Cholecalciferol vs. Small Doses of Alfacalcidol vs. Placebo in Chronic Kidney Disease Patients on Hemodialysis: A Randomized Parallel Group Study

Does native vitamin D, or active vitamin D modulate the neutralising antibody responses to COVID-19 vaccination in haemodialysis patients?

INTRODUCTION

Several studies have reported that patients with low levels of Vitamin D3 have impaired responses to vaccination, including COVID-19 vaccines, so we reviewed the response to COVID-19 vaccination in haemodialysis patients, who typically have reduced Vitamin D3 levels.

METHODS

The inhibitory antibody (IC50) responses to several COVID-19 variants following vaccination in a cohort of United Kingdom haemodialysis patients receiving two vaccinations between March 2021 and May 2021 were reviewed.

RESULTS

A total of 183 haemodialysis patients, 65.5% male, mean age 65.6 ± 14.1 years, 46.4% diabetic, 42.1% white ethnicity, body mass index 26.9 ± 6.5 kg/m2 dialysis vintage 36.2 (18.3-69.3) months were studied. Following the first vaccination, the median IgG microneutralisation IC50 response was undetectable for all variants (wild-type, alpha, beta and delta). Follow-up after the second vaccination showed that the microneutralisation response to all variants increased and was greater for the wild-type variant compared to alpha, beta and delta, all p < 0.001, There were no differences comparing the IC50 responses according to 25-Vitamin D3 levels, and the prescription of activated Vitamin D. Although patients who had previously tested positive for COVID-19 prescribed higher doses of alfacalcidol had higher seroprotection responses to the alpha (χ2 = 15, p = 0.002) and beta variants. (χ2 = 13, p = 0.005).

CONCLUSIONS

The response to COVID-19 vaccination was reduced in our elderly haemodialysis patients compared to younger less frail patients, however there was no overall demonstrable effect of either 25-Vitamin D3 levels or the prescription of activated forms of Vitamin D on the immune response following vaccination against COVID-19, unless patients had previously tested positive for COVID-19.

The Efficacy and Safety of High-Dose Cholecalciferol Therapy in Hemodialysis Patients

Vitamin D deficiency and insufficiency are highly prevalent in CKD, affecting over 80% of hemodialysis (HD) patients and requiring therapeutic intervention. Nephrological societies suggest the administration of cholecalciferol according to the guidelines for the general population. The aim of the observational study was to evaluate the efficacy and safety of the therapy with a high dose of cholecalciferol in HD patients with 25(OH)D deficiency and insufficiency to reach the target serum 25(OH)D level > 30 ng/mL. A total of 22 patients (16 M), with an average age of 72.5 ± 13.03 years and 25(OH)D concentration of 13.05 (9.00-17.90) ng/mL, were administered cholecalciferol at a therapeutic dose of 70,000 IU/week (20,000 IU + 20,000 IU + 30,000 IU, immediately after each dialysis session). All patients achieved the target value > 30 ng/mL, with a mean time of 2.86 ± 1.87 weeks. In the first week, the target level of 25(OH)D (100%) was reached by 2 patients (9.09%), in the second week by 15 patients (68.18%), in the fourth week by 18 patients (81.18%), and in the ninth week by all 22 patients (100%). A significant increase in 1,25(OH)2D levels was observed during the study. However, only 2 patients (9.09%) achieved a concentration of 1,25(OH)2D above 25 ng/mL-the lower limit of the reference range. The intact PTH concentrations remained unchanged during the observation period. No episodes of hypercalcemia were detected, and one new episode of hyperphosphatemia was observed. In conclusion, our study showed that the administration of a high-therapeutic dose of cholecalciferol allowed for a quick, effective, and safe leveling of 25(OH)D concentration in HD patients.

Performance Status Modifies the Association Between Vitamin D Receptor Activator and Mortality or Fracture: A Prospective Cohort Study on the Japanese Society for Dialysis Therapy (JSDT) Renal Data Registry

Immobilization osteoporosis is characterized by excess bone resorption. Vitamin D receptor activators (VDRA) might have adverse effects in immobilized patients. The objective of this study was to elucidate the impact of performance status (PS) on the associations between VDRA use and outcomes among hemodialysis patients. This is a prospective cohort study. Adults on hemodialysis in the Japanese Society for Dialysis Therapy (JSDT) Renal Data Registry were included. Exposure of interest was the use of VDRA. Outcomes were all-cause mortality and hip fracture. Associations between VDRA use and mortality or hip fractures were examined by Cox and Poisson regression analyses, respectively. Among 208,512 subjects, 128,535 were on VDRA. Poor PS was associated with higher calcium (Ca), lower parathyroid hormone, and higher alkaline phosphatase levels. The association between higher Ca levels and VDRA use was stronger among those with poor PS (p interaction 0.007). Adjusted hazard ratio (HR) (95% confidence interval [CI]) for mortality and incidence rate ratio (IRR) for hip fracture was 1.02 (95% CI, 0.99-1.05) and 0.93 (0.86-1.00) among users of VDRA, respectively. The VDRA use was associated with lower mortality and incidence of hip fractures among subjects with good PS but not among subjects with poor PS (p interaction 0.03 and 0.05). Effect modification by PS was observed for cardiovascular (CV) mortality but not for non-CV mortality. In conclusion, VDRA use was associated with better outcomes only among those with good PS. These results suggest that bone and mineral disorders among hemodialysis patients should be treated differently, depending on their performance status. © 2022 American Society for Bone and Mineral Research (ASBMR).

Recent advances of gut microbiota in chronic kidney disease patients

Chronic kidney disease (CKD) is a worldwide public health issue and has ultimately progressed to an end-stage renal disease that requires life-long dialysis or renal transplantation. However, the underlying molecular mechanism of these pathological development and progression remains to be fully understood. The human gut microbiota is made up of approximately 100 trillion microbial cells including anaerobic and aerobic species. In recent years, more and more evidence has indicated a clear association between dysbiosis of gut microbiota and CKD including immunoglobulin A (IgA) nephropathy, diabetic kidney disease, membranous nephropathy, chronic renal failure and end-stage renal disease. The current review describes gut microbial dysbiosis and metabolites in patients with CKD thus helping to understand human disease. Treatment with prebiotics, probiotics and natural products can attenuate CKD through improving dysbiosis of gut microbiota, indicating a novel intervention strategy in patients with CKD. This review also discusses therapeutic options, such as prebiotics, probiotics and natural products, for targeting dysbiosis of gut microbiota in patients to provide more specific concept-driven therapy strategy for CKD treatment.