Significant perturbation of vitamin D-parathyroid-calcium axis and adverse clinical outcomes in critically ill patients

The Immunomodulatory Activity of High Doses of Vitamin D in Critical Care Patients with Severe SARS-CoV-2 Pneumonia-A Randomized Controlled Trial

Vitamin D receptor [VDR] expression promotes LL37 expression, possibly contributing to host defense. The hypothesis was that an increase in 25 hydroxyvitamin D [25vitD] could lead to enhanced VDR expression and increased LL-37 production, thereby contributing to improved prognosis in critically ill patients. Methods: A nonblinded, randomized controlled trial was conducted. A total of 207 patients admitted to ICU with severe SARS-CoV-2 pneumonia were included and received different doses of cholecalciferol (500 MU, 3 MU/day, no cholecalciferol) during their ICU and hospital stay. 25vitD levels as well as LL37 and monocytes' VDR gene expression were evaluated on admission and after. Clinical evolution, ICU mortality, hospital mortality, and 60-day mortality were evaluated. Results: The median age was 57.7 years and the majority of patients were Caucasian [87.4%] and male [70.5%]. There was a significant difference in 25vitD levels between groups on the third [p = 0.002] and seventh [p < 0.001] days. Patients supplemented with 500 MU of cholecalciferol had a very significant increase in monocytes' VDR gene expression and showed a better clinical evolution in the ICU, with a significant correlation to evolution factors. Higher LL37 on admission had a significant negative association with hospital and ICU mortality, lost after adjustment for comorbidities to a nearly significant association with ICU, hospital, and 60-day mortality. Conclusion: Supplementation with higher doses of cholecalciferol may contribute to a significant increase in 25vitD levels but not in LL37 levels. Higher LL37 levels on admission may be related to a decrease in ICU, hospital, and 60-day mortality. VDR gene expression in monocytes is much higher in patients supplemented with higher doses of cholecalciferol.

25-hydroxyvitamin D and parathyroid hormone in new onset sepsis: A prospective study in critically ill patients

Hypovitaminosis D is highly prevalent in critically ill patients, and it has been suggested to be a risk factor for infections, sepsis and higher mortality. We sought to investigate whether serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) in critically ill patients with new onset sepsis are associated with severity and outcome. We prospectively included 50 consecutive critically ill adult cases with new onset sepsis and 50 healthy controls matched for age and sex. PTH and 25(OH)D were determined in serum via electrochemiluminescence immunoassays at inclusion in the study in all cases and controls, and one week after sepsis onset in cases. Patients had reduced 25(OH)D compared to controls at sepsis onset (7.9 ± 3 vs 24.6 ± 6.7 ng/mL, p < 0.001), whilst PTH was similar (median (range): 34.5 (5.7-218.5) vs 44.2 (14.2-98.1) pg/mL, p = 0.35). In patients, 25(OH)D upon enrollment and one week after did not differ significantly (7.9 ± 3 vs 7 ± 4.3 ng/mL, p = 0.19). All patients presented with hypovitaminosis D (25(OH)D < 20 ng/mL), while 40 patients (80 %) had vitamin D deficiency (25(OH)D < 12 ng/mL) at sepsis onset, including all ten (20 %) nonsurvivors, who died within 28 days from sepsis onset. Patients with sepsis (N = 28) and septic shock (N = 22) as well as survivors (N = 40) and nonsurvivors (N = 10) had similar 25(OH)D at enrollment (p > 0.05). 25(OH)D was positively correlated with ionized calcium (r = 0.46, p < 0.001) and negatively with PTH (p < 0.05), while inflammatory biomarkers or the severity scores exhibited no correlation with 25(OH)D. Patients with septic shock and nonsurvivors had lower PTH than patients with sepsis and survivors respectively (42.2 ± 42.9 vs 73.4 ± 61.9 pg/mL, p = 0.04, and 18.3 ± 10.7 vs 69.9 ± 58.8 pg/mL, p = 0.001, respectively). C-reactive protein was negatively associated with PTH (r = -0.44, p = 0.001). In conclusion, vitamin D deficiency was present in 80 % of critically ill patients at sepsis onset, while nonsurvivors exhibited lower PTH than survivors. Additional, larger and multicenter studies are warranted to elucidate the contribution of vitamin D and PTH to the pathogenesis of sepsis and its outcomes.

Potential therapeutic implications of calcitriol administration and weight reduction on CD4 T cell dysregulation and renin angiotensin system-associated acute lung injury in septic obese mice

This study investigated the effects of weight reduction and/or calcitriol administration on regulating CD4 T cell subsets and renin-angiotensin system (RAS)-associated acute lung injury (ALI) in obese mice with sepsis. Half of the mice were fed a high-fat diet for 16 weeks, half of them had high-fat diet for 12 weeks then were transferred to a low-energy diet for 4 weeks. After feeding the respective diets, cecal ligation and puncture (CLP) were performed to induce sepsis. There were four sepsis groups: OSS group, obese mice injected with saline; OSD group, obese mice given calcitriol; WSS group, mice with weight reduction and saline; WSD group, mice with weight reduction and calcitriol. Mice were sacrificed after CLP. The findings showed that CD4 T subsets distribution did not differ among the experimental groups. Calcitriol-treated groups had higher RAS-associated AT2R, MasR, ACE2, and angiopoietin 1-7 (Ang(1-7)) levels in the lungs. Also, higher tight junction proteins were noted 12 h after CLP. At 24 h post-CLP, weight reduction and/or calcitriol treatment reduced plasma inflammatory mediator production. Calcitriol-treated groups had higher CD4/CD8, T helper (Th)1/Th2 and lower Th17/regulatory T (Treg) ratios than the groups without calcitriol. In the lungs, calcitriol-treated groups had lower AT1R levels, whereas the RAS anti-inflammatory protein levels were higher than those groups without calcitriol. Lower injury scores were also noted at this time point. These findings suggested weight reduction decreased systemic inflammation. However, calcitriol administration produced a more-balanced Th/Treg distribution, upregulated the RAS anti-inflammatory pathway, and attenuated ALI in septic obese mice.

