Reduced diurnal variation of blood pressure in non-insulin-dependent diabetic patients with microalbuminuria.

In essential hypertension reduced diurnal blood pressure (BP) variation is associated with an increased prevalence of target organ damage. We have examined diurnal BP variation in 25 microalbuminuric (MA) and 19 normoalbuminuric (NMA) patients with non-insulin-dependent diabetes and related albumin excretion rate (AER) to diurnal BP variation in the microalbuminuric group. There were no significant differences in age, body mass index (BMI), renal function, diabetic control, clinic or daytime ambulatory BP between the groups. Night-time SBP was higher (MA 145 mm Hg (137-153), NMA 132 mm Hg (125-139); P = 0.019) in the microalbuminuric group while the diurnal variation as assessed by the day-night dip in BP was significantly reduced in the microalbuminuric group (systolic: (mean (95% confidence intervals) MA 4.7% (1.7-7.7), NMA 12.8% (9.5-16.0), p = 0.001; diastolic: MA 6.5% (3.0-10.0), NMA 14.5% (10.2-18.8), P = 0.007). Within the microalbuminuric group, the systolic dip in BP was inversely related to the AER (r = -0.48, P = 0.015). Reduced diurnal BP variation and high night-time BP may contribute to target organ damage in diabetes.