Factors determining the 24-h blood pressure profile in normotensive patients with type 1 and type 2 diabetes

Open Access
Publisher Website
Google Scholar
Abstract
Some controversy still exists about factors involved in the abnormal circadian pattern of blood pressure (BP) in diabetes, while prognostic value of non-dipping condition is being increasingly recognised. This study was aimed at evaluating the relative influence of autonomic neuropathy (AN) and albumin excretion on 24-h BP profile in type 1 and type 2 diabetes. We measured AN cardiovascular tests, 24-h ambulatory BP, and urinary albumin excretion rate (UAE) in 47 type 1 and 34 type 2 normotensive non-proteinuric diabetic patients. In type 1 diabetic patients day–night differences (Δ) in systolic and diastolic BP were lower in those with AN than in those without (3 ± 9 vs 10 ± 6%, P < 0.01, and 8 ± 9 vs 16 ± 6%, P < 0.001), and in univariate regression analysis they were inversely related to both autonomic score, index of degree of AN (r = −0.61, P < 0.001 and r = −0.65, P < 0.001), and to 24-h UAE (r = −0.39, P < 0.01 and r = −0.46, P < 0.001). In type 1 diabetic patients AN was also associated with lower nocturnal decrease in UAE (patients with AN vs without AN: −37 ± 214 vs 49 ± 37%, P < 0.05), and with a stronger relationship between simultaneous 24-h UAE and 24-h BP (for systolic BP patients with AN vs without AN: r = 0.62, P < 0.01 vs r = 0.28, NS). In type 2 diabetic patients Δ systolic BP was reduced in patients with AN compared to those without (4 ± 7 vs10 ± 4%, P < 0.01), and it was related only to autonomic score (r = −0.42, P < 0.01). Using a stepwise regression analysis, in type 1 diabetic patients autonomic score was the variable of primary importance for Δ BP, while in type 2 diabetic patients it was the unique determinant not only of Δ systolic BP but also of 24-h systolic BP. In conclusion, AN is the pivotal factor of blunted nocturnal fall in BP in both type 1 and type 2 diabetic patients. In type 1 diabetic patients AN is associated with attenuated circadian pattern of albuminuria and with a steeper relationship between albuminuria and BP, in type 2 diabetic patients AN is the only factor related to elevated 24-h BP levels. Longitudinal studies are needed to establish the potential role of autonomic dysfunction as a progression promoter for nephropathy and hypertension in type 1 and type 2 diabetes respectively.

This publication has 0 references indexed in Scilit: