Response: Basal C-peptide Level as a Surrogate Marker of Subclinical Atherosclerosis in Type 2 Diabetic Patients (Diabetes Metab J 2011;35:41-9)

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Diabetes Metab J. 2011;35(2):190-191
Publication date (electronic) : 2011 April 30
doi : https://doi.org/10.4093/dmj.2011.35.2.190
1Department of Internal Medicine, Konyang University Hospital, Konyang University School of Medicine, Daejon, Korea.
2Konyang University Myunggok Medical Research Institute, Daejon, Korea.
3Department of Internal Medicine, Jeju National University Hospital, Jeju National University School of Medicine, Jeju, Korea.
Corresponding author: Dong-Mee Lim. Division of Endocrinology and Metabolism, Department of Internal Medicine, Konyang University School of Medicine, 685 Gasuwon-dong, Seo-gu, Daejeon 302-718, Korea. mdldm@hanmail.net

We appreciate the comments on our study "Basal C-peptide level as a surrogate marker of subclinical atherosclerosis in type 2 diabetes patients," which was published in Diabetes & Metabolism Journal 2011;35:41-49 [1].

Many studies have reported that high levels of HbA1c are strongly associated with increased risks of cardiovascular disease and microvascular complications [2]. However, recent studies have reported that while the use of intensive therapy to target glycated hemoglobin levels below 6% reduces 5-year nonfatal myocardial infarctions, it increases 5-year mortality [3]. Other studies have reported that high density lipoprotein cholesterol, but probably not HbA1c, influences cardiovascular outcomes [4]. It is still unknown, however, whether HbA1c levels are associated with macrovascular complications such as stroke, atherosclerosis, cardiovascular disease, and peripheral arterial disease.

In our study [1], the 10-year risk of coronary heart disease (CHD) was calculated according to the United Kingdom Prospective Diabetes Study (UKPDS) risk engine for each patient based on smoking status, total serum cholesterol, age, serum low density lipoprotein cholesterol, and systolic blood pressure. However, the 10-year CHD risk engine does not take levels of glucose or HbA1c into account. Therefore, in the present study, we show that basal C-peptide is not associated with UKPDS risk engine-related factors and does not independently influence 10-year CHD risk. However, intima media thickness (IMT) can be directly assessed based on arterial vessel wall changes and smooth muscle cell (SMC) proliferation. Insulin resistance and C-peptide are associated with SMC proliferation. Therefore, C-peptide is thought to be an independent factor predicting IMT. In the Atherosclerosis Risk in the Communities (ARIC) study [5], higher levels of endogenous insulin were significantly associated with increased thickness of the carotid artery wall. Reducing the levels of C-peptide and insulin resistance in type 2 diabetic patients, who are especially likely to exhibit many components of metabolic syndrome, may be improved in the outcomes of cases with cardiovascular complications.

References

1. Kim ST, Kim BJ, Lim DM, Song IG, Jung JH, Lee KW, Park KY, Cho YZ, Lee DH, Koh GP. Basal C-peptide level as a surrogate marker of subclinical atherosclerosis in type 2 diabetic patients. Diabetes Metab J 2011;35:41–49. 21537412.
2. Khaw KT, Wareham N, Bingham S, Luben R, Welch A, Day N. Association of hemoglobin A1c with cardiovascular disease and mortality in adults: the European prospective investigation into cancer in Norfolk. Ann Intern Med 2004;141:413–420. 15381514.
3. ACCORD Study Group. Gerstein HC, Miller ME, Genuth S, Ismail-Beigi F, Buse JB, Goff DC Jr, Probstfield JL, Cushman WC, Ginsberg HN, Bigger JT, Grimm RH Jr, Byington RP, Rosenberg YD, Friedewald WT. Long-term effects of intensive glucose lowering on cardiovascular outcomes. N Engl J Med 2011;364:818–828. 21366473.
4. Ferrannini E, Betteridge DJ, Dormandy JA, Charbonnel B, Wilcox RG, Spanheimer R, Erdmann E, Defronzo RA, Laakso M. HDL-cholesterol and not HbA1c was directly related to cardiovascular outcome in PROactive. Diabetes Obes Metab Epub 2011 Apr 1. DOI: 10.1111/j.1463-1326.2011.01404.x.
5. Clark PM, Hales CN. How to measure plasma insulin. Diabetes Metab Rev 1994;10:79–90. 7956678.

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