Vitamin-D ameliorates sepsis-induced acute lung injury via augmenting miR-149-5p and downregulating ER stress

Acute lung injury is a life-threatening medical problem induced by sepsis or endotoxins and may be associated with enhanced Endoplasmic reticulum stress (ER stress). Vitamin-D (Vit-D) possesses an anti-inflammatory effect; however, this specific mechanism on acute lung injury is still unknown. Here we scrutinize the mechanism of Vit-D on Acute lung injury (ALI) models and explored the Vit-D augmented miRNA's role in regulating the ER stress pathway in ALI. Sepsis was induced by CLP, and Endotoxemia was caused by lipopolysaccharide (LPS). We found that Vit-D alleviates pulmonary edema, improves lung histoarchitecture, infiltration of neutrophils, endothelial barrier in mice, and improves ER stress markers Activating Transcription Factor 6 (ATF6) and CHOP (C/EBP Homologous Protein) expression elevated by CLP/LPS induce ALI. Vit-D decreases the nitric oxide production and ATF6 in macrophages induced by LPS. Vit-D augments miR (miR-149-5p) in LPS-induce macrophages, CLP, and LPS-induced ALI models. Vit-D enhanced miRNA-149-5p when overexpressed, inhibited ER-specific ATF6 inflammatory pathway in LPS-stimulated macrophages, and improved histoarchitecture of the lung in LPS/CLP-induced mice models. This vitro and vivo studies demonstrate that Vit-D could improve ALI induced by CLP/LPS. In this regard, miR-149-5p may play a crucial role in vitamin-D inhibiting LPS/CLP induce ALI. The mechanism might be an association of increased miR-149-5p and its regulated gene target ATF6, and downstream CHOP proteins were suppressed. Thus, these findings demonstrate that the anti-inflammatory effect of Vit-D is achieved by augmentation of miRNA-149-5p expression, which may be a key physiologic mediator in the prevention and treatment of ALI.

Positive Effects of Vitamin D Supplementation in Patients Hospitalized for COVID-19: A Randomized, Double-Blind, Placebo-Controlled Trial

Retrospective studies showed a relationship between vitamin D status and COVID-19 severity and mortality, with an inverse relation between SARS-CoV-2 positivity and circulating calcifediol levels. The objective of this pilot study was to investigate the effect of vitamin D supplementation on the length of hospital stay and clinical improvement in patients with vitamin D deficiency hospitalized with COVID-19. The study was randomized, double blind and placebo controlled. A total of 50 subjects were enrolled and received, in addition to the best available COVID therapy, either vitamin D (25,000 IU per day over 4 consecutive days, followed by 25,000 IU per week up to 6 weeks) or placebo. The length of hospital stay decreased significantly in the vitamin D group compared to the placebo group (4 days vs. 8 days; p = 0.003). At Day 7, a significantly lower percentage of patients were still hospitalized in the vitamin D group compared to the placebo group (19% vs. 54%; p = 0.0161), and none of the patients treated with vitamin D were hospitalized after 21 days compared to 14% of the patients treated with placebo. Vitamin D significantly reduced the duration of supplemental oxygen among the patients who needed it (4 days vs. 7 days in the placebo group; p = 0.012) and significantly improved the clinical recovery of the patients, as assessed by the WHO scale (p = 0.0048). In conclusion, this study demonstrated that the clinical outcome of COVID-19 patients requiring hospitalization was improved by administration of vitamin D.

Hypocalcemia in hospitalized patients with COVID-19: roles of hypovitaminosis D and functional hypoparathyroidism

INTRODUCTION

Despite the high prevalence of hypocalcemia in patients with COVID-19, very limited studies have been designed to evaluate etiologies of this disorder. This study was designed to evaluate the status of serum parameters involved in calcium metabolism in patients with COVID-19 and hypocalcemia.

MATERIALS AND METHODS

This cross-sectional study was conducted on 123 hospitalized patients with COVID-19. Serum concentrations of PTH, 25 (OH) D, magnesium, phosphate, and albumin were assessed and compared across three groups of moderate/severe hypocalcemia (serum total calcium < 8 mg/dl), mild hypocalcemia (8 mg/dl ≤ serum total calcium < 8.5 mg/dl) and normocalcemia (serum total calcium ≥ 8.5 mg/dl). Multivariate analyses were performed to evaluate the independent roles of serum parameters in hypocalcemia.

RESULTS

In total, 65.9% of the patients had hypocalcemia. Vitamin D deficiency was found in 44.4% and 37.7% of moderate/severe and mild hypocalcemia cases, respectively, compared to 7.1% in the normal serum total calcium group (P = 0.003). In multivariate analysis, vitamin D deficiency was independently associated with 6.2 times higher risk of hypocalcemia (P = 0.001). Only a minority of patients with hypocalcemia had appropriately high PTH (15.1% and 14.3% in mild and moderate/severe hypocalcemia, respectively). Serum PTH was low/low-normal in 40.0% of patients with moderate/severe low-corrected calcium group. Magnesium deficiency was not associated with hypocalcemia in univariate and multivariate analysis.

CONCLUSION

Vitamin D deficiency plays a major role in hypocalcemia among hospitalized patients with COVID-19. Inappropriately low/low-normal serum PTH may be a contributing factor in this disorder.

Hypovitaminosis D and Parathyroid Hormone Response in Critically Ill Children with Sepsis: A Case-control Study

Background: Critically ill Indian children have a higher prevalence of vitamin D deficiency. However, there is not much data available on the subgroup with sepsis. It has been reported that there is an impaired response of parathyroid hormone (PTH) to vitamin D deficiency in critically ill children and adults. Hence, we also sought to analyze the PTH response to vitamin D among the subgroup of critically ill children with sepsis.

Patients and methods: Vitamin D and PTH levels of 84 critically ill children with sepsis (cases) and 84 controls were compared between November 2018 and February 2020. Hypovitaminosis D was defined as levels <30 ng/mL.

Results: The median (IQR) of vitamin D for cases was 26 (21.30–29.95) ng/mL and that for controls 39.3 (33.65–50.2) ng/mL; p <0.001. Cases had a higher prevalence of hypovitaminosis D as compared to controls (79.7 vs 9.5%; p <0.001). Among the cases, mortality was 24.6% in the 65 children with hypovitaminosis D and 10.5% in those with sufficient vitamin D; the differences were not statistically significant (p = 0.339). There were no significant differences in the duration of pediatric intensive care unit (PICU) stay, serum calcium, PTH, and disease severity among the aforementioned groups. Out of the 65 children with hypovitaminosis D, only 9 (13.8%) were PTH responders. There were no statistically significant differences in mortality, the PICU stay, or disease severity at admission between PTH responders and nonresponders.

Conclusions: Hypovitaminosis D was more prevalent among critically ill children with sepsis compared to controls. Parathyroid gland response to hypovitaminosis D was impaired in children with sepsis.

How to cite this article: Kubsad P, Ravikiran SR, Bhat KG, Kamath N, Kulkarni V, Manjrekar PA, et al. Hypovitaminosis D and Parathyroid Hormone Response in Critically Ill Children with Sepsis: A Case-control Study. Indian J Crit Care Med 2021;25(8):923–927.

