AMBULATORY BLOOD-PRESSURE AND MICROALBUMINURIA IN ESSENTIAL-HYPERTENSION - ROLE OF CIRCADIAN VARIABILITY

Objective: To assess the relationship of subclinical urinary albumin e xcretion with ambulatory and circadian variability of blood pressure. Design and methods: Patients with essential hypertension (82 males and 59 females, mean+/-SD age 38.9+/-7.3 years) who had never been previo usly treated for hypertension were included in the study. Patients wit h nephropathy or diabetes mellitus, hyperglycemia >120 mg/dl, glomerul ar filtration rate <80 ml/min per 1.73 m(2), urinary tract infection a nd positive dipstick for albumin or glucose were excluded, Twenty-four -hour ambulatory blood pressure monitoring on a regular working day us ing an oscillometric device was performed. Twenty-four-hour urinary al bumin excretion was measured on two separate days using an immunonephe lometric assay. Results: Microalbuminuric patients (urinary albumin ex cretion 30-300 mg/24 h, n = 31) had significantly higher mean ambulato ry systolic blood pressure (SBP) and diastolic blood pressure (DBP) th an those with normoalbuminuria (urinary albumin excretion <30 mg/24 h, n = 96) during the 24-h, daytime (0800-2200 h) and night (2400-0600 h ) periods, whereas for office blood pressure only DBP was significantl y higher. Urinary albumin excretion was positively correlated with the means of SBP and DBP. Multiple regression analysis similarly confirme d that DBP during daytime was positively and day:night ratio of DBP in versely associated with urinary albumin excretion independent of age, sex and other parameters of ambulatory blood pressure. Conclusions: In conclusion, the present study indicates that, in middle-aged essentia l hypertensive patients, the presence of microalbuminuria is a marker for the presence of higher values of blood pressure throughout a 24-h period.