Association between vitamin D levels and mortality in hemodialysis patients: a cohort study

Vitamin D Status and Treatment in ESKD: Links to Improved CKD-MBD Laboratory Parameters in a Real-World Setting

INTRODUCTION

Vitamin D insufficiency is common in patients who receive hemodialysis, yet there is no clear guidance regarding surveillance or treatment. We hypothesized that increasing 25(OH)D3 levels is associated with lower phosphate, parathyroid hormone (PTH), and alkaline phosphatase (ALP).

METHODS

Baseline 25(OH)D3 level was measured in all patients receiving in-center hemodialysis in June 2017. Laboratory parameters were measured every 6 (phosphate, calcium) or 12 weeks (25(OH)D3, PTH, ALP) until February 2021. In September 2018, a treatment algorithm of 50,000 IU weekly until sufficient followed by 50,000 IU monthly was suggested. Generalized linear mixed regression models including linear spline effects, a log link function, and random effects were used to examine the impact of increasing 25(OH)D3 levels on calcium, phosphate, ALP, and PTH.

RESULTS

Of 697 participants, 15% and 57% had vitamin D deficiency (25(OH)D3 <25 nmol/L) and insufficiency (between 25 and 74 nmol/L). Incorporating up to 7,272 observations, increasing 25(OH)D3 was associated with significantly decreasing PTH for 25(OH)D3 levels between 25 and 75 nmol/L regardless of vitamin D treatment. In an interaction model, the negative slope between 25(OH)D3 and PTH remained significant beyond 75 nmol/L in the absence of calcitriol. Increasing 25(OH)D3 was associated with significantly decreasing phosphate for 25(OH)D3 levels between 25 and 75 nmol/L regardless of vitamin D treatment and below 25 nmol/L in values of untreated patients. Calcium increased across the spectrum of 25(OH)D3 regardless of vitamin D treatment. Overall, 0.2% of 25(OH)D3 levels exceeded 250 nmol/L and 2.1% of calcium levels exceeded the normal range.

CONCLUSIONS

Vitamin D treatment in a real-world setting was safe and associated with lower PTH levels. Whether improved biochemical markers translate to a reduction in clinical endpoints warrants further study.

Vitamin D levels in the pre- and post-COVID-19 pandemic periods in pediatric patients with chronic kidney disease

Introduction

Vitamin D (VD) deficiency is common in children with chronic kidney disease (CKD) because of multiple factors. During the coronavirus disease 2019 (COVID-19) pandemic, it increased because of medicine shortage and no enough medical service for patients with non-COVID-19 diseases.

Objective

To analyze the effects of the COVID-19 pandemic-related lockdown on the serum levels and status of 25-hydroxyvitamin D3 (25-[OH]D) in children with CKD.

Materials and methods

This retrospective study included patients (6-18 years old) who were diagnosed with CKD stage 2-5 and routinely measured for serum VD levels between May 2019 and December 2022. Serum 25-(OH)D levels were measured before, during, and after the pandemic (2019, 2020-2021, and 2022, respectively). The daily dose of cholecalciferol supplementation and the readjustment (if required) were recorded.

Results

This study included 171 patients (median age: 12 years). Before the pandemic, the median serum VD level was 25.0 ng/mL (19.3% VD deficiency). Then, VD supplementation was adjusted to 400-1,200 UI daily in 98.8% (n = 169) of patients. During the pandemic, the median VD level decreased to 22.5 ng/mL (43.3% VD deficiency). Hence, the supplementation was readjusted, and after the pandemic, the level was 28.7 ng/mL (18.7% VD deficiency), indicating a statistically significant increase in serum VD levels from the prepandemic period (p = 0.007).

Conclusion

Decreased serum VD levels and increased VD deficiency frequency were observed in patients with CKD during the COVID-19 but improved after readjustment of supplementation.

Vitamin D Levels and the Risk of Posttransplant Diabetes Mellitus After Kidney Transplantation

Introduction:

Given the burden of posttransplant diabetes mellitus and the high prevalence of low vitamin D levels in kidney transplant recipients, it is reasonable to consider vitamin D as a novel and potentially modifiable risk factor in this patient population.

Research question:

To determine the association between 25- hydroxyvitamin D (25(OH)D) level and posttransplant diabetes among kidney transplant recipients. Design: In a multi-center cohort study of 442 patients who received a kidney transplant between January 1, 2005 and December 31, 2010, serum samples within one-year before transplant were analyzed for 25(OH)D levels. The association between 25(OH)D and posttransplant diabetes were examined in Cox proportional hazard models.

Results:

The median 25(OH)D level was 66 nmol/L. The cumulative probability of diabetes at 12-months by quartiles of 25(OH)D (< 42, 42 to 64.9, 65 to 94.9, and > 95 nmol/L) were 23.4%, 26.9%, 21.4%, and 15.6%, respectively. Compared to the highest 25(OH)D quartile, hazard ratios (95% CI) for the risk were 1.85 (1.03, 3.32), 2.01 (1.12, 3.60), 1.77 (0.96, 3.25) across the first to third quartiles, respectively. The associations were accentuated in a model restricted to patients on tacrolimus. When modeled as a continuous variable, 25(OH)D levels were significantly associated with a higher risk of diabetes (hazard ratio 1.06, 95% CI: 1.01, 1.13 per 10 nmol/L decrease).

Discussion:

Serum 25(OH)D was an independent predictor of posttransplant diabetes in kidney transplant recipients. These results may inform the design of trials using vitamin D to reduce the risk in kidney transplant recipients.