Low Circulating Vitamin D in Intensive Care Unit-Admitted COVID-19 Patients as a Predictor of Negative Outcomes

BACKGROUND

Vitamin D deficiency has been associated with an increased risk of respiratory infections.

OBJECTIVES

The study aimed to evaluate the serum 25-hydroxyvitamin D [25(OH)D] concentration in patients admitted to the intensive care unit (ICU) as a predictor of coronavirus disease 2019 (COVID-19) mortality.

METHODS

A single-center retrospective observational study was conducted. Forty adult patients (50% men) with confirmed COVID-19 who were admitted to the ICU were enrolled. The primary endpoint was mortality at day 60. Serum 25(OH)D concentration was measured on the day of admission to the ICU. We used the Mann-Whitney test, Fisher's exact test, Kaplan-Meier analysis, and receiver operator characteristic (ROC) analysis to assess serum 25(OH)D concentration as a predictor of COVID-19 mortality.

RESULTS

All 40 patients had a low median (IQR) serum 25(OH)D concentration at admission [12 (9-15) ng/mL]. The median (IQR) serum 25(OH)D concentration was greater in survivors [13.3 (10.0-17.1) ng/mL, n = 22] than in nonsurvivors [9.6 (7.9-14.2) ng/mL; n = 18], P = 0.044. The area under the ROC curve was 0.69 (95% CI: 0.52, 0.86; P = 0.044). The 60-d mortality rate of those with serum 25(OH)D concentrations ≤9.9 ng/mL (n = 14, 71%) tended to be greater than that of those with concentrations >9.9 ng/mL (n = 26, 31%) (P = 0.065), and they had a 5.6-fold higher risk of death (OR: 5.63; 95% CI: 1.35, 23.45; P = 0.018).

CONCLUSIONS

The ICU patients had a low serum 25(OH)D concentration. Serum 25(OH)D concentrations ≤9.9 ng/mL on admission can be used to predict in-hospital mortality in patients with COVID-19.This trial was registered at clinicaltrials.gov as NCT04450017.

Intravenous calcitriol administration regulates the renin-angiotensin system and attenuates acute lung injury in obese mice complicated with polymicrobial sepsis

Calcitriol, an active form of vitamin D, has immunomodulatory and anti-inflammatory properties. Vitamin D levels have inverse correlation with sepsis outcomes and obesity may aggravate the severity of the diseases. This study administered calcitriol to investigate its impact on sepsis-induced acute lung injury (ALI) in obese mice. Mice were fed a high-fat diet to induce obesity and were randomly assigned to control or sepsis groups, which were intravenously administered either saline (SS) or calcitriol (SD). Sepsis was induced by cecal ligation and puncture (CLP). Saline or calcitriol was injected 1 h after CLP via tail vein. Mice were sacrificed at either 12 or 24 h post-CLP and survival rates were observed. The results demonstrated that sepsis caused upregulation of inflammatory mediators and downregulation of renin-angiotensin system (RAS)-associated gene expressions in the lungs of obese mice. Cluster of differentiation 68 (CD68) expression and myeloperoxidase (MPO) activities also increased. Calcitriol treatment lowered expressions of blood and lung inflammatory mediators at 12 and/or 24 h after CLP. The RAS-proinflammatory-associated angiotensin type 1 receptor (AT1R) was lower while anti-inflammatory Mas receptor and AT2R expressions were higher at 12 h after CLP than those in the SS group. In addition, the SD group exhibited lower CD68 expression and MPO activity. Lower lung injury scores and higher survival rates were also noted in the SD group. The findings suggest that calcitriol treatment after sepsis induction upregulated RAS-associated anti-inflammatory pathway and decreased immune cell infiltration, which may have alleviated the severity of ALI of obese mice.

Prevalence of hypovitaminosis D in COVID-19 patients in the intensive care unit

Background: The prevalence of hypovitaminosis D has not been studied in the Russian Federation for the group of patients with severe and extremely severe COVID-19 in the intensive care unit (ICU). Aims: To study the prevalence of hypovitaminosis D in patients with COVID-19 treated in the ICU and to determine the relationship between the vitamin D status and disease outcome. Methods: The retrospective study included 103 adult patients with severe and extremely severe COVID-19 hospitalized in the ICU. Results: 94% patients (n = 97) showed a significant decrease in the concentration of 25 (OH) D in their blood serum 11 ng/ml [7; 15 ng/ml]. 37% (n = 38) of patients showed vitamin D deficiency, 46% (n = 47) had severe vitamin D deficiency, 12% (n = 12) had vitamin D insufficiency, 5% (n = 6) had normal vitamin D levels. In the group of patients with vitamin D levels less than 10 ng/ml, the mortality rate was significantly higher than that in the group of patients with the levels of vitamin D exceeding 10 ng/ml (66% and 42%, p = 0.018). These two groups of patients also significantly differed in their age (p = 0.018), history of diabetes mellitus (p = 0.059), white blood cell count (p = 0.045), neutrophil to lymphocyte ratio (p = 0.017), D-dimer level (p = 0.05) and troponin T level (p = 0.054). Conclusion: A high incidence of vitamin D insufficiency in patients with COVID-19 treated in the ICU has been identified. Severe vitamin D deficiency was more often found in elderly patients with diabetes mellitus, and was associated with the increased mortality. The identified relationship of the vitamin D deficiency with the neutrophilic-lymphocytic index suggests an immuno-mediated effect on the outcome of patients with COVID-19.

The Effect of Vitamin D Supplementation on Clinical Outcomes for Critically Ill Patients: A Systemic Review and Meta-Analysis of Randomized Clinical Trials

Purpose: Vitamin D deficiency is a common scenario in critically ill patients and has been proven to be associated with poor outcomes. However, the effect of vitamin D supplementation for critically ill patients remains controversial. Thus, we conducted a meta-analysis to evaluate the effect of vitamin D supplementation among critically ill patients. Methods: Electronic databases PubMed, Embase, Scopus, and the Cochrane Library were searched for eligible randomized controlled trials between 2000 and January 2021. The primary outcome was overall mortality, and the secondary ones were the length of intensive care unit stay, the length of hospital stay, as well as the duration of mechanical ventilation. Subgroup analyses were performed to explore the treatment effect by type of admission, route of administration, dose of supplemented vitamin D, and the degree of vitamin D deficiency. Results: A total of 14 studies involving 2,324 patients were finally included. No effect on overall mortality was found between vitamin D supplementation and control group [odds ratio (OR), 0.73; 95% CI, 0.52-1.03; I ² = 28%]. The vitamin D supplementation reduced the length of intensive care unit stay [mean difference (MD), -2.25; 95% CI, -4.07 to -0.44, I ² = 71%] and duration of mechanical ventilation (MD, -3.47; 95% CI, -6.37 to -0.57, I ² = 88%). In the subgroup analyses, the vitamin D supplementation for surgical patients (OR, 0.67; 95% CI, 0.47-0.94; I ² = 0%) or through parenteral way (OR, 0.42; 95% CI, 0.22-0.82, I ² = 0%) was associated with reduced mortality. Conclusion: In critically ill patients, the supplementation of vitamin D has no effect on overall mortality compared to placebo but may decrease the length of intensive care unit stay and mechanical ventilation. Further trials are necessary to confirm our findings.

