Ambulatory blood pressure monitorization is a valuable tool for the assessment of diurnal variation of blood pressure and diagnosis of hypertension. Altered diurnal blood pressure variation is observed in diabetic patients with overt nephropathy. In this study, we planned to investigate the relationship between diabetic microvascular complications, mainly autonomic neuropathy and early stage nephropathy, and diurnal blood pressure variation in type 2 diabetic patients. We performed 24 hour ambulatory blood pressure monitoring, 24 hour urinary albumin excretion measurements, and autonomic neuropathy tests in healthy controls (C) (n=13), normoalbuminuric (N) (n=30) and microalbuminuric (M) (n=18) type 2 diabetic patients. Frequency of autonomic neuropathy was significantly higher in group M (45%) compared with group C (p<0.005). Although there was no significant difference between day and night blood pressures and heart rates between groups, the amount of dipping of sistolic, diastolic and mean arterial pressures in group M (5.5±3, 9.6±5, 7.1±4%) was decreased compared with group C (10±2, 14.9±3, 12.3±2%) (p<0.005) and group N (8.3±4, 11.9±5, 10.1±4 %) (p<0.05). Frequency of non-dippers was increased in groups M (83%; p<0.0005) and N (57%; p<0.01) compared with group C (18%). The frequency of non-dippers was found to be higher in patients with autonomic neuropathy (85% vs. 45.5%, p<0.05) and the frequency of autonomic neuropathy was found to be significantly higher in non-dipper patients (44.5% vs. 10%, p<0.05). In conclusion increased frequency of nondippers in patients with microalbuminuria and/or autonomic neuropathy demonstrates the relation between altered diurnal blood pressure rhythm and microvascular complications.
Keywords: Type 2 diabetes mellitus, autonomic neuropathy, microalbuminuria