Objective: To determine the impact of elevated in-hospital glucose level on outcome of patients with acute myocardial infarction (AMI), and evaluate the role of diabetes mellitus as a risk factor of AMI.
Methods: The study included a retrospective analysis of AMI patients who were admitted to No. 81 Hospital of PLA from January 2000 to May 2010. In patients without a history of diabetes, and those with fasting blood glucose (FBG)≥7.0 mmol/L at admission but returned to normal range soon after admission were defined as stress hyperglycemia of non-diabetic AMI patients. Both diabetic patients and non-diabetic patients were stratified into four mutually exclusive groups according to FBG levels: <7.0, 7.0-7.9, 8.0-11.0 and ≥11.1 mmol/L. The in-hospital mortality, incidence of complications, and treatment to lower glucose level were analyzed. Logistic regression analysis was conducted on risk factors of outcome of AMI patients.
Results: One hundred and fifty-two AMI patients were enrolled with 45 diabetic patients and 107 patients without previous diabetes. In diabetic group patients with FBG≥8.0 mmol/L and those with FBG≥11.1 mmol/L accounted for 73.3% (33 cases) and 46.7% (21 cases), respectively. In non-diabetic group patients with stress hyperglycemia accounted for 43.9% (47 cases), among which patients with FBG levels of 7.011.0 mmol/L accounted for 91.5% (43 cases). Compared with the non-diabetic group, the in-hospital mortality was significantly higher in diabetic group (35.6% vs. 15.9%, P=0.007). In both groups, the in-hospital mortality presented an elevating tendency with an increasing FBG level. Multivariate Logistic regression analysis demonstrated that in diabetic group patients with FBG≥8.0 mmol/L had 12.28-fold higher risk of death than patients with FBG<8.0 mmol/L, and that in non-diabetic group patients with FBG≥7.0 mmol/L had 4.81-fold higher risk of death than patients with FBG<7.0 mmol/L. FBG was an independent risk factor of death with relative odds ratio (OR) 1.03, with 95% confidence interval (95%CI) 1.01-1.16, P=0.012, and OR 1.56, 95%CI 1.09-2.23, P=0.015 in diabetic group and non-diabetic group, respectively. The incidence of congestive heart failure in diabetic group was significantly higher than that in non-diabetic group (40.0% vs. 22.4%, P=0.027). In non-diabetic group, the incidence of lung infection, congestive heart failure, serious arrhythmias and acute cerebrovascular events (51.1%, 34.0%, 27.7%, 14.9%, respectively) was increased significantly in patients with FBG≥7.0 mmol/L than that in patients with FBG<7.0 mmol/L (18.3%, 13.3%, 10.0%, 0, respectively, P<0.05 or P<0.01). This association was not seen in diabetic group. 80.0% of patients (36 cases) in diabetic group received anti-hyperglycemia treatments in which insulin therapy accounted for 63.9% (23 cases), while there was not even 1 patient who needed insulin therapy in non-diabetic patients with stress hyperglycemia.
Conclusion: In-hospital mortality and complications were significantly increased in diabetic AMI patients and in non-diabetic AMI patients with stress hyperglycemia. Both a history of diabetes mellitus and stress hyperglycemia have strong influence on AMI prognosis. It seems to be more plausible to collaborate blood glucose level with history of diabetes in considering risk factors in AMI patients.