Native vitamin D in pre-dialysis chronic kidney disease

Accumulated LPS induced by colitis altered the activities of vitamin D-metabolizing hydroxylases and decreased the generation of 25-hydroxyvitamin D

It is generally accepted that low vitamin D (VD) levels are associated with a high prevalence factor for Inflammatory bowel disease (IBD). IBD patients have observed higher levels of lipopolysaccharide (LPS), ALT, and AST than healthy people. Gut-derived LPS causes inflammatory injury in the liver and kidney. The VD-metabolizing mechanism is involved in the liver and kidney, which means IBD might impact VD metabolism. However, whether IBD affects VD metabolism has not been studied. In vitro LPS resulted in decreased CYP2R1 in liver cells as well as decreased CYP27B1 and increased CYP24A1 in kidney cells, revealing that LPS changed the activities of several hydroxylases. Mice with acute colitis had an increased LPS in serum and liver with mild hepatic injuries, while mice with chronic colitis had a significant elevation of LPS in serum, liver, and kidney with hepatorenal injuries. Thus, the liver hydroxylase for VD metabolism would be the first to be affected in IBD. Consequently, serum 25-hydroxyvitamin D declined dramatically with a significant elevation of 24,25-dihydroxyvitamin D and 1,24,25-trihydroxyvitamin D. Unchanged serum levels of 1,25-dihydroxyvitamin D might be the result of other factors in vivo. In acute colitis, a small dosage (4 IU/day) of cholecalciferol could protect the colon, decrease the serum level of LPS, and finally increase serum 25-hydroxyvitamin D. However, this improvement of cholecalciferol was fading in chronic colitis. These results suggested that VD supplementations for preventing and curing IBD in the clinic should consider hepatorenal hydroxylases and be employed as soon as possible for a better outcome.

Are There Any Pleiotropic Benefits of Vitamin D in Patients With Diabetic Kidney Disease? A Systematic Review of Randomized Controlled Trials

Background

Type 2 diabetes (T2D) and kidney disease are risk factors for vitamin D deficiency. Native forms of vitamin D have a lower risk of hypercalcemia than calcitriol, the active hormone. The enzyme responsible for activating native vitamin D is now known to be expressed throughout the body; therefore, native vitamin D may have clinically relevant effects in many body systems.

Objective

The objective of this systematic review was to examine the effect of native vitamin D supplementation on clinical outcomes and surrogate laboratory measures in patients with T2D and diabetic kidney disease (DKD).

Design

Systematic review.

Setting

Randomized controlled trials (RCTs) conducted in any country.

Patients

Adults with T2D and DKD receiving supplementation with any form of native vitamin D (eg, ergocalciferol, cholecalciferol, calcifediol).

Measurements

Clinical outcomes and surrogate clinical and laboratory measures reported in each of the trials were included in this review.

Methods

The following databases were searched from inception to January 31, 2023: Embase, MEDLINE, Cochrane CENTRAL, Web of Science, ProQuest Dissertations and Theses, and medRxiv. Only RCTs examining supplementation with a native vitamin D form with a control or placebo comparison group were included. We excluded studies reporting only vitamin D status or mineral metabolism parameters, without any other outcomes of clinical relevance or surrogate laboratory measures. Study quality was evaluated using the Cochrane risk-of-bias tool (RoB2). Results were synthesized in summary tables for each type of outcome with the P values from the original studies displayed.

Results

Nine publications were included, corresponding to 5 separate RCTs (377 participants total). Mean age ranged from 40 to 63. All trials administered vitamin D3. Intervention groups experienced improvements in vitamin D status and a reduction in proteinuria in 4 of the 5 included RCTs. There was a decrease in low-density lipoprotein and total cholesterol in the 2 trials in which they were measured. Improvements in bone mass, flow-mediated dilation, and inflammation were also reported, but each was only measured in 1 RCT. Effects on glucose metabolism, high-density lipoprotein, triglycerides, blood pressure, oxidative stress, and kidney function were mixed. No serious adverse effects were reported.

