results For the diagnosis of diabetes, glycated haemoglobin had a sensitivity of 72% and a specificity of 100%. Positive and negative predictive values were high at 100% and 96%, respectively. However, for the diagnosis of pre-diabetes the sensitivity of glycated haemoglobin was low at 64% as were the specificity (53%) and the positive predictive values (37%). Glycated haemoglobin overdiagnosed pre-diabetes (52% vs 30%, p< 0.0001). For the diagnosis of normoglycaemia, the sensitivity of glycated haemoglobin was also low (48%). Conclusion According to our study, glycated haemoglobin has low sensitivity and specificity for the detection of pre-diabetes in patients with coronary disease enrolled in cardiac rehabilitation, and glycated haemoglobin over-diagnoses pre-diabetes in comparison with the oral glucose tolerance test.

Risk and management of pre-diabetes

“…However, it has been debated how valuable this is in clinical practice. 6,7 HbA1c does not diagnose all people with T2DM, and the only way to identify impaired glucose tolerance (IGT) is via an OGTT. 8 Combinations of different measurements define several forms of pre-diabetes.…”

Is HbA1c a good diagnostic test for (pre)diabetes in cardiac rehabilitation patients?

“…Elsewhere in this issue, Tutalashvili and colleagues report a study designed to determine whether HbA1c cut-off levels defined by the ADA could allow effective diagnosis of (pre-)diabetes according to OGTT criteria defined by the World Health Organization (WHO), in a cohort entering cardiac rehabilitation after an acute coronary syndrome (ACS). 5 In their study, HbA1c had a sensitivity of 72% and a specificity of 100% for diabetes, and a low sensitivity (64%) and specificity (53%) for pre-diabetes. Also, HbA1c ‘overdiagnosed’ pre-diabetes (52% vs. 30%).…”

The global epidemics of diabetes in the 21st century: Current situation and perspectives

“…Thus, HbA1c only contributed a small proportion above that disclosed by FPG plus 2hPG. 26 These and other data, 26,27 although not undisputed, 28 favour the use of OGTT, if the ambition is to disclose as many dysglycaemic patients as possible in high-risk populations with established CAD for appropriate risk stratification and treatment with glucose-lowering agents that also reduce mortality and cardiovascular disease (Figure 2). 29 This approach contrasts with the regular diagnostic algorithm in the general population, which involves using risk score questionnaires for screening and the use of HbA1c measurements for diagnosis.…”