Subclinical cardiovascular disease markers and vitamin D deficiency in non-dialysis chronic kidney disease patients.

INTRODUCTION: Since 25-hydroxyvitamin D (25(OH)D) deficiency has been linked to an increased risk for cardiovascular disease (CVD) in the hemodialysis population, we aimed to determine the relationship between serum 25(OH)D level and markers of subclinical CVD in non-dialysis chronic kidney disease (CKD) patients.

MATERIAL AND METHODS: This cross-sectional, single-center study prospectively enrolled 87 clinically stable CKD patients (median age: 61 (57-66) years, 51% male, median estimated glomerular filtration rate (eGFR): 32 (27-37) ml/min). Five markers of subclinical CVD were assessed: intima-media thickness, abdominal aortic calcifications (AAC) using the Kauppila score, cardio-ankle vascular index, ankle-brachial index (ABI) and interventricular septum thickness.

RESULTS: Vascular (37%), glomerular (23%) and interstitial (18%) nephropathies were the main causes of CKD. 25(OH)D had a median value of 14 (12.5-17.1) ng/ml, and its levels decreased with eGFR (rs = 0.19; p = 0.04). Patients with 25(OH)D deficiency (54%) were older, had a higher serum alkaline phosphatase level, lower ABI and higher AAC score. There were no differences between the two groups regarding other traditional or non-traditional risk factors for atherosclerosis. The association between subclinical CVD markers and 25(OH)D was further evaluated in multivariable binomial logistic regression models adjusted for CV risk factors. Lower 25(OH)D level was retained as an independent predictor only for pathological ABI.

CONCLUSIONS: This is the first study to evaluate the relationship between a large set of subclinical CVD markers and 25(OH)D deficiency in non-dialysis CKD patients. We found that hypovitaminosis D is associated with subclinical peripheral arterial disease, independently of other cardiovascular risk factors.