Limitations

Limitations include the small number of RCTs and lack of information on the use of drugs that affect measured outcomes (eg, proteinuria-lowering renin-angiotensin-aldosterone system inhibitors and lipid-lowering medication) in most studies. Our study is also limited by the absence of a prestudy protocol and registration.

Conclusions

Native vitamin D is a safe treatment that improves vitamin D status in patients with DKD. Vitamin D may modify proteinuria and lipid metabolism in DKD, but further well-designed trials that include well-established treatments are necessary. Overall, there is limited evidence for beneficial pleiotropic effects of vitamin D in patients with DKD.

Calcifediol: Mechanisms of Action

Due to its essential role in calcium and phosphate homeostasis, the secosteroid hormone calcitriol has received growing attention over the last few years. Calcitriol, like other steroid hormones, may function through both genomic and non-genomic mechanisms. In the traditional function, the interaction between the biologically active form of vitamin D and the vitamin D receptor (VDR) affects the transcription of thousands of genes by binding to repeated sequences present in their promoter region, named vitamin D-responsive elements (VDREs). Non-transcriptional effects, on the other hand, occur quickly and are unaffected by inhibitors of transcription and protein synthesis. Recently, calcifediol, the immediate precursor metabolite of calcitriol, has also been shown to bind to the VDR with weaker affinity than calcitriol, thus exerting gene-regulatory properties. Moreover, calcifediol may also trigger rapid non-genomic responses through its interaction with specific membrane vitamin D receptors. Membrane-associated VDR (mVDR) and protein disulfide isomerase family A member 3 (Pdia3) are the best-studied candidates for mediating these rapid responses to vitamin D metabolites. This paper provides an overview of the calcifediol-related mechanisms of action, which may help to better understand the vitamin D endocrine system and to identify new therapeutic targets that could be important for treating diseases closely associated with vitamin D deficiency.

Vitamin D and Chronic Kidney Disease Association with Mineral and Bone Disorder: An Appraisal of Tangled Guidelines

Chronic kidney disease (CKD) is a highly prevalent condition worldwide in which the kidneys lose many abilities, such as the regulation of vitamin D (VD) metabolism. Moreover, people with CKD are at a higher risk of multifactorial VD deficiency, which has been extensively associated with poor outcomes, including bone disease, cardiovascular disease, and higher mortality. Evidence is abundant in terms of the association of negative outcomes with low levels of VD, but recent studies have lowered previous high expectations regarding the beneficial effects of VD supplementation in the general population. Although controversies still exist, the diagnosis and treatment of VD have not been excluded from nephrology guidelines, and much data still supports VD supplementation in CKD patients. In this narrative review, we briefly summarize evolving controversies and useful clinical approaches, underscoring that the adverse effects of VD derivatives must be balanced against the need for effective prevention of progressive and severe secondary hyperparathyroidism. Guidelines vary, but there seems to be general agreement that VD deficiency should be avoided in CKD patients, and it is likely that one should not wait until severe SHPT is present before cautiously starting VD derivatives. Furthermore, it is emphasized that the goal should not be the complete normalization of parathyroid hormone (PTH) levels. New developments may help us to better define optimal VD and PTH at different CKD stages, but large trials are still needed to confirm that VD and precise control of these and other CKD-MBD biomarkers are unequivocally related to improved hard outcomes in this population.

Assessment of the Association of Vitamin D and the Risk of Tuberculosis among End-Stage Kidney Disease Population

We investigated the role of vitamin D in the risk of tuberculosis (TB) among patients with end-stage kidney disease (ESKD). The retrospective cohort was conducted with data of 20,985 patients with kidney disease and 20,985 controls without kidney disease (1:1 matching on age of cohort entry and sex) in the duration of 1997−2010 from the Taiwan National Health insurance database. Then, by a case−cohort study, among 20,985 kidney disease, 3194 ESKD patients were identified with matched 3194 non-ESKD patients. Multivariate analyses revealed a significant association between kidney disease and tuberculosis (adjusted incidence rate ratio (IRR) 1.57 (1.33−1.86)), and the risk increased after 3 years of follow-up the (adjusted IRR 3.79 (2.55−5.62)), but after more years of follow-up no significance was observed. We also found that ESKD increases the risk of tuberculosis (adjusted IRR 3.67 (2.27−5.93)). However, vitamin D usage was not related with the tuberculosis risk in ESKD patients (p > 0.1783). Our study showed increased risk of tuberculosis in kidney disease and ESKD patients, and vitamin D was not beneficial in ESKD.