Prevalence and Impact of Vitamin D Deficiency in Critically Ill Cancer Patients Admitted to the Intensive Care Unit

Vitamin D deficiency is frequent in cancer patients and a risk factor for morbidity and mortality during critical illness. This single-center retrospective study analyzed 25-hydroxyvitamin D levels in critically ill cancer patients (n = 178; hematologic, n = 108; solid, n = 70) enrolled in a prospective ICU registry. The primary analysis was the prevalence of vitamin D deficiency (<20 ng/mL) and the severe deficiency (≤12 ng/mL). Secondary analyses included risk factors for vitamin D deficiency and its impact on ICU, hospital, and 1-year mortality. The prevalence of vitamin D deficiency and severe deficiency was 74% (95% CI: 67-80%) and 54% (95% CI: 47-61%). Younger age, relapsed/refractory disease, and a higher sepsis-related organ failure assessment (SOFA) score were independent risk factors for vitamin D deficiency (p < 0.05). After adjusting for relapsed/refractory disease, infection, the SOFA score, and the early need for life-supporting interventions, severe vitamin D deficiency was an independent predictor of hospital mortality (OR: 2.21, 95% CI: 1.03-4.72, p = 0.04) and 1-year mortality (OR: 3.40, 95% CI: 1.50-7.71, p < 0.01), but not of ICU mortality. Conclusion: Vitamin D deficiency is common in critically ill cancer patients requiring ICU admission, but its impact on short-term mortality in this group is uncertain. The observed association of severe vitamin D deficiency with the post-ICU outcome warrants clinical consideration and further study.

Hospital-Acquired Serum Ionized Calcium Derangements and Their Associations with In-Hospital Mortality

Background: The objective of this study was to report the incidence of in-hospital serum ionized calcium derangement and its impact on mortality. Methods: We included 12,599 non-dialytic adult patients hospitalized at a tertiary medical center from January 2009 to December 2013 with normal serum ionized calcium at admission and at least 2 in-hospital serum ionized calcium values. Using serum ionized calcium of 4.60–5.40 mg/dL as the normal reference range, in-hospital serum ionized calcium levels were categorized based on the presence of hypocalcemia and hypercalcemia in hospital. We performed logistic regression to assess the relationship of in-hospital serum ionized calcium derangement with mortality. Results: Fifty-four percent of patients developed new serum ionized calcium derangements: 42% had in-hospital hypocalcemia only, 4% had in-hospital hypercalcemia only, and 8% had both in-hospital hypocalcemia and hypercalcemia. In-hospital hypocalcemia only (OR 1.28; 95% CI 1.01–1.64), in-hospital hypercalcemia only (OR 1.64; 95% CI 1.02–2.68), and both in-hospital hypocalcemia and hypercalcemia (OR 1.73; 95% CI 1.14–2.62) were all significantly associated with increased in-hospital mortality, compared with persistently normal serum ionized calcium levels. Conclusions: In-hospital serum ionized calcium derangements affect more than half of hospitalized patients and are associated with increased in-hospital mortality.

Vitamin D levels in liver transplantation recipients and early postoperative outcomes: Prospective observational DLiverX study

BACKGROUND & AIMS

In critically ill patients with liver disease, vitamin D deficiency is associated with higher disease severity, increased frequency of infections, and worse outcomes. This study sought to describe the trend of vitamin D in orthotopic liver transplantation (OLT) recipients and its association with outcomes.

METHODS

Prospective observational study of 67 consecutive OLT recipients enrolled between September, 2016 and August, 2017 at IRCCS-ISMETT, Palermo (Italy). Trend of vitamin D levels and potential factors influencing it levels were evaluated through a generalized linear mixed regression model.

RESULTS

Sixty-four (95.5%) recipients were vitamin D deficient (<20 ng/ml), with a median value of 8.8 ng/ml [6.2-12.9], and forty-seven of these (70.1%) showed severe deficiency (<12 ng/ml) at baseline, 7.9 ng/ml [5.4-8.9]. The baseline vitamin D showed an inverse correlation with liver disease severity: Child-Pugh, MELD score, bilirubin, INR, and organ failure (p < 0.01) at baseline. Vitamin D increased on postoperative day (POD) 28 compared with POD1: +4.5 ng/ml, C.I. 95% 3.6-5.3 ng/ml, p < 0.01. Lower baseline vitamin D, donor age, transfusion of fresh frozen plasma (negative impact, all p < 0.05), and intra-operative bypass (positive impact at POD 28, p < 0.01) were associated with variation of vitamin D levels after transplantation. Incomplete graft recovery was associated with lower vitamin D on POD28: 8.2 ± 4.4 versus 13.8 ± 9.4 ng/ml, p < 0.01; the odds ratio (OR) was 0.84; CI 95% 0.73-0.97, p = 0.014. The OR for infections within POD 28 was inversely associated with baseline vitamin D: 0.87; CI 95% 0.79-0.98, p = 0.02, and with vitamin D level at baseline <12 ng/ml: OR 6.44; CI 95% 1.66-24.94; p < 0.01.

CONCLUSIONS

Preoperative Vitamin D is correlated with disease severity, and was highly associated with invasive infection in the first 28 PODs. After OLT, the value on POD 28 had a strong association with graft function.

Hypocalcemia in Covid-19: A Prognostic Marker for Severe Disease

BACKGROUND & OBJECTIVE

Previous studies have addressed the electrolyte abnormalities such as hypocalcemia in COVID-19 patients. We aimed to compare the laboratory findings especially the electrolyte levels among COVID-19 patients and healthy controls and evaluate their prognostic values.

METHODS

This case-control study included 91 COVID-19 patients and 169 healthy individuals. Their laboratory parameters including electrolytes, albumin, liver enzymes, complete blood count, vitamin D, and parathyroid hormone (PTH) were compared. We also analyzed the association between these markers and the major outcomes including severity, mortality and hospitalization.

