Glucose homeostasis abnormalities assessed by an OGTT in coronary artery disease patients during admission and follow-up at ambulation

Background: Most non diabetic patients admitted with acute coronary syndrome (ACS) demonstrate an abnormality in glucose homeostasis. It was claimed that an oral glucose tolerance test (OGTT) undertaken during the admission is a good indicator of the patient's glycemic status. Aim: The aim of this study was to examine the reproducibility of OGTT based dysglycemic diagnosis during the acute admission and during an ambulatory visit in patients with ischemic heart disease (IHD). Methods: We have repeated an OGTT on 29 patients with IHD who had been tested with OGTT during hospitalization for ACS. Results: In 20 of the 29 (69%) patients the OGTT results improved on the repeated ambulatory test. This improvement was evident in the post-prandial glucose level yet not in the fasting levels. There were no significant differences in beta-cell function or in insulin sensitivity between the OGTTs as assessed by HOMA calculations. However there was tendency for improvement in insulin sensitivity at 2h when assessed by the SI120 formula. Conclusions: In this pilot study we found that impaired post-prandial glucose control in patients with ACS improves when retested at ambulation. Therefore, it is probably better to perform the OGTT as an ambulatory test and not during the acute admission for defining abnormalities in glucose homeostasis of patients with ACS.