Vitamin D Insufficiency and Deficiency in Chronic Kidney Disease

Abstract

Background: Kidney disease has been identified as a risk factor for vitamin D deficiency in hospitalized patients, and low levels of 25-hydroxyvitamin D have been suggested to be a risk factor for hyperparathyroidism in patients with chronic kidney disease (CKD). However, little is known about the magnitude of vitamin D deficiency in patients with CKD living in the United States. Methods: In this regard, we examined the levels of 25(OH)D in 43 patients with CKD and serum creatinine between 1 and 5 mg/dl (calculated glomerular filtration rate 111–11 ml/min per 1.73 m²) as well as in 103 patients undergoing hemodialysis. Results: In the predialysis patients, we found that 37 of the 43 patients (86%) had suboptimal levels of vitamin D (<30 ng/ml). Regression analysis indicated that there was a negative correlation between 25(OH)D and intact parathyroid hormone (PTH). Alkaline phosphatase showed a similar but less sensitive relationship. Serum albumin levels correlated with 25(OH)D levels. In contrast to findings reported in normal individuals, the levels of calcitriol correlated with those of 25(OH)D in the patients with CKD. In the group undergoing maintenance hemodialyis, we found that 97% of the patients had vitamin D levels in the suboptimal range, and there was no correlation of 25(OH)D levels with either PTH or serum albumin values. These data indicate that vitamin D insufficiency and deficiency are highly prevalent in patients with CKD and may play a role in the development of hyperparathyroidism. The functional significance of low levels of 25(OH)D in patients with stage 5 CKD remains to be determined.

Vitamin D, a modulator of musculoskeletal health in chronic kidney disease

“…Other experts, however, estimate that 25(OH)D > 20 ng/mL (50 nmol/L) are adequate to suppress PTH 157. Although there is also an inverse relationship between 25(OH)D and PTH levels in CKD patients,161, 162 this pathophysiological definition is possibly inappropriate in these patients, given that PTH secretion is influenced by several factors related to the uremic state (such as hypocalcaemia or hyperphosphatemia), independently of 25(OH)D levels 163

Fracture prevention.

…”

Effect of nutritional vitamin D preparations on parathyroid hormone in patients with chronic kidney disease

“…The positive correlation between serum 25(OH)D and 1,25(OH) 2 D levels was documented only in VitD insufficient CKD patients, but not in persons with normal renal function [30,45]. 25(OH)D probably exhibits biologic actions affecting patients with CKD differently compared with normal individuals [46].…”

“…Studies have reported varying prevalence rates of VitD deficiency in predialysis and dialysis patients ranging between 70 and 98% [23,27] and 51 and 100% [28,29], respectively. Patients with severe proteinuria have the lowest 25(OH)D levels (probably because of losses of protein-bound 25(OH)D) [30], while patients on PD have significantly lower levels of 25(OH)D compared to those on HD (probably because of increased 25(OH)D losses in the peritoneal effluent) [31].…”

FGF-23: estado da arte

“…55 Another unanswered question is whether FGF-23 levels could be modulated by P binders, such as calcium acetate or sevelamer hydrochloride. In the case that therapeutic strategy proves to be feasible, probably it could benefit patients with CKD, mainly at earlier stages.…”