Stress hyperglycemia : a prospective study examining the relationship between glucose, cortisol and diabetes in myocardial infarction

Aim: We aimed to explore the relationship between stress, hyperglycemia and diabetes in myocardial infarction (MI), using serum cortisol as a surrogate marker for the severity of stress. Methods: Subjects with acute MI were prospectively recruited upon hospital admission. Serum glucose and cortisol were measured in addition to standard testing. Subjects were defined as having stress hyperglycemia (SH) if they had an admission glucose ≥7.8 mmol/L without a history of glucose intolerance. Subjects were followed up with glucose tolerance testing post-discharge. Results: Of the 200 subjects in the study, 58 had known diabetes/impaired glucose tolerance (IGT), and 45 had SH. There was a positive association between admission glucose and cortisol for the entire cohort (rs = 0.26, p < 0.01). This relationship was present in the subgroup who had SH and then normal glucose post-discharge (rs = 0.53, p = 0.03), but not in SH subjects who had diabetes/IGT on post-discharge testing. It was also evident amongst all subjects with normal glucose (rs = 0.46, p < 0.01), but not those with diabetes/IGT in general. On multivariate analysis, admission glucose was a positive predictor and cortisol a negative predictor of abnormal glucose tolerance. Conclusions: Our data suggests that SH with MI reflects either underlying glucose intolerance or more severe stress in people without glucose intolerance.