Abstract: Objective To investigate the relationship between ambulatory arterial stiffness index (AASI) derived from blood pressure monitoring and early signs of renal damage in patients with primary hypertension． Methods 74 primary hypertensive outpatients were divided into two groups according to their AASI values: normal AASI group (AASI≤0.51, n=40) and high AASI group (AASI>0.51, n=32). The urinary micro-albumin, glomerular filtration rates (GFR) were measured and compared. The relationship between AASI and micro-albumin, GFR were tested with Pearson correlation and multiple Logistic regression. Results Compared with those in the normal AASI group, the patients in high AASI group showed a higher level of urinary microalbumin (P<0.05) and a reduction in GFR (P<0.01). AASI was positively correlated with urinary microalbumin （r=0.32, P<0.001）, and negatively correlated with GFR （r=0.44, P<0.001）. After adjusting the potentially confounding variables, the odd ratio (OR) of AASI to renal damage was 2.18 （P=0.008，95%CI：1.76～4.34）. Conclusion The increase of AASI is associated with early signs of renal damage in patients with primary hypertension.

Key words: hypertension, ambulatory arterial stiffness index(AASI), renal damage