This study was designed to examine the circadian pattern of blood pressure (BP) during ambulatory blood pressure monitoring (ABPM) in normotensive patients with type 1 diabetes and its association with microalbuminuria. Methods - 37 patients with type 1 diabetes without hypertension, aged 26.5 ± 6.7 years and with 8 years (1-34) of disease, were submitted to determination of the albumin excretion rate (AER) and ABPM. Microalbuminuria was defined when two out of three nocturnal urine samples had AER between 20-200µg/min. Non-dippers were defined as subjects with nocturnal fall in either systolic or diastolic BP of less than 10%. 9 patients were defined as microalbuminuric. 8/9 patients microalbuminuric (89%) and 22/28 normoalbuminuric (78%) were non-dippers systolic (p= 0.656) and 5/9 (55%) vs. 5/28 (18%) respectively, were non-dippers diastolic (p= 0.041). The impaired fall in diastolic BP was associated with higher AER [20.6 (2.2-82.4) vs. 6.2 (2.1-63.7µg/min); p= 0.04], duration of diabetes [10.5 (2-18) vs. 7 (1-34 years); p= 0.043] and was also associated with impaired fall in systolic BP. A logistic regression model was used and impaired fall in diastolic BP correlated significantly as so as with microalbuminuria (p= 0.036; R= 0,236). The impaired fall of systolic BP in normotensive type 1 diabetic patients was the most frequent and the phenomenon non-dipper for diastolic BP was associated mainly with microalbuminuria.
Ambulatory blood pressure monitoring; Autonomic neuropathy; Diabetic nephropathy; Type 1 diabetes
