[Relationship between the vitamin D supply and some protein fractions in patients with chronic kidney disease]

Introduction: Chronic kidney disease is often associated with severe vitamin D deficiency. Diagnosis is based on the serum 25-hydroxyvitamin D level, which is routinely measured mainly by the immunoassay. This method depends on the level of vitamin D-binding and other proteins in the sample. Objective: To study the relationship between serum proteins and vitamin D supply in vitamin D3 naive patients with chronic kidney disease. Methods: Total 25-hydroxyvitamin D, vitamin D-binding protein, calcium, total protein, albumin, and electrophoretic protein fractions were measured in the serum of 103 chronic kidney disease patients (30 non-dialysis, 36 peritoneal dialysis, 37 hemodialysis). Intact parathormone levels were also determined using 2nd- and 3rd-generation methods. Results: Sufficient vitamin-D supply was not found in any cases, 87% of non-dialysis, 86% of hemodialysis, and all peritoneal dialysis patients were vitamin D deficient. Outside the reference range values for alpha-1- (18%), beta- (22%) globulin and albumin/globulin (19%) ratio occurred significantly less frequently in dialysis patients than in non-dialysis patients, in contrast to vitamin D-binding protein (37%). Lower total 25-hydroxyvitamin D, calcium and total protein, gamma-globulin, albumin/globulin values, higher alpha-1,2-globulin and vitamin D-binding protein levels were found in peritoneal dialysis patients. Negative correlation between total 25-hydroxyvitamin D and intact parathormone, with both methods, was confirmed in peritoneal dialysis patients. This relationship was significant only by the 3rd-generation method in hemodialysis patients. Conclusion: In chronic kidney disease patients, especially in those with peritoneal dialysis, vitamin D deficiency worsens after started dialysis, therefore, they need higher doses of vitamin D3. High alpha-1 globulin level is associated with vitamin D deficiency in both dialysis and non-dialysis cases. Dialysis treatment, particularly peritoneal dialysis, affects the deviation of the vitamin D-binding protein and other serum proteins from the reference ranges. Giving native vitamin D is also important in the treatment of secondary hyperparathyroidism. To verify this in hemodialysis, the use of the 3rd-generation method is recommended. Orv Hetil. 2024; 165(30): 1154–1165.