A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial of High-Dose, Short-Term Vitamin D Administration in the Prevention of Acute Kidney Injury after Cardiac Surgery

Effect of preoperative vitamin D on postoperative atrial fibrillation incidence after coronary artery bypass grafting

BACKGROUND

Post-operative atrial fibrillation (POAF) is associated with adverse long-term cardiovascular events.

OBJECTIVES

This study investigated the effects of a high-dose vitamin D administered preoperatively on the postoperative atrial fibrillation (POAF) incidence in patients with vitamin D deficiency following coronary artery bypass grafting (CABG) surgery.

METHODS

This randomized controlled clinical trial was conducted on 246 CABG patients with vitamin D deficiency. All patients were randomly divided into intervention and control groups including 123 cases for each group. In the intervention group, from 3 days before surgery, they received a daily dose of 150,000 units of vitamin D orally (50,000 units of Vit D tablet three times a day) and the patients in the control group received placebo tablets before surgery. All patients in the intervention group were assessed continuously for the occurrence of POAF during the recovery period.

RESULTS

In terms of gender, age, and BMI there were no significant differences between intervention and control groups. Our findings showed that the use of vitamin D supplements did not cause a significant change in the duration of intubation and hospitalization. The ratio of POAF following CABG surgery in the control and treatment groups was 26% and 11.4%, respectively (odds ratio = 0.36; 95% CI = 0.18-0.72; P = 0.003).

CONCLUSIONS

Our findings revealed that high-dose vitamin D supplementation before CABG surgery significantly reduced the incidence of POAF. Further multicenter randomized trials with larger sample sizes are certainly warranted to confirm our results.

Vitamin D and cardiovascular diseases

Vitamin D has an established role in calcium homeostasis but its deficiency is emerging also as a new risk factor for cardiovascular disease (CVD). In particular, several epidemiological and clinical studies have reported a close association between low vitamin D levels and several cardiovascular risk factors and major CVDs, such as coronary artery disease, heart failure, and cardiac arrhythmias. In all these clinical settings, vitamin D deficiency seems to predispose to increased morbidity, mortality, and recurrent cardiovascular events. Despite this growing evidence, interventional trials with supplementation of vitamin D in patients at risk of or with established CVD are still controversial. In this chapter, we summarize the currently available evidence on the links between vitamin D deficiency and major cardiovascular risk factors and CVD, in terms of both clinical relevance and potential therapeutic implications.

Role of vitamin D supplementation in modifying outcomes after surgery: a systematic review of randomised controlled trials

BACKGROUND

There is increasing evidence to suggest vitamin D plays a role in immune and vascular function; hence, it may be of biological and clinical relevance for patients undergoing major surgery. With a greater number of randomised studies being conducted evaluating the impact of vitamin D supplementation on surgical patients, it is an opportune time to conduct further analysis of the impact of vitamin D on surgical outcomes.

METHODS

MEDLINE, EMBASE and the Cochrane Trials Register were interrogated up to December 2023 to identify randomised controlled trials of vitamin D supplementation in surgery. The risk of bias in the included studies was assessed using the Cochrane Risk of Bias tool. A narrative synthesis was conducted for all studies. The primary outcome assessed was overall postoperative survival.

RESULTS

We screened 4883 unique studies, assessed 236 full-text articles and included 14 articles in the qualitative synthesis, comprising 1982 patients. The included studies were highly heterogeneous with respect to patient conditions, ranging from open heart surgery to cancer operations to orthopaedic conditions, and also with respect to the timing and equivalent daily dose of vitamin D supplementation (range: 0.5-7500 mcg; 20-300 000 IU). No studies reported significant differences in overall survival or postoperative mortality with vitamin D supplementation. There was also no clear evidence of benefit with respect to overall or intensive care unit length of stay.

DISCUSSION

Numerous studies have reported the benefits of vitamin D supplementation in different surgical settings without any consistency. However, this systematic review found no clear evidence of benefit, which warrants the supposition that a single biological effect of vitamin D supplementation does not exist. The observed improvement in outcomes in low vitamin D groups has not been convincingly proven beyond chance findings.