C3-Epimer of 25-Hydroxyvitamin D3 as a Superior Marker for Predicting the Severity of Chronic Kidney Disease in Rheumatoid Arthritis Patients

Objective. 25-hydroxyvitamin D3 (25[OH]D3) is involved in oxidative stress regulation by upregulating the expression of antioxidant genes except for mineral homeostasis physiological role. C3-epimer of 25(OH)D3 (C3-epi-25[OH]D3) is a form of vitamin D metabolite with low bioaffinity in vivo, but little is known about the relationship between C3-epi-25(OH)D3 and diseases. This study was aimed at investigating the relationship between C3-epi-25(OH)D3 and the severity of chronic kidney disease (CKD) in patients with rheumatoid arthritis (RA). Method. A total of 318 RA inpatients were enrolled and divided into mild ( $n=247$ ), moderate ( $n=46$ ), and severe ( $n=25$ ) CKD groups according to the CKD prognosis criterion of the Kidney Disease Improving Global Outcomes guidelines. Serum levels of 25(OH)D2, 25(OH)D3, C3-epi-25(OH)D3, and free 25(OH)D (F25[OH]D) were measured, and the value of 25(OH)D was calculated. The relationship and changing trend of the indexes based on CKD severity were analyzed. Results. The serum levels of 25(OH)D, 25(OH)D3, and F25(OH)D showed a decreasing trend ( $z=-2.781–-3.996$ , $P<0.01$ ) in RA patients with CKD progression from mild to severe, while C3-epi-25(OH)D3 showed an increasing trend ( $z=6.741$ , $P<0.001$ ) and 25(OH)D2 showed no significant difference among the groups ( $z=0.976$ , $P=0.329$ ). Only levels of C3-epi-25(OH)D3 presented significant differences between adjacent CKD severity groups in RA patients (mild to moderate: $z=3.963$ , $Padj<0.001$ ; moderate to severe: $z=3.269$ , $Padj=0.002$ ). Multiple logistic regression analysis showed that 25(OH)D3 and C3-epi-25(OH)D3 were significant predictors for CKD progression in RA patients, and C3-epi-25(OH)D3 had a better predictive advantage (moderate vs. mild: $\text{OR}=4.79$ , $P<0.001$ ; severe vs. mild: $\text{OR}=17.85$ , $P<0.001$ ). Conclusions. To the best of our knowledge, this is the first study to reveal that C3-epi-25(OH)D3 is a dominant predictor of CKD severity in RA patients. Further studies are needed to explore the relationship between C3-epi-25(OH)D3 and other diseases.

Study on the Effect of Combination of Prednisone and Vitamin D in the Treatment of Primary Nephrotic Syndrome in Children

Objective

To study the effect of prednisone combined with vitamin D in the treatment of primary nephrotic syndrome in children.

Method

73 cases of primary nephrotic syndrome admitted to the nephrology department of our hospital were randomly selected and retrospectively analyzed. 36 cases were treated with prednisone as the control group, and 37 cases were treated with prednisone combined with vitamin D as the observation group. The efficacy was compared after 3 months of continuous treatment.

Result

After 3 months of treatment, the blood calcium of the observation group was higher than that of the control group, PTH was lower than that of the control group, and 25-(OH)2D3 and 1,25-(OH)2D3 were higher than those of the control group (P < 0.05). After 1, 2, and 3 months of treatment in the observation group, Scr and 24-h urine protein quantification were lower than those in the control group and eGFR was higher than that in the control group (P < 0.05). CD4+ and CD4+/CD8+ were lower in the observation group than in the control group after 3 months of treatment (P < 0.05). The serum sTfR and TGF-β1 levels were lower in the observation group than in the control group after 3 months of treatment (P < 0.05). The total effective rate of the observation group was 83.78% after 3 months of combined treatment with prednisone and vitamin D, which was significantly higher than the total effective rate of the control group of 61.11% (P < 0.05). The incidence of nausea and vomiting, heartburn, headache, dry cough, hypercalcemia, and constipation during treatment in the observation group was not statistically different from that in the control group (P > 0.05).

