Abnormal Circadian Rhythm of Blood Pressure in Relation to Diabetic Complications in Patients with Non-Insulin Dependent Diabetes Mellitus

Abstract

We measured blood pressure (BP) for 24hr in 61 patients with non-insulin dependent diabetes mellitus (NIDDM) and 10 healthy control subjects by the use of a non-invasive ambulatory BP monitoring system (TM-2420).
In the control subjects, mean (±SD) levels of systolic BP during the daytime (0900-2300) were higher than in the nocturnal period (2300-0700)(114±12 vs 100±9mm Hg, p<0.05). In 46 out of 61 diabetic patients (group A), the circadian rhythm of systolic BP was similar to that of controls (day 120±61 vs night 108±15mm Hg, p<0.05). On the other hand, in 15 patients, mean systolic+BP levels at night were much higher than those during the daytime (group B)(135±16 vs 27±12mm Hg, p<0.05). Group B had a higher incidence of hypertension and diabetic nephropathy that did group A. Serum creatinine levels and CCr were significantly greater in group B than in group A. In contrast, CV% of R R intervals on ECG at rest and after deep breathing were significantly lower in group B than in group A.
In the diabetic groups, the difference in mean systolic BP levels during the daytime, as compared to at night. was significantly related to both CV% and CCr.
These findings indicate that impaired circadian rhythm of BP is closely related to altered parasympathetic nervous system function and diabetic nephropathy in NIDDM.