Unfavourable interaction of microalbuminuria and mildly reduced creatinine clearance on aortic stiffness in essential hypertension

The aim of our study was to assess the independent relationships of urinary albumin excretion rate (AER), of creatinine clearance (CrCl) and of their interaction with aortic stiffness in hypertensive patients without overt renal insufficiency. We studied 222 untreated nondiabetic essential hypertensives. In patients with reliable 24-h urine collections, AER and CrCl were determined. Microalbuminuria (MAU) was defined as an AER of 20 to 200microg/min. Aortic stiffness was assessed by measurement of carotid-femoral pulse wave velocity (c-f PWV). C-f PWV was higher in subjects with MAU than in those without it (p<0.001, even after adjustment for age, sex and mean arterial pressure) and in subjects with CrCl below 90ml/min/1.73m(2) when compared to those with greater values of CrCl (p=0.04 after correction for age, sex and mean arterial pressure). There was a significant interaction of MAU and reduced CrCl regarding c-f PWV (p=0.04). In multiple regression analysis, AER and CrCl remained independently associated with aortic stiffness (beta=0.22; p<0.001 and beta=-0.13; p=0.02, respectively). In essential hypertensive patients microalbuminuria and mildly reduced CrCl are related independently of each other with increased c-f PWV and exert a synergistic unfavourable effect on aortic stiffness.