Conclusion

Combined treatment of primary nephrotic syndrome in children with prednisone and vitamin D can more significantly improve the level of clinical indicators, improve renal function and immune function, and obtain more satisfactory efficacy, without significantly affecting the safety of treatment.

Calcifediol supplementation in adults on hemodialysis: a randomized controlled trial

BACKGROUND

Vitamin D deficiency is associated with increased risks of mortality in people with chronic kidney disease. The benefits and harm of vitamin D supplementation on cardiovascular outcomes and mortality are unknown. We aimed to assess the effectiveness of calcifediol in reducing mortality in patients with vitamin D insufficiency on hemodialysis compared to no additional therapy.

METHODS

A phase III, multicenter, randomized, open-label trial was conducted including 284 adults with vitamin D insufficiency undergoing hemodialysis who were randomly assigned to receive oral calcifediol or standard care for 24 months.

RESULTS

Two hundred eighty-four participants were enrolled (143 assigned to the calcifediol group and 141 to the no additional therapy group). The primary outcome (mortality) occurred in 34 and 31 participants in the calcifediol and control group, respectively [hazard ratio (HR) 1.03; 95% confidence interval (CI) 0.63-1.67]. Calcifediol had no detectable effects on cardiovascular death (HR 1.06; 95% CI 0.41-2.74), non-cardiovascular death (HR 1.13; 95% CI 0.62-2.04), nonfatal myocardial infarction (HR 0.20; 95% CI 0.02-1.67) or nonfatal stroke (HR could not be estimated). The incidence of hypercalcemia and hyperphosphatemia was similar between groups. None of the participants underwent parathyroidectomy.

CONCLUSIONS

In adults treated with hemodialysis and who had vitamin D insufficiency, calcifediol supplementation for 24 months had inconclusive effects on mortality and cardiovascular outcomes.

TRIAL REGISTRATION NUMBER

NCT01457001.

Evaluation of vitamin D storage in patients with chronic kidney disease: Detection of serum vitamin D metabolites using high performance liquid chromatography-tandem mass spectrometry

BACKGROUND

Vitamin D (VitD) deficiency is extremely common in chronic kidney disease (CKD). However, the current clinical testing of vitamin D is based on the recommended serum 25-hydroxyvitamin D [25(OH)D]. The levels of VitD components in CKD patients are rarely reported. In this study, we tested various VitD components, and used different methods to evaluate the VitD status of CKD patients in vivo.

METHODS

Totally 173 CKD patients and 111 control individuals were enrolled. Serum levels of 25(OH)D₂, 25(OH)D₃, C₃-epimers (C₃-epi) and free 25(OH)D [f-25(OH)D] were measured. The 25(OH)D₂/25(OH)D₃ ratio, C₃-epi/25(OH)D₃ ratio, total 25(OH)D [t-25(OH)D], and bioavailable vitamin D (BAVD) were calculated, respectively.

RESULTS

The ratios of 25(OH)D₂/25(OH)D₃, C₃-epi/25(OH)D₃, and the level of C₃-epi in CKD patients were significantly higher than those in the control group (all P < 0.05). The levels of t-25(OH)D, 25(OH)D₃, C₃-epi, f-25(OH)D and BAVD in patients with CKD stage 5 were significantly lower than those in stages 2, 3, and 4 (all P < 0.05). The calculated VitD storage according to Method 3 [25(OH)D₂/3 + 25(OH)D₃] was only 32.95 %, which was lower than the results of 53.76 % by Method 1 [25(OH)D₂+ 25(OH)D₃+C₃-epi] and 48.56 % by Method 2 [25(OH)D₂/3 + 25(OH)D₃+C₃-epi]. In addition, the VitD results calculated by three methods were positively correlated with f-25(OH)D and BAVD, while C₃-epi levels were also positively correlated with f-25(OH)D and BAVD.

