A Possible Relationship of Nocturnal Blood Pressure Variability with Coronary Artery Disease in Diabetic Nephropathy

• Published in: Clinical and experimental hypertension (1993) 2007, Vol.29 (1), p.31-42
• Main Authors: Tamura, Kouichi, Tsurumi, Yuko, Sakai, Masashi, Tanaka, Yutaka, Okano, Yasuko, Yamauchi, Junji, Ishigami, Tomoaki, Kihara, Minoru, Hirawa, Nobuhito, Toya, Yoshiyuki, Yabana, Machiko, Tokita, Yasuo, Ohnishi, Toshimasa, Umemura, Satoshi
• Format: Article
• Language: English
• Subjects: Aged; Blood Pressure - physiology; body mass index; cholesterol; Circadian Rhythm - physiology; coronary artery disease; Coronary Disease - etiology; Coronary Disease - physiopathology; diabetic nephropathy; Diabetic Neuropathies - complications; Diabetic Neuropathies - physiopathology; Female; Humans; Hypertension - complications; Hypertension - physiopathology; Male; Middle Aged; norepinephrine; Regression Analysis; Risk Factors; short-term blood pressure variability; Sympathetic Nervous System - physiology
• ISSN: 1064-1963; 1525-6006
• DOI: 10.1080/10641960601096760

Evidence suggests a relationship between short-term blood pressure (BP) variability and cardiovascular target-organ damage. Although a blunted nocturnal decrease in BP and reduced heart rate variability have been shown to be associated with cardiovascular morbidity in diabetic patients, little information is available on short-term BP variability. In this study, short-term BP variability was assessed in 36 subjects with type 2 diabetes and overt nephropathy who underwent ambulatory BP monitoring, and the factors that correlated with short-term BP variability were examined. The incidence of coronary artery disease (CAD) was significantly greater in the patients with increased 24-h systolic BP variability (67% versus 11%; p < 0.0005), while that of cerebrovascular disease was not significantly affected (61% versus 50%). Multiple stepwise regression analysis revealed that serum cholesterol (cholesterol) and plasma norepinephrine (p-NE) were significant and independent contributors to nighttime systolic BP variability (partial R2 = 0.490, p < 0.001; partial R2 = 0.470, p < 0.001) and demonstrated that body mass index and p-NE were primary determinants of nighttime diastolic BP variability (partial R2 = 0.539, p < 0.0005; partial R2 = 0.304, p < 0.05). Diabetic nephropathy patients with CAD had significantly increased daytime systolic (17.8 mmHg versus 13.1 mmHg, p < 0.0005), nighttime systolic (17.4 mmHg versus 10.5 mmHg, p < 0.0001), and nighttime diastolic (10.4 mmHg versus 7.2 mmHg, p < 0.05) BP variability. Furthermore, logistic regression analysis demonstrated that nighttime systolic BP variability was an independent risk factor for CAD (odds ratio 3.13 [95% CI 1.02-9.61]; p < 0.05). The increase in nighttime BP variability is associated with a proportional sympathetic activation in diabetic nephropathy. Elevated short-term BP variability combined with relative sympathetic prevalence during the night might represent an important risk factor for cardiovascular events in the diabetic population.