RESULTS

Among patients with COVID-19, 59.3% of the patients had hypocalcemia on admission while in control group only 32.5% had low calcium level (OR=3.02, 95% CI: 1.79-5.13, P<0.001). The rates of death and ICU admission were significantly higher among the patients in hypocalcemic group than those of eucalcemic group (85.7% vs 14.3% and 33.3% Vs 9.1%, respectively). However, there was no significant difference in the mean PTH and vitamin D levels between the two groups. In terms of the severity of the infection, 74.1% of patients in hypocalcemic group had a severe infection while 24.3% of the patients in eucalcemic group were diagnosed with severe infection (OR=8.89, 95% CI: 3.38-23.37, P<0.001).

CONCLUSION

Patients with COVID-19 may present with considerable laboratory abnormalities including hypocalcemia. The hypocalcemia would be also associated with worse major clinical outcome and higher mortality risk.

Serum vitamin D binding protein level, but not serum total, bioavailable, free vitamin D, is higher in 30-days survivors than in nonsurvivors with sepsis

The prognostic value of 3 types (total, bioavailable, and free) of 25-hydroxy vitamin D [25(OH)D] and vitamin D binding protein (VDBP) in patients with sepsis is unknown. The aim of this study was to evaluate the association of levels of those 3 types of 25(OH) D and VDBP with 30-day mortality in patients with sepsis. From March to December 2018, patients diagnosed with sepsis and admitted to the medical intensive care unit were enrolled, prospectively. We measured total 25(OH)D and VDBP levels, performed GC genotyping for the polymorphisms rs4588 and rs7041, and calculated bioavailable and free 25(OH)D levels. Total, bioavailable, and free 25(OH)D levels did not differ in 30-days nonsurvivors and survivors. Serum VDBP level was significantly higher in survivors than nonsurvivors (138.6 ug/mL vs 108.2 ug/mL, P = .023) and was associated with 30-day mortality in univariate but not multivariate analysis. VDBP polymorphisms and allele frequencies were not statistically different between the groups. Serum VDBP level was significantly higher in survivors than nonsurvivors over 30-days mortality in septic patients. However, 3 types (total, bioavailable, and free) of 25(OH)D levels did not differ between the survivors and nonsurvivors group.

Mechanistic study of the cause of decreased blood 1,25-Dihydroxyvitamin D in sepsis

Background

Vitamin D deficiency, determined by blood levels of 25-hydroxyvitamin D [25(OH) D, i.e. the major vitamin D form in blood], has been shown to associate with all-cause mortalities. We recently demonstrated that blood levels of 1,25-dihydroxyvitamin D [1,25(OH)₂D, i.e. the active vitamin D] were significantly lower in non-survivors compared to survivors among sepsis patients. Unexpectedly, despite the well documented roles of 1,25(OH)₂D in multiple biological functions such as regulation of immune responses, stimulation of antimicrobials, and maintenance of barrier function, 1,25(OH)₂D supplementation failed to improve disease outcomes. These previous findings suggest that, in addition to 1,25(OH)₂D deficiency, disorders leading to the 1,25(OH)₂D deficiency also contribute to mortality among sepsis patients. Therefore, this study investigated the mechanisms leading to sepsis-associated 1,25(OH)₂D deficiency.

Methods

We studied mechanisms known to regulate kidney 25-hydroxylvitamin D 1α-hydroxylase which physiologically catalyzes the conversion of 25(OH) D into 1,25(OH)₂D. Such mechanisms included parathyroid hormone (PTH), insulin-like growth factor 1 (IGF-1), fibroblast growth factor 23 (FGF-23), and kidney function.

Results

We demonstrated in both human subjects and mice that sepsis-associated 1,25(OH)₂D deficiency could not be overcome by increased production of PTH which stimulates 1α-hydroxylase. Further studies showed that this failure of PTH to maintain blood 1,25(OH)₂D levels was associated with decreased blood levels of IGF-1, increased blood levels of FGF-23, and kidney failure. Since the increase in blood levels of FGF-23 is known to associate with kidney failure, we further investigated the mechanisms leading to sepsis-induced decrease in blood levels of IGF-1. Our data showed that blood levels of growth hormone, which stimulates IGF-1 production in liver, were increased but could not overcome the IGF-1 deficiency. Additionally, we found that the inability of growth hormone to restore the IGF-1 deficiency was associated with suppressed expression and signaling of growth hormone receptor in liver.

Conclusions

Because FGF-23 and IGF-1 have multiple biological functions besides their role in regulating kidney 1α-hydroxylase, our data suggest that FGF-23 and IGF-1 are warranted for further investigation as potential agents for the correction of 1,25(OH)₂D deficiency and for the improvement of survival among sepsis patients.

Admission 25-Hydroxyvitamin D Levels Are Associated With Functional Status at Time of Discharge from Intensive Care Unit in Critically Ill Surgical Patients

BACKGROUND

Vitamin D status is associated with length of stay (LOS) and discharge destination in critically ill patients. To further understand this relationship, we investigated whether admission 25-hydroxyvitaminD (25OHD) levels are associated with discharge functional status in the intensive care unit (ICU).

METHODS

In this retrospective study, data from 2 surgical ICUs at a large teaching hospital were analyzed. 25OHD levels were measured within 24 hours of ICU admission and Functional Status Score for the ICU (FSS-ICU) was calculated within 24 hours of ICU discharge for all patients. To investigate the association of vitamin D status with FSS-ICU, we constructed linear and logistic regression models, controlling for body mass index, Nutrition Risk in the Critically Ill score, ICU LOS, and cumulative protein or caloric deficit during ICU admission.

RESULTS

Mean 25OHD level and FSS-ICU was 19 (SD 8) ng/mL and 17 (SD 4), respectively, in the analytic cohort (n = 300). Each unit increase in 25OHD level was associated with a 0.2 increment in FSS-ICU (β = .20; 95% CI 0.14-0.25). Patients with 25OHD levels <20 ng/mL had >3-fold risk of low FSS-ICU (<17) compared with patients with 25OHD >20 ng/mL (OR 3.45; 95% CI 1.96-6.08).

CONCLUSIONS

Our results suggest that vitamin D status at admission is associated with discharge FSS-ICU in critically ill surgical patients. Future studies are needed to validate our results, to build upon our findings, and to determine whether optimizing 25OHD levels can improve functional status and other important clinical outcomes in ICU patients.

Vitamin A deficiency in critically ill children with sepsis

BACKGROUND

Data that indicate vitamin A status in critically ill children with sepsis are sparse. The association between serum vitamin A levels and the clinical outcomes of sepsis has not been well assessed. The aim of this study was to assess the prevalence of vitamin A deficiency in critically ill children with sepsis and its association with clinical outcomes.

