Kwang-Ik Yang

Higher Glycated Hemoglobin Level Is Associated with Increased Risk for Ischemic Stroke in Non-Diabetic Korean Male Adults

Background The role of glycated hemoglobin (HbA1c) in the prediction of ischemic stroke in non-diabetic subjects is not clear. We performed a study to analyze the role of HbA1c in the risk prediction of ischemic stroke in non-diabetic Korean males adult. Methods A total of 307 non-diabetic male patients with ischemic stroke were enrolled, and 253 age-matched control subjects without a history of diabetes, hypertension, or cardiovascular disease were selected from a Health Check-up database. Anthropometric measurement data, fasting glucose level, lipid profile, and HbA1c level were available for all subjects. Associations of the variables and the presence or absence of ischemic stroke were analyzed. Results The ischemic stroke patient group had significantly higher HbA1c levels (5.8±0.5% vs. 5.5±0.5%, P<0.01) and mean systolic and diastolic blood pressure compared with the control group. Among the variables, smoking, low high density lipoprotein cholesterol, systolic blood pressure, and HbA1c were the significant determinants for ischemic stroke. The highest quartile of HbA1c showed a 9.6-fold increased odds ratio for ischemic stroke compared with the lowest quartile of HbA1c (odds ratio, 9.596; 95% confidence interval, 3.859 to 23.863, P<0.01). The proportion of ischemic stroke patients showed a significant trend for increment as the deciles of HbA1c increased (P for trend <0.01). Conclusion Higher HbA1c indicated a significantly increased risk for ischemic stroke after adjusting for other confounding variables in non-diabetic Korean adult males. HbA1c might have significance in predicting the risk for ischemic stroke even in the non-diabetic range.

Response: Higher Glycated Hemoglobin Level Is Associated with Increased Risk for Ischemic Stroke in Non-Diabetic Korean Male Adults (Diabetes Metab J 2011;35:551-7)

We appreciate the interest and comments on our study, “Higher glycated hemoglobin level is associated with increased risk for ischemic stroke in non-diabetic Korean male adults,” which was published in Diabetes & Metabolism Journal 2011;35:5517. We have responded to the questions below. In our study, we excluded patients with iron-deficiency ane mia, end-stage renal disease, a history of alcohol abuse, persons older than 80 years, pregnant women, children, cancer patients, subjects without fasting blood glucose and HbA1c level data, patients with a history of diabetes or fasting blood glucose level ≥126 mg/dL and patients with cardioembolic ischemic stroke, or recurrent stroke. We analyzed the risk of ischemic stroke only in adult males because our aim was to determine if there were any gender differences considering the fact that HbA1c failed to predict cardiovascular disease in nondiabetic women in a previous report [1]. We also failed to show the usefulness of HbA1c as a predictor of ischemic stroke in non-diabetic Korean women. This re sult might be due to a lack of consideration for hormonal changes or hormonal replacement therapy in postmenopausal women. Recent studies reported that sex hormone and sex hormone-binding globulin, in addition to HbA1c, are associated with a risk of type 2 diabetes [2,3]. Because the women in our study were in their sixties, on average, most female subjects were postmenopausal and likely undergoing drastic hormonal changes, making it difficult to identify HbA1c as a pre dictor of ischemic stroke. Although the smoking rate was significantly different between the control and the stroke patients, our results are reliable because we assessed the risk of ischemic stroke according to the HbA1c levels after adjusting for age, smoking, body mass index, high density lipoprotein cholesterol, low density lipoprotein cholesterol, systolic and diastolic blood pressure, and HbA1c quartile. This was a cross-sectional study such that a definite relationship between HbA1c and ischemic stroke cannot be assumed. Further research in a more ethnically diverse group must be conducted to clarify this relationship. In spite of these limitations, the results of this study are meaningful in that this study was the first to report the association of increasing HbA1c with risk of ischemic stroke in non-diabetic Korean male adults. Our findings warrant future large-scale, long-term prospective cohort studies to evaluate the association between HbA1c and stroke morbidity.