What is the optimal level of vitamin D in non-dialysis chronic kidney disease population?

Abstract

AIMTo evaluate thresholds for serum 25(OH)D concentrations in relation to death, kidney progression and hospitalization in non-dialysis chronic kidney disease (CKD) population. METHODSFour hundred and seventy non-dialysis 3-5 stage CKD patients participating in OSERCE-2 study, a prospective, multicenter, cohort study, were prospectively evaluated and categorized into 3 groups according to 25(OH)D levels at enrollment (less than 20 ng/mL, between 20 and 29 ng/mL, and at or above 30 ng/mL), considering 25(OH)D between 20 and 29 ng/mL as reference group. Association between 25(OH)D levels and death (primary outcome), and time to first hospitalization and renal progression (secondary outcomes) over a 3-year followup, were assessed by Kaplan-Meier survival curves and Cox-proportional hazard models. To identify 25(OH)D levels at highest risk for outcomes, receiver operating characteristic (ROC) curves were performed. RESULTSOver 29 ± 12 mo of follow-up, 46 (10%) patients dead, 156 (33%) showed kidney progression, and 126 (27%) were hospitalized. After multivariate adjustment, 25(OH)D < 20 ng/mL was an independent predictor of all-cause mortality (HR = 2.33; 95%CI: 1.10-4.91; P = 0.027) and kidney progression (HR = 2.46; 95%CI: 1.63-3.71; P < 0.001), whereas the group with 25(OH)D at or above 30 ng/mL did not have a different hazard for outcomes from the reference group. Hospitalization outcomes were predicted by 25(OH) levels (HR = 0.98; 95%CI: 0.96-1.00; P = 0.027) in the unadjusted Cox proportional hazards model, but not after multivariate adjusting. ROC curves identified 25(OH)D levels at highest risk for death, kidney progression, and hospitalization, at 17.4 ng/mL [area under the curve (AUC) = 0.60; 95%CI: 0.52-0.69; P = 0.027], 18.6 ng/mL (AUC = 0.65; 95%CI: 0.60-0.71; P < 0.001), and 19.0 ng/mL (AUC = 0.56; 95%CI: 0.50-0.62; P = 0.048), respectively. CONCLUSION 25(OH)D < 20 ng/mL was an independent predictor of death and progression in patients with stage 3-5 CKD, with no additional benefits when patients reached the levels at or above 30 ng/mL suggested as optimal by CKD guidelines. Core tip: This study examines the prognosis value of 25(OH)D levels on death, chronic kidney disease (CKD) progression, and hospitalization in a cohort of 3-5 stage CKD subjects not on dialysis. The main findings were the predictor value of vitamin D deficiency (< 20 ng/ mL), but not insufficiency (< 30 ng/mL), for the 3-year incidence of death and CKD progression, which remained significant after multivariate adjustments. These results could highlight the need for a revision of the current guidelines, which have defined optimal vitamin D status at ≥ 30 ng/mL based on levels required to suppress parathyroid hormone, as opposed to our study, which evaluates thresholds for serum 25(OH)D concentrations in relation to "hard" endpoints.

Raising awareness on the therapeutic role of cholecalciferol in CKD: a multidisciplinary-based opinion

“…The pleiotropic effects of vitamin D fit well with the potential benefits of multifactorial nephrology care in CKD in non-dialysis as in dialysis setting [ 43 – 46 ]. To date, however, we have no solid data, that is, generated by well-designed controlled trials, demonstrating that the administration of native vitamin D in CKD patients ameliorates “hard” clinical outcomes besides and beyond the metabolic profile [ 47 – 51 ].…”

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

“…risk of death, kidney progression, and hospitalization, with the respective concentrations of 17.4 ng/mL (43.4 nmol/L), 18.6 ng/mL (46.4 nmol/L), and 19.0 ng/mL (47.4 nmol/L), denoting the highest risk prediction sensitivity and specificity 171. …”

A Review of the Potential Benefits of Increasing Vitamin D Status in Mongolian Adults through Food Fortification and Vitamin D Supplementation

“…A prospective 3-year study of 470 unsupplemented non-dialysis patients in Spain with stage 3–5 CKD reported that those with baseline 25(OH)D values between 20 and 30 ng/mL had better survival, lower hospitalization, and better composite renal endpoints than those with lower or higher baseline concentrations [51], but found no additional benefits from raising serum 25(OH)D concentration to >30 ng/mL.…”