[24-hour blood pressure monitoring and albumin excretion in urine in hypertension].

BACKGROUND AND OBJECTIVES

Microalbuminuria, a subclinical increase of albumin excretion in urine, is a novel recognized risk factor for atherosclerosis in essential hypertension. This study aimed to look at the association between ambulatory blood pressure and urinary albumin excretion (UAE) in hypertensive subjects.

MATERIAL AND METHODS

140 patients aged 50.1 +/- 11.6 years, referred for 24-hour ambulatory blood pressure monitoring (ABPM), were studied. A separate analysis was performed in 46 persons with newly diagnosed and untreated essential hypertension. Albumin excretion was evaluated by determining the albumin/creatinine ratio (ACR) in the first voided morning urine sample. According to the ACR, patients were categorized as having normoalbuminuria (ACR < 1.5 mg/mmol), borderline microalbuminuria (1.5 < or = ACR < 3.0 mg/mmol) and overt microalbuminuria (ACR > or = 3.0 mg/mmol).

RESULTS

ACR was significantly higher in hypertensive than in normotensive individuals (2.17 +/- 2.67 and 1.72 +/- 2.97 mg/mmol respectively, p = 0.012). Average 24-hour, daytime and nighttime systolic as well as diastolic blood pressures were lower in patients with normoalbuminuria than in the other two groups and did not differ among the two microalbuminuric groups. A close relationship between ACR and ambulatory BP was observed, even for the subgroup of newly diagnosed and untreated hypertensive patients.

INTERPRETATION

A close relationship is observed between ambulatory blood pressures and albumin excretion rates in the microalbuminuric and normoalbuminuric range. Further studies are needed to assess the threshold level of ACR when screening for microalbuminuria in hypertensive patients.