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21-07-2011 | Diabetes | Article

Impaired glycemic, BP variability linked to CV damage markers in diabetes

Abstract

Free abstract

MedWire News: Impaired glycemic variability (GV) and blood pressure (BP) variability are associated with markers of endothelial dysfunction and cardiovascular damage in well controlled, uncomplicated Type 2 diabetic patients, research shows.

The pathophysiologic mechanism responsible could relate to activation of the oxidative stress pathway, they say.

As reported in the journal Diabetes Care, Alessandra Di Flaviani (University of Rome Tor Vergata, Italy) and colleagues evaluated the effect of GV, variability in systolic (S)BP and diastolic (D)BP, and oxidative stress on endothelial function and cardiac mass in 26 uncomplicated diabetic patients receiving diet and/or metformin treatment.

The percentage change in SBP from day to night was used to divide all subjects into the two groups dipper (D, 17.5%) and nondipper (ND, 5.9%), with a change of less than 10% indicating a nondipper profile.

After the patients had undergone an overnight fast, the researchers performed 24-hour continuous glucose monitoring as well as BP and electrocardiogram monitoring. They also assessed urinary creatinine and 8-iso-PGF2α levels and measured carotid intima-media thickness (IMT), left ventricular mass index (LVMI), and endothelial function.

The authors found that IMT and LVMI were increased in ND versus D (0.77 mm vs 0.68 mm and 67 vs 55, respectively).

They also found that continuous overall net glycemic action (CONGA-2) was positively associated with LVMI and day-to-night change in SBP, and negatively associated with LVMI, while urinary 8-iso-PGF2α was positively associated with LVMI. However, no association was observed between HbA1c or MBG and LVMI.

They say their study demonstrates that GV evaluated as CONGA-2, rather than overall glycemic load, has a deleterious effect on LVMI in well controlled Type 2 diabetic patients.

"As CONGA-2 detects small glycemic swings, occurring over short intervals, our data suggest that such rapid and small glycemic excursions seem to be involved in the development of early cardiovascular damage in Type 2 diabetic patients with short-term disease and optimal glycemic control," they explain.

Further analysis also revealed a positive correlation between 8-iso-PGF2α and CONGA-2 as well as a negative correlation with day-to-night change in SBP and DBP, suggesting that an increased activation of oxidative stress might represent the common pathogenetic mechanism linking GV and abnormal circadian BP rhythm with an increased LVMI, they say.

"Intervention studies are needed to investigate the benefits of the correction of glucose fluctuations on cardiovascular parameters, and to address the issue of treatment choices, in diabetic patients," they conclude.

MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Sally Robertson