Value of Ambulatory Blood Pressure Monitoring in Type I (Insulin-Dependent) Diabetic Patients With Incipient Diabetic Nephropathy

Ambulatory blood pressure monitoring (ABPM) is currently proposed for measuring blood pressure in type I, insulin-dependent diabetic subjects with incipient diabetic nephropathy. However, the value of this method, in comparison with conventional ones in detecting blood pressure differences between normotensive type I, insulin-dependent diabetic subjects with or without microalbuminuria, is questionable. We obtained systolic, diastolic, and mean blood pressures (SBP/DBP/MBP) in 10 hospitalized normotensive type I, insulin-dependent diabetic subjects with microalbuminuria, and in 29 others without, using a mercury sphygmomanometer (method 1) and an automatic device (Dinamap; method 2) to obtain morning (9 to 11 AM) measurements, and ABPM (SpaceLabs 90207; method 3) to obtain daytime (7 AM to 10 PM) and nighttime (10 PM to 7 AM) measurements. During the daytime, SBP/DBP/MBP values were higher in microalbuminuric than in normoalbuminuric patients, whatever the blood pressure measurement method used (P = .034/.061/.033, two-factor ANOVA). Analysis of 24-h ABPM also showed higher SBP/DBP/MBP in microalbuminuric than in normoalbuminuric patients (P = .022/.040/.016), and demonstrated a defect in nocturnal SBP decrease in microalbuminuric compared with normoalbuminuric patients (P = .028). Stepwise multiple regression analysis indicated nocturnal SBP as the only independent factor determining for microalbuminuria (F = 6.72). Thus ABPM, in relation to other methods, indicates above all that the most relevant blood pressure change in type I insulin-dependent diabetic subjects with microalbuminuria is a defect in nocturnal SBP decrease.