Cardiovascular Autonomic Dysfunction Predicts Severe Hypoglycemia in Patients with Type 2 Diabetes Mellitus: A Ten-year Follow-up Study
- Jae-Seung Yun, MD1,
- Ji-Hyun Kim, MD, PHD1,
- Ki-Ho Song, MD, PHD1,
- Yu-Bae Ahn, MD, PHD1,
- Kun-Ho Yoon, MD, PHD1,
- Ki-Dong Yoo, MD, PHD2,
- Yong-Moon Park, MD, PHD3,4 and
- Seung-Hyun Ko, MD, PHD1⇑
- 1Division of Endocrinology and Metabolism,
- 2Division of Cardiology,
- 3Department of Internal Medicine, Department of Preventive Medicine,
- 4The Catholic University of Korea, Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
- Corresponding Author: Seung-Hyun Ko, E-mail:
Objective The aim of this study was to investigate the development of severe hypoglycemia (SH) in the presence of cardiovascular autonomic neuropathy (CAN) in patients with type 2 diabetes.
Research design and methods From January 2001 to December 2002, a total of 894 patients with type 2 diabetes were enrolled. A cardiovascular autonomic function test (AFT) was performed using heart rate variability parameters: expiration-to-inspiration ratio, response to Valsalva maneuver and standing. From the results of the each three test (0 for normal, 1 for abnormal), a total AFT score of 1 was defined as early CAN, and a AFT score of ≥ 2 was defined as definite CAN.
Results The median follow-up time was 9.5 years. The mean age was 54.5 ± 10.1 years and the duration of diabetes was 8.9 ± 6.3 years. One hundred and ninety-six (31.4%) patients showed an abnormal cardiovascular AFT score at baseline. Sixty-two (9.9%) patients experienced 77 episodes of SH (1.33 per 100 patient-years). The events of SH increased as the CAN score increased (23 (5.4%) patients with normal, 17 (17.2%) patients with early, and 22 (22.7%) patients with definite CAN; P for trends < 0.001). Cox proportional hazard regression analysis revealed that SH was associated with definite CAN (normal vs. definite CAN, HR 2.43, 95% CI 1.21 – 4.84; P = 0.012).
Conclusions Definite CAN was an independent prognostic factor for the development of SH in patients with type 2 diabetes.
- Received May 15, 2013.
- Accepted August 12, 2013.
- © 2013 by the American Diabetes Association.
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