Circadian blood pressure variation in patients with type 2 diabetes--relationship to macro- and microvascular subclinical organ damage.

Abstract

To explore the association between nocturnal blood pressure (BP) dipper status and macro- and microvascular organ damage in type 2 diabetes. Cross-sectional data from 663 patients with type 2 diabetes, aged 55-66 years, were analysed. Nurses measured office BP and ambulatory BP during 24h. Individuals with ≥ 10% difference in nocturnal systolic blood pressure (SBP) relative to daytime values were defined as dippers. Non-dippers were defined as <10% nocturnal decrease in SBP. Estimated glomerular filtration rate (GFR) was calculated and microalbuminuria was measured by albumin:creatinine ratio (ACR). Aortic pulse wave velocity (PWV) was measured with applanation tonometry over the carotid and femoral arteries. We identified 433 dippers and 230 subjects with a nocturnal non-dipping pattern. Nocturnal SBP dipping was independently of office SBP associated with decreased PWV (p = 0.008), lower ACR (p = 0.001) and NT-proBNP (p = 0.001) and increased GFR (p<0.001). We conclude that diurnal BP variation provides further information about early macro- and microvascular subclinical organ damage that goes beyond standardized office BP measurements in patients with type 2 diabetes.