TRIAL REGISTRATION NUMBER

CRD42021232067.

Associations between Serum 25-hydroxyvitamin D, Sun Exposure Time, Dietary Vitamin D Intake, and New-Onset Acute Kidney Injury among 413,169 UK Adults

BACKGROUND

The prospective associations of serum 25(OH)D, sun exposure time, and dietary vitamin D with risk of acute kidney injury (AKI) are unclear.

OBJECTIVES

We aimed to evaluate the relations of serum 25(OH)D, sun exposure time, and dietary vitamin D intake with new-onset AKI and examine whether genetic susceptibility modified such associations.

METHODS

A total of 413,169 participants (mean age was 56.4 y, 47.2% were male) from UK Biobank without prior AKI were included. Sun exposure time was expressed as time spent outdoors. Genetic risk scores were calculated by 263 single nucleotide polymorphisms, which showed significant associations with the estimated glomerular filtration rate. The primary outcome was new-onset AKI. Cox proportional hazards models were used to estimate the HRs and (95% CIs).

RESULTS

During a median follow-up duration of 12 y, 16,938 (4.1%) participates developed new-onset AKI. Compared with those with serum 25(OH)D <25 nmol/L, significantly lower risks of new-onset AKI were found between participants with 25(OH)D 25 to <50 nmol/L (adjusted HR: 0.76; 95% CI: 0.73, 0.80), and ≥50 nmol/L (adjusted HR: 0.69; 95% CI: 0.65, 0.72). Moreover, in summer, participants who spent ≥4 h outdoors per day (tertile 3) had a significantly lower risk of new-onset AKI (adjusted HR: 0.90; 95% CI: 0.86, 0.95) than those who spent <2 h outdoors per day (tertile 1). Similar results were found for time spent outdoors in winter. In addition, those in quintile 5 of dietary vitamin D intake showed a lower risk of new-onset AKI (≥4.2 μg/d, adjusted HR: 0.90; 95% CI: 0.82, 0.98) than those in quintile 1 (<1.0 μg/d). Genetic risks of kidney diseases did not significantly modify all the 3 above associations (all P-interactions >0.05).

CONCLUSIONS

Serum 25(OH)D concentrations, time spent outdoors, and dietary vitamin D intake were all inversely associated with new-onset AKI, independent of genetic risks for kidney diseases.

Vitamin D Supplementation Has No Impact on Cardiorespiratory Fitness, but Improves Inflammatory Status in Vitamin D Deficient Young Men Engaged in Resistance Training

Data on the effect of vitamin D (Vit-D) supplementation on cardiorespiratory fitness (VO2max) are conflicting. A possible source of discrepancies in the literature is the heterogeneity in baseline Vit-D status among participants in previous studies. The main objectives of the present study were to assess the impact of Vit-D supplementation on VO2max and inflammatory status in Vit-D deficient young healthy men. Participants (n = 39, baseline serum Vit-D level < 50 nmol/L) were quasi-randomly assigned to one of the two groups, which, in a double-blind manner, supplemented their diet daily with either Vit-D (8000 IU; VD) or placebo (PLC) and concomitantly performed a 12-week supervised resistance training program. During the 12-week intervention, serum Vit-D concentrations increased 3.9-fold (p < 0.001) in the VD group while no changes occurred in the PLC group. Baseline VO2max did not differ in the two groups and remained unchanged during the intervention. Serum interleukin-10/tumour necrosis factor alpha ratio increased significantly (30%, p = 0.007; effect size 0.399) in VD but not in PLC group. In conclusion, 12-week Vit-D supplementation increases serum 25(OH)D levels and improves inflammatory status, but has no impact on VO2max in Vit-D deficient young men engaged in resistance training.

