Factors Associated with Vascular Stiffness: Cross-Sectional Analysis from the Chronic Renal Insufficiency Standards Implementation Study

BACKGROUND: Vascular stiffness is associated with increased cardiovascular risk. This study aimed to identify factors associated with vascular stiffness in a cohort of chronic kidney disease (CKD) patients. METHODS: The Chronic Renal Insufficiency Standards Implementation Study is a prospective epidemiological study of CKD patients not on dialysis, who are managed in a clinic setting. Phenotypic parameters were collected annually, and vascular stiffness was assessed using augmentation index (AI). Cross-sectional analysis was performed across quintiles of AI to evaluate factors associated with vascular stiffness. RESULTS: Mean patient age was 66.1 +/- 14.1 years and estimated glomerular filtration rate (eGFR) was 31.2 +/- 5.7 ml/min. Corrected calcium was 2.26 +/- 0.2 SD mmol/l, phosphate 1.2 +/- 0.4 SD mmol/l and intact parathyroid hormone 94 +/- 96 SD pg/ml; 18.3% of patients had cardiovascular disease. Increased age and systolic blood pressure were associated with increased AI (all p < 0.001). No statistical association was present between AI and eGFR, intact parathyroid hormone, phosphate or protein excretion. CONCLUSION: This study identified blood pressure as a potentially modifiable risk factor associated with AI, whereas eGFR was not associated with increased AI in a population of CKD stage 3-5 patients. Further knowledge of factors which influence progression of vascular stiffness will be important in risk quantification and management.