Vitamin D Deficiency Due to Chronic Kidney Disease

The goal of this observational study is to learn about the effects of cholecalciferol administration, according to guidelines for the general population, on laboratory parameters of Chronic Kidney Disease-Mineral and Bone Disorder in dialysis patients, depending of the attained levels of vitamin D (25OH)D). The main question it aims to answer is: How does cholecalciferol affect calcium and phosphate metabolism parameters depending on the achieved levels of 25(OH)D? Participants taking cholecalciferol as part of their regular medical care for CKD-MBD will have the laboratory result parameters observed for up to 4 years.