The value of symmetrical ambulatory arterial stiffness index should be noted in prediction of early renal impairment in patients with essential hypertension

Abstract

Objective To investigate the predictive value of symmetrical ambulatory arterial stiffness index (S-AASI) in detecting early renal impairment of patients with essential hypertension. Methods Totally 245 consecutive out-patients were confirmed with essential hypertension, and were divided into group A (56 cases), group B (64 cases), group C (72 cases), and group D (53 cases) according to the quartile of S-AASI. The combination testing of serum cystatin C, serum β2-microglobulin as well as urine microalbumin to creatinine ratio were implemented as laboratory diagnosis index of renal impairment in early stage and 109 essential hypertension patients were diagnosed with early renal impairment. The parameters were compared among 4 groups. Pearson correlation analysis and partial correlation analysis were performed to confirm the relationship between the markers of early renal impairment and S-AASI. The predictive value of S-AASI to detect early renal injury was evaluated by analyzing Receiver Operating Characteristic (ROC) curve. Results With the rising of S-AASI, age as well as 24 hours mean systolic blood pressure (24 h SBP), serum cystatin C, serum β2-microglobulin, urine microalbumin to creatinine ratio and the incidence rate of early renal injury went notably higher while estimated glomerular filtration rate (eGFR) decreased significantly. After controlling for age, correlation test showed S-AASI was positively correlated with24hSBP, serum cystatin C, serumβ2-microglobulin, urine microalbumin to creatinine ratio(r=0.392, 0.627, 0.514 and 0.643 respectively, P<0.05)and negatively correlated with eGFR(r=-0.312, P<0.05). The 24 hours mean diastolic blood pressure (24 h DBP) was uncorrelated with S-AASI. Area under ROC curve of S-AASI for diagnosis of hypertensive renal impairment was 0.885. The critical value of S-AASI was 0.17, the sensitivity, specificity, positive predictive value, and negative predictive value were 92.7%, 65.2%, 68.5%, and 91.7%, respectively. Conclusions When S-AASI was detected above 0.17, patients with hypertension had a higher risk of renal impairment. Higher S-AASI was correlated with worse early renal impairment laboratory indexes. The predictive accuracy of S-AASI for early hypertensive renal impairment was medium. Key words: Arteriosclerosis; Hypertension/CO; Kidney diseases/CO; Forecasting