Background: While glucose levels on admission are clearly a much stronger predictor of short term adverse outcomes than diabetes status, there is a paucity of data on how diabetes status impacts the hyperglycemia-induced increased risk.
Methods: 2786 patients admitted to the hospital with acute coronary syndrome (ACS) and diabetic level hyperglycemia (random >11.1 mmol/L or fasting >7 mmol/L) were identified from a Gulf registry of ACS. We divided the cohort into two groups. Those who were previously known to have diabetes mellitus were identified as the known diabetes group, and the non-diabetic group included those without a previous diabetes diagnosis. We used logistic regression models to assess the effect of glycemic status on hospital mortality and other patient outcomes including heart failure, stroke, recurrent ischemia, cardiogenic shock, major bleeding, and ventilation.
Results: About two-thirds of the hyperglycemics on admission had been diagnosed previously with diabetes. After adjusting for age, in-hospital mortality was significantly higher in the non-diabetic group (OR: 2.36; 95% CI 1.54-3.61) compared to the diabetic group. As for the other outcomes, known diabetes patients had significantly lower incidences of heart failure, cardiogenic shock, and ventilation compared to non-diabetic patients.
Conclusion: The effects of hyperglycemia are mitigated by the presence of the chronic diabetic state, and thus, hyperglycemia has a worse effect in those not known to have chronic diabetes. These findings are important and call for further investigation.