Association between Albumin : Creatinine ratio and 24-hour ambulatory blood pressure in essential hypertension

Microalbuminuria (MAU) is often found in essential hypertension (EH) and re presents a sign of renal and cardio-vascular damage. In the present study, we aimed to look at the association between ambulatory blood pressure (BP) and urinary albumin excretion (UAE), We studied 140 patients aged 50.1 +/- 11.6 years referred for 24-h ambulatory blood pressure monitoring (ABPM) an d, separately 46 untreated subjects with newly diagnosed EH. Urinary albumi n excretion was evaluated by determination of the albumin-to-creatinine rat io (ACR) in the first voided morning urine sample taken the same day as the ABPM was started. According to the ACR, patients were categorized as havin g nornoalbuminuria (ACR <1.5 mg/mmol), borderline MAU (1.5 <less than or eq ual to> ACR <3.0 mg/mmol), and overt MAU (ACR <greater than or equal to>3.0 mg/mmol). Mean ACR was significantly higher in hypertensive than normotensive individ uals (2.17 +/- 2.67 mg/mmol and 1.72 +/- 2.97 mg/mmol, respectively, P = .0 12), Average 24-h, daytime and nighttime systolic BP and diastolic BP were lower in patients with normoalbuminuria than in the other two groups and di d not differ among the two microalbuminuric groups. Univariate regression a nalysis showed a close relationship between ACR and ambulatory BP, Strong c orrelation between BP and ACR in the normoalbuminuric and borderline microa lbuminuric range was also obtained in the group of 46 newly diagnosed hyper tensive patients. In conclusion, the threshold level of ACR greater than or equal to3.0 mg/mm ol currently used to define microalbuminuria may be not applicable to EH. I nstead, a threshold level of ACR greater than or equal to1.5 mg/mmol may be more. appropriate, (C) 2001 American Journal of Hypertension, Ltd.