Importance of Investigating Mild Hyperglycaemia Using Oral Glucose Tolerance Test in the Setting of Acute Coronary Syndrome: Prospective Investigational Study

Abstract

The aim of this article is to estimate the prevalence of true dysglycaemic syndromes (DS) (includes presence of diabetes mellitus [DM], impaired fasting glucose [IFG] and impaired glucose tolerance [IGT]) in patients with acute coronary syndromes (ACS) and mild fasting hyperglycaemia from an area in New Zealand with the country's highest prevalence of dysglycaemia. Cardiac risk factor data and laboratory findings for 565 consecutive ACS patients were obtained from the hospital database between January 2007 and August 2008. On admission, 175 patients had DS and 168 were normoglycaemic (FBG <5.6 mmol/L). The remaining 222 patients (with previously unknown glycaemic status) had mild fasting hyperglycaemia .9 mmol/L) on admission. This group with mild fasting hyperglycaemia were offered oral glucose tolerance testing (OGTT) >3 months post-discharge to eliminate cases of stress hyperglycaemia. 121 patients underwent OGTT and 41 patients (a third) were found to have true DS (DM in 13, IGT or IFG in 28). Patients who did not undergo OGTT due to a variety of reasons (n=101) had significantly higher body mass index, waist circumference, and higher concentrations of triglycerides and low-density lipoprotein cholesterol, and therefore might be at a higher risk for true DS than those tested. The conclusion is that a third of the OGTT cohort had true DS and therefore even mild hyperglycaemia in this setting should be carefully investigated.