METHODS

Critically ill children with sepsis admitted to the pediatric intensive care unit were engaged in this prospective study. Sex- and age-matched approximate-health children from the Department of Pediatric Surgery were enrolled as the control group. Blood samples were collected from all patients in the first 24 h of admission for the measurement of serum vitamin A status. We compared vitamin A status between the sepsis group and the control group. In addition, we compared the clinical characteristics of the two subgroups of septic patients with vitamin A deficiency and those without vitamin A deficiency. Univariate and multivariable methods were used to evaluate the association between vitamin A deficiency and septic shock.

RESULTS

One hundred sixty septic children and 49 approximate-health children were enrolled in this study. Vitamin A deficiency was found in 94 (58.8%) subjects in the study group and 6 (12.2%) subjects in the control group (P < 0.001). In septic patients, 28-day mortality and hospital mortality in patients with vitamin A deficiency were not significantly higher than that in patients without vitamin A deficiency (P > 0.05). However, vitamin A levels were inversely associated with higher PRISM scores in septic children with VAD (r = - 0.260, P = 0.012). Vitamin A deficiency was associated with septic shock with an unadjusted odds ratio (OR) of 3.297 (95% confidence interval (CI), 1.169 to 9.300; P = 0.024). In a logistic model, vitamin A deficiency (OR, 4.630; 95% CI, 1.027-20.866; P = 0.046), procalcitonin (OR, 1.029; 95% CI, 1.009-1.048; P = 0.003), and the Pediatric Risk of Mortality scores (OR, 1.132; 95% CI, 1.009-1.228; P = 0.003) were independently associated with septic shock.

CONCLUSION

The prevalence of vitamin A deficiency was high in children with sepsis. Vitamin A deficiency may be a marker of mortality in critically ill children with sepsis.

TRIAL REGISTRATION

Clinicaltrials.gov , NCT03598127.

Clinical Nutrition in Critical Care Medicine - Guideline of the German Society for Nutritional Medicine (DGEM)

PURPOSE

Enteral and parenteral nutrition of adult critically ill patients varies in terms of the route of nutrient delivery, the amount and composition of macro- and micronutrients, and the choice of specific, immune-modulating substrates. Variations of clinical nutrition may affect clinical outcomes. The present guideline provides clinicians with updated consensus-based recommendations for clinical nutrition in adult critically ill patients who suffer from at least one acute organ dysfunction requiring specific drug therapy and/or a mechanical support device (e.g., mechanical ventilation) to maintain organ function.

METHODS

The former guidelines of the German Society for Nutritional Medicine (DGEM) were updated according to the current instructions of the Association of the Scientific Medical Societies in Germany (AWMF) valid for a S2k-guideline. According to the S2k-guideline classification, no systematic review of the available evidence was required to make recommendations, which, therefore, do not state evidence- or recommendation grades. Nevertheless, we considered and commented the evidence from randomized-controlled trials, meta-analyses and observational studies with adequate sample size and high methodological quality (until May 2018) as well as from currently valid guidelines of other societies. The liability of each recommendation was described linguistically. Each recommendation was finally validated and consented through a Delphi process.

RESULTS

In the introduction the guideline describes a) the pathophysiological consequences of critical illness possibly affecting metabolism and nutrition of critically ill patients, b) potential definitions for different disease phases during the course of illness, and c) methodological shortcomings of clinical trials on nutrition. Then, we make 69 consented recommendations for essential, practice-relevant elements of clinical nutrition in critically ill patients. Among others, recommendations include the assessment of nutrition status, the indication for clinical nutrition, the timing and route of nutrient delivery, and the amount and composition of substrates (macro- and micronutrients); furthermore, we discuss distinctive aspects of nutrition therapy in obese critically ill patients and those treated with extracorporeal support devices.

CONCLUSION

The current guideline provides clinicians with up-to-date recommendations for enteral and parenteral nutrition of adult critically ill patients who suffer from at least one acute organ dysfunction requiring specific drug therapy and/or a mechanical support device (e.g., mechanical ventilation) to maintain organ function. The period of validity of the guideline is approximately fixed at five years (2018-2023).

Serum vitamin D level was not associated with severity of ventilator associated pneumonia

BACKGROUND AND OBJECTIVE

Vitamin D deficiency is considered one of the most common nutritional deficiencies associated with weakened immune system and increased likelihood of sepsis. The current study was conducted to investigate the association between serum vitamin D level and the severity and prognosis of ventilator associated pneumonia (VAP) in inpatients in intensive care unit (ICU).

METHODS

Eighty-four consecutive patients with VAP were enrolled in this observational, prospective study conducted in the ICU of Besat Hospital, Hamadan. The patients were examined for serum 25-hydroxyvitamin D (vitD3) level and VAP severity and prognosis. Clinical pulmonary infection score was used for the diagnosis, and Sequential Organ Failure Assessment (SOFA) Score was used to determine the severity of VAP.

RESULTS

Low level serum vitD3 (under 30 ng/mL) was found in 66 (78.6%) patients. In this series of VAP patients, there were no significant differences in blood culture results, 14 and 28-day sepsis-associated mortality, mechanical ventilation duration, or SOFA Score on days 3, 7, and 14 between the low level and normal level vitD3 patients (p > 0.05).

CONCLUSION

Serum vitD3 level was not associated with mortality from VAP or complications due to sepsis in the inpatients in the ICU.

Vitamin D status and supplementation in adult patients receiving extracorporeal membrane oxygenation

The prevalence of vitamin D deficiency in critical illness is known to be high and associated with adverse clinical outcomes. Patients receiving extracorporeal membrane oxygenation (ECMO) may be at increased risk of vitamin D deficiency due to high severity of acute illness. Challenges with drug dosing in ECMO patients are recognised due to increased volume of distribution and drug absorption to circuit components. To describe the prevalence of vitamin D deficiency in ECMO patients and the effect of intramuscular dosing of cholecalciferol on levels of vitamin D metabolites, and to compare these data with intensive care unit (ICU) patients not receiving ECMO, two prospective studies were performed sequentially: an observational study of 100 consecutive ICU patients and an interventional study assessing effects of intramuscular cholecalciferol in 50 ICU patients. The subgroup of patients who required ECMO support in each of these studies was analysed and compared to patients who did not receive ECMO. Twenty-four ECMO patients, 12 from the observational study and 12 from the interventional study (who received intramuscular cholecalciferol) were studied-21/24 (88%) ECMO patients were vitamin D deficient at baseline compared to 65/126 (52%) of non-ECMO patients (<i>P</i>=0.006). Of the 12 ECMO patients who received cholecalciferol, six patients (50%) achieved correction of deficiency compared to 36/38 (95%) non-ECMO patients (<i>P</i>=0.001). The prevalence of vitamin D deficiency is higher in ECMO patients compared to other critically ill adults. Correction of deficiency with single dose cholecalciferol is not reliable; higher or repeated doses should be considered to correct deficiency.

