Insulin resistance and carotid atherosclerosis in patients with type 2 diabetes

Park, Seok Won; Kim, Soo Kyung; Cho, Yong-Wook; Kim, Dae Jung; Song, Young-Duk; Choi, Young Ju; Huh, Byung Wook; Choi, Sung Hee; Jee, Sun Ha; Cho, Mi Ae; Lee, Eun Jig; Huh, Kap Bum

doi:10.1016/j.atherosclerosis.2008.12.006

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Volume 205, Issue 1 , Pages 309-313, July 2009

Insulin resistance and carotid atherosclerosis in patients with type 2 diabetes☆

Seok Won Park
- Department of Internal Medicine, Pochon CHA University, 351 Yatapdong, Sungnam 463-712, Republic of Korea
- Corresponding author. Tel.: +82 31 780 5211; fax: +82 31 780 5208.
Soo Kyung Kim
- Department of Internal Medicine, Pochon CHA University, 351 Yatapdong, Sungnam 463-712, Republic of Korea
Yong-Wook Cho
- Department of Internal Medicine, Pochon CHA University, 351 Yatapdong, Sungnam 463-712, Republic of Korea
Dae Jung Kim
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Republic of Korea
Young-Duk Song
- Department of Medicine, Ilsan Hospital, Goyang, Republic of Korea
Young Ju Choi
- Huh Diabetes Center and the 21st Century Diabetes and Vascular Research Institute, Seoul, Republic of Korea
Byung Wook Huh
- Huh Diabetes Center and the 21st Century Diabetes and Vascular Research Institute, Seoul, Republic of Korea
Sung Hee Choi
- Department of Internal Medicine, Seoul National University, Seoul, Republic of Korea
Sun Ha Jee
- Department of Epidemiology, Graduate School of Public Health, Yonsei University, Seoul, Republic of Korea
Mi Ae Cho
- Department of Medicine, Yonsei University, Seoul, Republic of Korea
Eun Jig Lee
- Department of Medicine, Yonsei University, Seoul, Republic of Korea
Kap Bum Huh
- Huh Diabetes Center and the 21st Century Diabetes and Vascular Research Institute, Seoul, Republic of Korea

Received 20 May 2008; received in revised form 20 November 2008; accepted 4 December 2008. published online 15 January 2009.

Abstract

Objective

Insulin resistance may provide a crucial link between type 2 diabetes and cardiovascular disease. However, it is still unclear whether insulin resistance itself or hyperinsulinemia is independently associated with subclinical atherosclerosis. We hypothesized that insulin resistance, but not hyperinsulinemia, would be associated with carotid atherosclerosis in patients with type 2 diabetes.

Methods

We examined 2471 patients with type 2 diabetes, consecutively enrolled in Huh Diabetes Center. Insulin sensitivity was directly assessed by a rate constant for plasma glucose disappearance (Kitt) using short insulin tolerance test. Fasting insulin levels were used as a marker of hyperinsulinemia. Both carotid arteries were examined by B-mode ultrasound. Carotid atherosclerosis was defined by having a clearly isolated focal plaque or mean carotid intima-media thickness (IMT) ≥1.1mm.

Results

In multiple regression models, insulin sensitivity index (Kitt) but not hyperinsulinemia was significantly associated with carotid IMT adjusting for known risk factors such as age, sex, BMI, smoking, systolic pressure, HDL and LDL cholesterol. One standard deviation decrease in Kitt was associated with 0.046mm increase in carotid IMT (p=0.015). Furthermore, odds ratio for carotid atherosclerosis was 1.43 (95% CI: 1.10, 1.86) in type 2 diabetic patients with insulin resistance (lowest quartile of insulin sensitivity) adjusting for known risk factors. The results were consistent in all subgroups stratified by sex, age, smoking and hypertension.

Conclusion

Insulin resistance measured by short insulin tolerance test, but not hyperinsulinemia, is independently associated with carotid atherosclerosis in patients with type 2 diabetes.

Keywords: Insulin resistance, Hyperinsulinemia, Carotid atherosclerosis, Type 2 diabetes