Strategies for post–cardiac surgery acute kidney injury prevention: A network meta-analysis of randomized controlled trials

Objects

Cardiac surgery is associated with acute kidney injury (AKI). However, the effects of various pharmacological and non-pharmacological strategies for AKI prevention have not been thoroughly investigated, and their effectiveness in preventing AKI-related adverse outcomes has not been systematically evaluated.

Methods

Studies from PubMed, Embase, and Medline and registered trials from published through December 2021 that evaluated strategies for preventing post–cardiac surgery AKI were identified. The effectiveness of these strategies was assessed through a network meta-analysis (NMA). The secondary outcomes were prevention of dialysis-requiring AKI, mortality, intensive care unit (ICU) length of stay (LOS), and hospital LOS. The interventions were ranked using the P-score method. Confidence in the results of the NMA was assessed using the Confidence in NMA (CINeMA) framework.

Results

A total of 161 trials (involving 46,619 participants) and 53 strategies were identified. Eight pharmacological strategies {natriuretic peptides [odds ratio (OR): 0.30, 95% confidence interval (CI): 0.19–0.47], nitroprusside [OR: 0.29, 95% CI: 0.12–0.68], fenoldopam [OR: 0.36, 95% CI: 0.17–0.76], tolvaptan [OR: 0.35, 95% CI: 0.14–0.90], N-acetyl cysteine with carvedilol [OR: 0.37, 95% CI: 0.16–0.85], dexmedetomidine [OR: 0.49, 95% CI: 0.32–0.76;], levosimendan [OR: 0.56, 95% CI: 0.37–0.84], and erythropoietin [OR: 0.62, 95% CI: 0.41–0.94]} and one non-pharmacological intervention (remote ischemic preconditioning, OR: 0.76, 95% CI: 0.63–0.92) were associated with a lower incidence of post–cardiac surgery AKI with moderate to low confidence. Among these nine strategies, five (fenoldopam, erythropoietin, natriuretic peptides, levosimendan, and remote ischemic preconditioning) were associated with a shorter ICU LOS, and two (natriuretic peptides [OR: 0.30, 95% CI: 0.15–0.60] and levosimendan [OR: 0.68, 95% CI: 0.49–0.95]) were associated with a lower incidence of dialysis-requiring AKI. Natriuretic peptides were also associated with a lower risk of mortality (OR: 0.50, 95% CI: 0.29–0.86). The results of a sensitivity analysis support the robustness and effectiveness of natriuretic peptides and dexmedetomidine.

Conclusion

Nine potentially effective strategies were identified. Natriuretic peptide therapy was the most effective pharmacological strategy, and remote ischemic preconditioning was the only effective non-pharmacological strategy. Preventive strategies might also help prevent AKI-related adverse outcomes. Additional studies are required to explore the optimal dosages and protocols for potentially effective AKI prevention strategies.

Effect of Vitamin D Supplementation on Postoperative Outcomes in Cardiac Surgery Patients: A Systematic Review

Background Vitamin D deficiency is a very common occurrence in cardiac patients. It has been proved that cardiac surgery and cardiopulmonary bypass accelerate the deficiency further. The postoperative outcomes of patients deteriorate in the presence of vitamin D deficiency. Perioperative supplementation of vitamin D is the only solution to the problem. Hence, the present systematic review was conducted to derive the efficacy and safety of vitamin D supplementation on postoperative outcomes in cardiac surgery patients.

Method Publications over duration of last 10 years was searched from different database and web sites. The data from full-text research articles were analyzed for the effect on different postoperative outcomes and side effects.

Result Eight randomized control trials were retrieved on the effect of perioperative vitamin D supplementation in cardiac surgery patients and their postoperative outcomes. Six articles (75%) were found to be in favor of improvement in postoperative outcome. Two articles (25%) did not find any difference of outcome between the control and treatment group. All the studies observed the restoration of vitamin D to normal and no adverse effects from supplementation.

Conclusion Perioperative vitamin D supplementation improves the postoperative outcomes after cardiac surgery. It is effective and safe to supplement vitamin D in cardiac surgery patients.