CONCLUSION

Serum levels of t-25(OH)D, 25(OH)D₃, C₃-epi, f-25(OH)D and BAVD in CKD patients gradually decrease with the progression of CKD stages. Though the results of VitD storage in CKD patients evaluated by different methods are different, simultaneous detection of 25(OH)D₂, 25(OH)D₃, C₃-epi and f-25(OH)D levels and fully estimation of their respective biological activities could accurately evaluate the VitD storage in vivo.

Efficacy of Weekly Split versus Single Doses of Ergocalciferol on Serum 25-Hydroxyvitamin D among Patients on Continuous Ambulatory Peritoneal Dialysis: A Randomized Controlled Trial

Background

Vitamin D deficiency is a common problem among patients on continuous ambulatory peritoneal dialysis (CAPD). Vitamin D supplementation leads to reduced serum parathyroid hormone levels and improved cardiovascular markers. Different doses and time intervals of oral vitamin D supplementation may differ in each patient on dialysis. The study aimed to evaluate the efficacy of weekly split and single dose of ergocalciferol at 60,000 IU on serum 25-hydroxyvitamin D (25(OH)D) among patients on CAPD.

Methods

A randomized study was conducted among patients on CAPD with vitamin D deficiency or insufficiency (25(OH)D < 30 ng/mL). Patients were randomly assigned to two groups: the split dose group was given ergocalciferol 20,000 IU three times weekly and the single dose group was given ergocalciferol 60,000 IU once weekly for 8 weeks. Main outcomes measured serum 25(OH)D concentrations, serum calcium, serum phosphate, and intact parathyroid levels at 8 weeks after being enrolled.

Results

Of 128 screened patients, 50 met the criteria for eligibility and were randomized. At 8 weeks after treatment, mean serum 25(OH)D concentrations significantly increased from baseline 22.7 ± 5.9 to 29.5 ± 9.5 ng/mL (P=0.004) in the split dose group and 22.9 ± 5.3 to 31.2 ± 12.3 ng/mL (P=0.003) in the single dose group. No significant change was found in increase of serum 25(OH)D between the two groups (P=0.561). At the end of study, a similar proportion of patients in both groups reached the desirable serum concentration of 25(OH)D ≥ 30 ng/mL (60% in the single group vs. 40% in the split group, P=0.258). No significant cases of hypercalcemia, hyperphosphatemia, or serious adverse events occurred during the study.

Conclusion

Weekly single and split doses of ergocalciferol 60,000 IU achieved similar effects on serum 25(OH)D levels among patients on CAPD with vitamin D insufficiency or deficiency, suggesting that weekly single dose would be prescribed for adequate vitamin D repletion. This trial is registered with TCTR20200821005.

Vitamin K and D Supplementation and Bone Health in Chronic Kidney Disease-Apart or Together?

Vitamin K (VK) and vitamin D (VD) deficiency/insufficiency is a common feature of chronic kidney disease (CKD), leading to impaired bone quality and a higher risk of fractures. CKD patients, with disturbances in VK and VD metabolism, do not have sufficient levels of these vitamins for maintaining normal bone formation and mineralization. So far, there has been no consensus on what serum VK and VD levels can be considered sufficient in this particular population. Moreover, there are no clear guidelines how supplementation of these vitamins should be carried out in the course of CKD. Based on the existing results of preclinical studies and clinical evidence, this review intends to discuss the effect of VK and VD on bone remodeling in CKD. Although the mechanisms of action and the effects of these vitamins on bone are distinct, we try to find evidence for synergy between them in relation to bone metabolism, to answer the question of whether combined supplementation of VK and VD will be more beneficial for bone health in the CKD population than administering each of these vitamins separately.

Are Nutraceuticals Beneficial in Chronic Kidney Disease?

