CIRCADIAN BLOOD-PRESSURE VARIATION IN NON-INSULIN-DEPENDENT DIABETES-MELLITUS WITH NEPHROPATHY

We studied a circadian blood pressure variation in relation to the progression of diabetic nephropathy in patients with non-insulin-dependent diabetes mellitus (NIDDM), Age, duration of diabetes, body mass index and glycemic control did not differ among the groups of patients with normo-, micro- and macroalbuminuria. None of the patients received antihypertensive drugs. There were no differences in renal and autonomic functions between normo- and microalbuminuric groups, but these functions were impaired in the macroalbuminuric group. The rise in blood pressure was more apparent in 24-h ambulatory blood pressure (AMBP), especially during night-time, as compared with casual blood pressure. Such blood pressure rise was in accordance with the progression of nephropathy. However, pulse rate did not differ among the three groups. The nocturnal fall in blood pressure was blunted in the micro- and macroalbuminuria groups, but evident in the normoalbuminuric group. In the-latter, daytime systolic blood pressure (SEP) was significantly higher than night-time SEP (123 +/- 5 mmHg vs. 113 +/- 3 mmHg, P = 0.002). In contrast, in the former two groups of patients, there were no significant differences in SEP between daytime and night-time (134 +/- 9 mmHg vs, 134 +/- 9 mmHg, ns, for microalbuminuria and 159 +/- 8 mmHg vs. 165 +/- 7 mmHg, ns, for macroalbuminuria). Urinary albumin excretion was significantly correlated with night-time SEP (r = 0.48, P = 0.015), but not with daytime SEP (r = 0.30, ns). This study indicates that in NIDDM, AMBP monitoring may be useful for the detection of an increase in blood pressure with the progression of diabetic nephropathy and also that the nocturnal decline in blood pressure is blunted even in the microalbuminuric stage, suggesting an association between blood pressure dysregulation and the development of diabetic nephropathy.