Zigzagged Augmentation Index in Diabetes

Abstract

Although the patients with diabetic nephropathy suffered high cardiovascular risk, augmentation index (AI) in diabetic nephropathy has been poorly characterized. Cross-sectional studies were performed on 26 diabetic and 27 nondiabetic nephropathic patients. Home blood pressure was examined. In addition, blood pressure, pulse rate, and AI were measured in both supine and sitting positions. Patient backgrounds such as age, sex, sitting blood pressure, and pulse rate were similar between two groups. Circadian variations of home blood pressure were preserved in nondiabetic patients, but disappeared in diabetes. Changing from supine to sitting position induced greater decrements of systolic blood pressure (ΔSBP −9 ± 8 mmHg) and AI (ΔAI −7 ± 10) in the diabetic group than in nondiabetic patients (ΔSBP −4 ± 12 mmHg, ΔAI −2 ± 9). Multivariate regression analysis revealed that AI in a sitting position correlated positively to SBP and inversely to pulse rate. Of interest, AI in supine position related positively to age, the presence of diabetes and SBP, and inversely to pulse rate. The present data indicate autonomic dysfunction in patients with diabetic nephropathy. Furthermore, our findings provide the evidence that autonomic dysfunction elicits an inadequate physiological arterial contraction in response to postural change, thereby reducing AI that results in the fall of SBP. Finally, the present results suggest that AI in supine, but not sitting position, is suited for detecting cardiovascular risk in diabetes.

Keywords:

• autonomic nerve
• central blood pressure
• physiological arterial contraction
• home blood pressure
• circadian rhythm

Acknowledgments

The authors thank Ms. Sachiko Nakazato for secretarial assistance during the study and in the preparation of the manuscript.

Declaration of Interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.