Vitamin D Supplementation in Mechanically Ventilated Patients in the Medical Intensive Care Unit

BACKGROUND

The utility of vitamin D (VITD) supplementation during critical illness and whether it may alter outcomes, including mortality and ventilator-free days, is unclear. We performed a retrospective cohort study in a generalizable population to investigate this question.

METHODS

We included all mechanically ventilated adults admitted to the medical intensive care unit (ICU) service at a tertiary center from 2009 to 2012 who were in the ICU for at least 72 hours. Patients were grouped as having received or not received VITD at any time during the first 7 days of their ICU stay, and we adjusted for the following covariates with multivariable analyses: simplified acute physiology score, age, gender, admission diagnosis, race/ethnicity, admission season, admission day of the week, and VITD supplementation prior to admission.

RESULTS

Among the 610 included patients, 281 received VITD, and 329 did not. There were no differences in outcomes between these groups. However, we did find significantly more ventilator-free days (21.0±2.6 [adjusted mean days±standard error] vs 17.6±2.4, P=0.04) and ICU-free days (18.5±2.5 vs 16.3±2.3, P=0.03) in patients who were taking VITD prior to admission (n=91) vs those who were not (n=519). No patients who were taking VITD before admission died vs 34.5% of those who were not (estimated odds ratio=4.9×10^-7 , 95% CI=3.1×10^-7 to 7.5×10^-7 , P<0.0001).

CONCLUSION

These results suggest that VITD supplementation during critical illness may not provide benefit and that further research investigating potential supplementation in ambulatory patients at high risk of ICU admission (eg, severe underlying chronic disease) is warranted.

Vitamin D and critical illness: what endocrinology can learn from intensive care and vice versa

The prevalence of vitamin D deficiency in intensive care units ranges typically between 40 and 70%. There are many reasons for being or becoming deficient in the ICU. Hepatic, parathyroid and renal dysfunction additionally increases the risk for developing vitamin D deficiency. Moreover, therapeutic interventions like fluid resuscitation, dialysis, surgery, extracorporeal membrane oxygenation, cardiopulmonary bypass and plasma exchange may significantly reduce vitamin D levels. Many observational studies have consistently shown an association between low vitamin D levels and poor clinical outcomes in critically ill adults and children, including excess mortality and morbidity such as acute kidney injury, acute respiratory failure, duration of mechanical ventilation and sepsis. It is biologically plausible that vitamin D deficiency is an important and modifiable contributor to poor prognosis during and after critical illness. Although vitamin D supplementation is inexpensive, simple and has an excellent safety profile, testing for and treating vitamin D deficiency is currently not routinely performed. Overall, less than 800 patients have been included in RCTs worldwide, but the available data suggest that high-dose vitamin D supplementation could be beneficial. Two large RCTs in Europe and the United States, together aiming to recruit >5000 patients, have started in 2017, and will greatly improve our knowledge in this field. This review aims to summarize current knowledge in this interdisciplinary topic and give an outlook on its highly dynamic future.

Vitamin D deficiency and supplementation in critical illness-the known knowns and known unknowns

The burgeoning literature on vitamin D deficiency and supplementation over the past decade or so has generated a greater understanding of some areas but also an appreciation of the many areas of equipoise. This is particularly relevant in the field of critical care with the heterogeneous patient populations, the severity and duration of illness and the frequency of comorbid conditions.

This review aims to summarise the current knowledge base of vitamin D deficiency within the context of critical illness—“the known knowns”—and also highlight the areas of recognised uncertainty—“the known unknowns”. It acknowledges the fact that there may well be other knowledge gaps of clinical relevance of which we are currently unaware—“the unknown unknowns”.

Calcitriol trend following pediatric cardiac surgery and association with clinical outcome

BACKGROUND

Consistent with accepted practice in stable ambulatory populations, the majority of ICU research has evaluated vitamin D status using a single blood 25-hydroxyvitamin D (25(OH)D) level. Only a limited number of ICU studies have measured the active hormone, 1,25-dihydroxyvitamin D (calcitriol) and none have used change in calcitriol levels to evaluate axis functioning. The objective of this study was to describe the impact of Congenital Heart Disease (CHD) surgery on calcitriol levels and evaluate the relationship between change in postoperative levels and clinical course.

METHODS

Secondary analysis of a prospective cohort study of 56 children undergoing surgery for CHD.

RESULTS

Mean calcitriol levels dropped from 122.3 ± 69.1 pmol/L preoperatively to 65.3 ± 36.5 pmol/L (p < 0.0001) at PICU admission. The majority (61%, n = 34) were unable to increase calcitriol levels in the 48 h immediately following surgery. Post operative trend in calcitriol was inversely related to cardiovascular dysfunction, fluid requirements, ventilatory support and PICU length of stay (p < 0.01).

CONCLUSION

CHD patients had significant dysfunction of the vitamin D axis immediately postoperatively, demonstrated by both a significant intraoperative decline in calcitriol and inability to increase levels. Interventional research will be required to determine whether the use of calcitriol, in addition to cholecalciferol, reduces postoperative illness severity.

Association of Initial Serum Total Calcium Concentration with Mortality in Critical Illness

Background

Several studies have suggested that serum ionized calcium (iCa) is associated with mortality in critical illness. However, evidence regarding the predictive significance of serum total calcium (tCa) in critical illness remains scarce. The aim of this study was to assess the association of tCa levels with mortality in critical illness.

Methods

We employed the MIMIC-III v1.3 database. tCa was measured upon ICU admission and its relationship with mortality was determined using smooth curve fitting. The association between admission tCa levels and hospital mortality was determined using logistic regression.

Results

Inclusion criteria were met by 44,886 critically ill patients. A U-shaped pattern was observed between tCa and hospital mortality. Similar trends were observed for hospital mortality when quintiles were used to group patients according to tCa. In multivariate analysis, adjusted for age and sex, the model indicated that admission tCa levels ⩽7.6mg/dl, 7.7-8.1mg/dl, and ⩾9.0mg/dl were associated with an increase in mortality when compared to the reference level (8.6-9.0mg/dl). However, adjusted for more clinical characteristics, tCa was not associated with hospital mortality.

Conclusions

The relationship between tCa and hospital mortality followed a ''U" shaped curve. tCa had certain prognostic value in critically ill patients, but it had no independent association with hospital mortality.

