Ambulatory blood pressure in microalbuminuric type 1 diabetic patients.

Twenty-four-hour ambulatory blood pressure (AMBP) was performed in microalbuminuric (micro.) type 1 diabetic patients, with the aim of comparison with a matched group of normoalbuminuric patients (normo.) and healthy controls. Thirty-four patients without antihypertensive medication were investigated in each group. Urinary albumin excretion (UAE) for micro. was (geometric mean, tolerance factor microgram/min) 51.7 x/divided by 1.94, 5.1 x/divided by 1.88 for normo. and 5.2 x/divided by 1.75 for controls. Twenty-four-hour AMBP (mean systolic/diastolic mm Hg +/- SD) was significantly higher in micro. (131 +/- 10/78 +/- 7) than in normo. (122 +/- 8/73 +/- 6; P less than 0.001/P less than 0.01). No 24-hour AMBP difference between normo. and controls (120 +/- 9/71 +/- 7) was found. No difference in the night/day ratio of blood pressure was found between the diabetic groups. Coefficient of variation for day time systolic measurements did not show any intergroup difference. Systolic day time blood pressure for the pooled diabetic group correlated significantly with UAE (r = 0.45, P less than 0.001), whereas no significant correlation with auscultatory systolic values in the clinic was found (r = 0.21; P = 0.09). In conclusion, blood pressure in micro. as compared to normo. is not more labile but is elevated day and night without significant alteration of the diurnal rhythm. AMBP reflects the association between UAE and blood pressure more precisely than clinical measurements and may be preferable for identifying candidates for antihypertensive treatment.