Endocrine Abstracts

JOINT1407

Introduction: The complex pathophysiology of mineral-bone disorders in chronic kidney disease (CKD) starts very early, when calcium and phosphorus are deposited in the walls of blood vessels and heart valves instead of bones, increasing the cardiovascular (CV) risk in these patients. An additional aggravating circumstance is the onset of secondary hyperparathyroidism, which, in addition to increasing CV risk, also contributes to increasing the risk of bone fractures. In this vicious circle, one of the biggest treatment challenges is how to regulate serum calcium levels, bearing in mind that calcium substitution with necessary vitamin D leads to an increase in the product of serum calcium and phosphate (CaxP), which contributes to the development of vascular calcifications and CV risk.

Objective: To determine the serum calcium values in patients with CKD in relation to the disease stage and to examine the relation with other parameters of mineral-bone disorder and the carotid intima media thickness (IMT) as well, as indicators of the early process of atherosclerosis.

Methods: This study was conducted as a cross-sectional study. It included 88 patients with all stages of CKD. The patients were classified into stages according to the estimated glomerular filtration rate (eGFR) according to MDRD (Modification of Diet in Renal Disease Formula). The carotid IMT was measured in accordance with the recommendations of the Mannheim Consensus.

Results: Of tested individuals 56% were women, average age of 63. The mean value of calcium was 2.35±0.21 mmol/l and stayed within the reference values in all stages of CKD, while the mean value of IMT was 1.10±0.20 mm with pathological values already identified from stage 2 of CKD. The CaxP values were positively correlated with serum creatinine (r=0.65, P<0.001). The pathological values of parathyroid hormone (PTH) were registered from stage 3 of CHD and were positively correlated with CaxP (r=0.46, P<0.001). The patients with PTH >600 ng/l had significantly higher values of serum calcium and phosphate, CaxP and IMT. The IMT was positively correlated with CaxP (r=0.25, P<0.5), PTH (r=0.24, P<0.5) and creatinine (r=0.28, P<0.01).

Conclusion: Advanced CKD is accompanied by an increase in calcium and phosphate products with the onset of the atherosclerosis, which is why careful monitoring of the mineral status of these patients is of significance for their outcome. A difficulty in correcting the mineral status would be a reason to consider a bone biopsy and adjustment of the treatment approach.