NONDIPPING OF NOCTURNAL BLOOD-PRESSURE IS RELATED TO URINARY ALBUMIN EXCRETION RATE IN PATIENTS WITH TYPE-2 DIABETES-MELLITUS

Although cardiovascular and cerebrovascular morbidity and mortality in type 2 diabetic patients is closely related to urinary albumin excret ion rate (UAER), the causative mechanisms are not yet identified. The aim of our study was to define the circadian variation of blood pressu re (BP) in 72 type 2 diabetic patients (mean age 60 years, mean diabet es mellitus duration: 12 years) in comparison with 41 nondiabetic cont rols with essential hypertension (mean age 58 years) by using ambulato ry blood pressure measurement. Thirty diabetic patients had normal UAE R (< 30 mg/24 h), 27 had microalbuminuria (30 to 300 mg/24 h), and 15 had persistent proteinuria (> 300 mg/24 h). Systolic blood pressure du ring both nighttime and daytime was significantly elevated in type 2 d iabetic patients with macroalbuminuria compared to controls and patien ts with normal UAER. During nighttime even type 2 diabetic patients wi th microalbuminuria had significantly elevated systolic blood pressure compared to controls with essential hypertension. We also observed a correlation of nocturnal blood pressure to UAER (systolic: r = 0.32, P < .007 and diastolic: r = 0.24, P < .04). Nondipping (defined as a re duction of nocturnal BP < 10%) was observed in 80% of the macroalbumin uric, 74% of the microalbuminuric, but only in 43% of the normoalbumin uric type 2 diabetic patients and in 37% of the controls (P < .04). Si nce a loss of circadian variation of BP is closely related to vascular complications in nondiabetics, our findings may indicate an important relationship between nondipping of BP and the high morbidity and mort ality rate in diabetic patients with increased UAER.