ASSOCIATION BETWEEN VITAMIN D STATUS AND VASCULAR ENDPOINTS IN CHRONIC KIDNEY DISEASE: A SECONDARY POST-HOC ANALYSIS OF IMPROVE-CKD

ASSOCIATION BETWEEN VITAMIN D STATUS AND VASCULAR ENDPOINTS IN CHRONIC KIDNEY DISEASE: A SECONDARY POST-HOC ANALYSIS OF IMPROVE-CKD

Wing Chi Gigi Yeung^1,2,3, NIGEL D. TOUSSAINT^4,5, NICOLE LIOUFAS^4,5, CARMEL M. HAWLEY^6,7,8, ELAINE M. PASCOE⁹, GRAHAME J. ELDER^10,11,12, SUNIL V. BADVE^2,3,13, IMPROVE-CKD TRIAL INVESTIGATORS

¹Department of Nephrology, Wollongong Hospital, Wollongong, NSW, Australia
²The George Institute for Global Health, Sydney, NSW, Australia
³Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
⁴Department of Nephrology, The Royal Melbourne Hospital, Melbourne, VIC, Australia
⁵Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
⁶Translational Research Institute, Brisbane, QLD, Australia
⁷Department of Nephrology, Princess Alexandra Hospital, Brisbane, QLD, Australia
⁸Australasian Kidney Trials Network, The University of Queensland, Brisbane, QLD, Australia
⁹Centre for Health Services Research, The University of Queensland, Brisbane, QLD, Australia
¹⁰School of Medicine, University of Notre Dame, Sydney, NSW, Australia
¹¹Skeletal Biology Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
¹² Department of Nephrology, Westmead Hospital, Sydney, NSW, Australia
¹³Department of Nephrology, St George Hospital, Sydney, NSW, Australia

Abstract

Aim:
To assess the relationship between vitamin D status, arterial stiffness and aortic calcification in patients with chronic kidney disease (CKD) stage 3b-4

Background:
Cardiovascular disease is the leading cause of death in CKD patients. The excess cardiovascular risk seen in CKD may be partly explained by abnormalities in mineral metabolism and vascular calcification. Vitamin D deficiency is involved in the pathogenesis of CKD Mineral Bone Disorder and may also play a more direct role in vascular function.

Methods:
A cross-sectional analysis was performed using baseline data from the IMPROVE-CKD study cohort. Patients were divided into two groups based on presence of vitamin D deficiency, defined as 25-hydroxyvitamin D (25[OH]D) <50 nmol/L. Clinical and laboratory parameters were compared between the two groups. Univariable and multivariable linear regression analyses were performed to assess the association between 25(OH)D levels and pulse wave velocity (PWV), augmentation index (AIx) and abdominal aortic calcification (as measured by the Agatston score). Results: 208 patients had baseline 25(OH)D levels available for analysis. Mean 25(OH)D in the two groups were 82.8 and 36.2 nmol/L respectively. 25(OH)D deficiency was associated with diabetes mellitus (p = 0.02), cardiovascular disease (p = 0.02), serum triglycerides (p = 0.01) and serum calcium (p<0.01). In univariable analysis, 25(OH)D levels were negatively correlated with PWV (β = -0.03, p = 0.03) and positively correlated with AIx (β = 0.06, p = 0.045), but not with Agatston score. After adjusting for relevant confounders in the multivariable regression analyses, the associations between 25(OH)D, PWV and AIx were no longer significant. Conclusions: Baseline 25(OH)D levels were not associated with markers of arterial stiffness and aortic calcification in patients with CKD stage 3b-4.

Biography

Dr Wing Chi Gigi Yeung is a nephrologist at Wollongong Hospital and is currently undertaking a PhD at The George Institute for Global Health in the area of CKD-MBD.