Chronic kidney disease (CKD) is a worldwide health problem in which prevalence is constantly rising. The pathophysiology of CKD is complicated and has not been fully resolved. However, elevated oxidative stress is considered to play a vital role in the development of this disease. CKD is also thought to be an inflammatory disorder in which uremic toxins participate in the development of the inflammatory milieu. A healthy, balanced diet supports the maintenance of a good health status as it helps to reduce the risk of the development of chronic diseases, including chronic kidney disease, diabetes mellitus, and hypertension. Numerous studies have demonstrated that functional molecules and nutrients, including fatty acids and fiber as well as nutraceuticals such as curcumin, steviol glycosides, and resveratrol not only exert beneficial effects on pro-inflammatory and anti-inflammatory pathways but also on gut mucosa. Nutraceuticals have attracted great interest recently due to their potential favorable physiological effects on the human body and their safety. This review presents some nutraceuticals in which consumption could exert a beneficial impact on the development and progression of renal disease as well cardiovascular disease.

Analysis of vitamin D level among asymptomatic and critically ill COVID-19 patients and its correlation with inflammatory markers

COVID-19 is characterized by marked variability in clinical severity. Vitamin D had recently been reviewed as one of the factors that may affect the severity in COVID-19. The objective of current study is to analyze the vitamin D level in COVID-19 patients and its impact on the disease severity. After approval from Ethics Committee, M.L.B Medical College the current study was undertaken as continuous prospective observational study of 6 weeks. Participants were COVID-19 patients of age group 30–60 years admitted during the study period of 6 weeks. Study included either asymptomatic COVID-19 patients (Group A) or severely ill patients requiring ICU admission (Group B). Serum concentration of 25 (OH)D, were measured along with serum IL-6; TNFα and serum ferritin. Standard statistical analysis was performed to analyze the differences. Current Study enrolled 154 patients, 91 in Group A and 63 patients in Group B. The mean level of vitamin D (in ng/mL) was 27.89 ± 6.21 in Group A and 14.35 ± 5.79 in Group B, the difference was highly significant. The prevalence of vitamin D deficiency was 32.96% and 96.82% respectively in Group A and Group B. Out of total 154 patients, 90 patients were found to be deficient in vitamin D (Group A: 29; Group B: 61). Serum level of inflammatory markers was found to be higher in vitamin D deficient COVID-19 patients viz. IL-6 level (in pg/mL) 19.34 ± 6.17 vs 12.18 ± 4.29; Serum ferritin 319.17 ± 38.21 ng/mL vs 186.83 ± 20.18 ng/mL; TNFα level (in pg/mL) 13.26 ± 5.64 vs 11.87 ± 3.15. The fatality rate was high in vitamin D deficient (21% vs 3.1%). Vitamin D level is markedly low in severe COVID-19 patients. Inflammatory response is high in vitamin D deficient COVID-19 patients. This all translates into increased mortality in vitamin D deficient COVID-19 patients. As per the flexible approach in the current COVID-19 pandemic authors recommend mass administration of vitamin D supplements to population at risk for COVID-19.

Correct use of non-indexed eGFR for drug dosing and renal drug-related problems at hospital admission

Purpose

Two to seven percent of the German adult population has a renal impairment (RI) with an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m². This often remains unrecognized and adjustment of drug therapy is lacking. To determine renal function in clinical routine, the CKD-EPI equation is used to calculate an indexed eGFR (ml/min/1.73m²). For drug dosing, it has to be individualized to a non-indexed eGFR (ml/min) by the patient’s body surface area. Here, we investigated the number of patients admitted to urological wards of a teaching hospital with RI between July and December 2016. Additionally, we correctly used the eGFR_non-indexed for drug and dosage adjustments and to analyse the use of renal risk drugs (RRD) and renal drug-related problems (rDRP).

Methods

In a retrospective observational study, urological patients with pharmacist-led medication reconciliation at hospital admission and eGFR_indexed (CKD-EPI) of 15–59 ml/min/1.73m² were identified. Indexed eGFR (ml/min/1.73m²) was recalculated with body surface area to non-indexed eGFR (ml/min) for correct drug dosing. Medication at admission was reviewed for RRD and based on the eGFR_non-indexed for rDRP, e.g. inappropriate dose or contraindication.

Results

Of 1320 screened patients, 270 (20.5%) presented with an eGFR_indexed of 15–59 ml/min/1.73m². After readjustment, 203 (15.4%) patients had an eGFR_non-indexed of 15–59 ml/min. Of these, 190 (93.6%) used ≥ 1 drugs at admission with 660 of 1209 (54.7%) drugs classified as RRD. At least one rDRP was identified in 115 (60.5%) patients concerning 264 (21.8%) drugs.

Conclusion

Renal impairment is a common risk factor for medication safety in urologic patients admitted to a hospital. Considerable shifts were seen in eGFR-categories when correctly calculating eGFR_non-indexed for drug dosing purposes. The fact that more than half of the study patients showed rDRP at hospital admission underlines the need to consider this risk factor appropriately.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02953-6) contains supplementary material, which is available to authorized users.

Role of vitamin D in oxidative stress modulation in end-stage renal disease patients: A double-blind randomized clinical trial

INTRODUCTION

Oxidative stress is considered as important actor in uremia-associated morbidity and mortality in hemodialysis (HD) patients. We aimed to evaluate the role of vitamin D supplementation on oxidative stress parameters in this group.

METHODS

This double-blind randomized clinical trial was conducted on HD patients who were randomly allocated into intervention (n = 40) or control groups (n = 38) for 10 weeks. Blood samples were taken before and at the end of the trial to measure serum 25-hydroxyvitamin D (25(OH)D), malondialdehyde (MDA), glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD). Data were analyzed using SPSS, and P value <0.05 was considered to be statistically significant.

FINDINGS

Out of the 78 patients with a mean age of 44.7 ± 13.0 years, 55.1% were men. At the commencement of the study, there was no difference with respect to serum 25(OH)D levels in our groups (P = 0.575), but during the study it was significantly elevated in the intervention group (18.1 ± 9.1 vs. 31.7 ± 12.9, P < 0.0001). Serum antioxidative enzymes activity (GPx, CAT, and SOD) had significantly increased after vitamin D supplementation in the intervention group (P < 0.05). Furthermore, MDA levels was significantly reduced only in the intervention group (31.7 ± 18.0 vs. 24.7 ± 7.7, P = 0.018).

DISCUSSION

Regular consumption of vitamin D can increase the GPx, CAT, SOD, and reduce the MDA plasma levels in HD patients. Since no adverse effects of vitamin D supplementation was reported by the patients; hence, it can be prescribed for HD patients.

Cholecalciferol or Calcifediol in the Management of Vitamin D Deficiency

Vitamin D deficiency is a global health problem due to its high prevalence and its negative consequences on musculoskeletal and extra-skeletal health. In our comparative review of the two exogenous vitamin D supplementation options most used in our care setting, we found that cholecalciferol has more scientific evidence with positive results than calcifediol in musculoskeletal diseases and that it is the form of vitamin D of choice in the most accepted and internationally recognized clinical guidelines on the management of osteoporosis. Cholecalciferol, unlike calcifediol, guarantees an exact dosage in IU (International Units) of vitamin D and has pharmacokinetic properties that allow either daily or even weekly, fortnightly, or monthly administration in its equivalent doses, which can facilitate adherence to treatment. Regardless of the pattern of administration, cholecalciferol may be more likely to achieve serum levels of 25(OH)D (25-hydroxy-vitamin D) of 30-50 ng/mL, an interval considered optimal for maximum benefit at the lowest risk. In summary, the form of vitamin D of choice for exogenous supplementation should be cholecalciferol, with calcifediol reserved for patients with liver failure or severe intestinal malabsorption syndromes.

Nutritional vitamin D in CKD: Should we measure? Should we treat?

Vitamin Ddeficiency is frequently present in patients affected by chronic kidney disease (CKD). Experimental studies demonstrated that Vitamin D may play a role in the pathophysiology of diseases beyond mineral bone disorders in CKD (CKD-MBD). Unfortunately, the lack of large and interventional studies focused on the so called "non-classic" effects of 25(OH) Vitamin D supplementation in CKD patients, doesn't permit to conclude definitely about the beneficial effects of this supplementation in clinical practice. In conclusion, treatment of nutritional vitamin D deficiency in CKD may play a central role in both bone homeostasis and cardiovascular outcomes, but there is not clear evidence to support one formulation of nutritional vitamin D over another in CKD.