Vitamin D status and its influence on outcomes following major burn injury and critical illness

Vitamin D deficiency is common among the general population. It is also observed in up to 76% of critically ill patients. Despite the high prevalence of hypovitaminosis D in critical illness, vitamin D is often overlooked by medical staff as the clinical implications and consequences of vitamin D deficiency in acute contexts remain to be fully understood. Vitamin D has a broad range of pleotropic effects on various processes and systems including the immune-inflammatory response. 1α,25-dihydroxyvitamin D (1,25(OH)₂D), has been shown to promote a tolerogenic immune response limiting deleterious inflammatory effects, modulation of the innate immune system, and enhancement of anti-microbial peptides. Vitamin D deficiency is frequently observed in critically ill patients and has been related to extrinsic causes (i.e., limited sunlight exposure), magnitude of injury/illness, or the treatment started by medical doctors including fluid resuscitation. Low levels of vitamin D in critically ill patients have been associated with sepsis, organ failure, and mortality. Despite this, there are subpopulations of critical illness, such as burn patients, where the literature regarding vitamin D status and its influence on outcomes remain insufficient. Thermal injury results in damage to both burned and non-burned tissues, as well as induces an exaggerated and persistent immune-inflammatory and hypermetabolic response. In this review, we propose potential mechanisms in which burn injury affects the vitamin D status and summarizes current literature investigating the influence of vitamin D status on outcomes. In addition, we reviewed the literature and trials investigating vitamin D supplementation in critically ill patients and discuss the therapeutic potential of vitamin D supplementation in burn and critically ill patients. We also highlight current limitations of studies that have investigated vitamin D status and supplementation in critical illness. Thermal injury influences vitamin D status. More studies investigating vitamin D depletion in burn patients and its influence on prognosis, via standardized methodology, are required to reach definitive conclusions and influence clinical practice.

Association of admission serum levels of vitamin D, calcium, Phosphate, magnesium and parathormone with clinical outcomes in neurosurgical ICU patients

To evaluate the association of admission serum levels of 25(OH)D, parathormone and the related electrolytes with severity of illness and clinical outcomes in neurosurgical critically ill patients, serum levels of 25(OH)D, parathormone, calcium, magnesium, and phosphate, along with APACHE II score were measured for 210 patients upon admission. Mean serum 25(OH)D was 21.1 ± 7.4 ng/mL. 25(OH)D deficiency (less than 20 ng/dL) and elevated serum parathormone level were found in 47.6% and 38% of patients respectively. Hypocalcaemia, hypophosphatemia, hypomagnesaemia and hypermagnesaemia were found in 29.5%, %63.8, 41.9% and 27.6% of patients respectively. The APACHE II score was significantly correlated with serum levels of 25(OH)D, parathormone, calcium, and phosphate. Multivariate regression analysis adjusted by other risk factors showed that among all clinical outcomes, admission hypovitaminosis D was associated with longer duration of ICU stay and a high admission of parathormone was associated with in ICU mortality. We concluded that disorders of admission serum levels of 25(OH)D, parathormone, calcium, magnesium, and phosphate are related to the presence of multiple causal factors such as severity of disease and are not independently associated with clinical outcomes. Most often they are normalize spontaneously with resolution of the disease process.

Oxidative stress in critically ill ventilated adults: effects of vitamin D3 and associations with alveolar macrophage function

Background

Disruptions in redox balance lead to oxidative stress, a promoter of morbidity in critical illness. This study aimed to: 1) characterize the plasma and alveolar thiol/disulfide redox pools, 2) examine their associations with alveolar macrophage phagocytosis, and 3) determine the effect of high dose vitamin D₃ on plasma thiol/disulfide redox.

Methods

Subjects were 30 critically ill, ventilated adults in a double-blind randomized trial of high-dose (250 000 or 500 000 IU) vitamin D₃ or placebo. Baseline bronchoalveolar lavage fluid (BALF) samples were analyzed for determination of alveolar phagocytosis index (PI) and for concentrations of glutathione (GSH), glutathione disulfide (GSSG), cysteine (Cys), cystine (CySS), and their respective redox potentials (EhGSSG and EhCySS). Plasma redox outcomes were assessed at baseline and days 7 and 14.

Results

Baseline plasma Cys was inversely associated with alveolar PI (ρ = −0.69, P=0.003), and E_hCySS was positively associated with PI (ρ = 0.61, P=0.01). Over time, among all subjects there was an increase in plasma GSH levels and a decrease in E_hGSSG (P<0.01 for both), with no difference by treatment group. Vitamin D₃ decreased oxidized plasma GSSG to a more normal state (P for group × time=0.009).

Conclusions

Oxidative stress indicators were positively associated with alveolar macrophage phagocytic function in acutely ill ventilated adults. High-dose vitamin D₃ decreased plasma GSSG concentrations, which suggests that vitamin D can possibly improve the oxidative stress environment.

Parathyroid hormone as a marker for hypoperfusion in trauma: A prospective observational study

BACKGROUND

Hyperparathyroidism is common in critical illness. Intact parathyroid hormone has a half-life of 3 minutes to 5 minutes due to rapid clearance by the liver, kidneys, and bone. In hemorrhagic shock, decreased clearance may occur, thus making parathyroid hormone a potential early marker for hypoperfusion. We hypothesized that early hyperparathyroidism predicts mortality and transfusion in trauma patients.

METHODS

A prospective observational study was performed at a Level I trauma center in consecutive adult patients receiving the highest level of trauma team activation. Parathyroid hormone and lactic acid were added to the standard laboratory panel drawn in the trauma bay on arrival, before the administration of any blood products. The primary outcomes assessed were transfusion in 24 hours and mortality.

RESULTS

Forty-six patients were included. Median age was 47 years, 82.6% were men, 15.2% suffered penetrating trauma, and 21.7% died. Patients who were transfused in the first 24 hours (n = 17) had higher parathyroid hormone (182.0 pg/mL vs. 73.5 pg/mL, p < 0.001) and lactic acid (4.6 pg/mL vs. 2.3 pg/mL, p = 0.001). Patients who did not survive to discharge (n = 10) also had higher parathyroid hormone (180.3 pg/mL vs. 79.3 pg/mL, p < 0.001) and lactic acid (5.5 mmol/L vs. 2.5 mmol/L, p = 0.001). For predicting transfusion in the first 24 hours, parathyroid hormone has an area under the receiver operating characteristic curve of 0.876 compared with 0.793 for lactic acid and 0.734 for systolic blood pressure. Parathyroid hormone has an area under the receiver operating characteristic curve of 0.875 for predicting mortality compared with 0.835 for lactic acid and 0.732 for systolic blood pressure.

CONCLUSION

Hyperparathyroidism on hospital arrival in trauma patients predicts mortality and transfusion in the first 24 hours. Further research should investigate the value of parathyroid hormone as an endpoint for resuscitation.

LEVEL OF EVIDENCE

Prognostic, level II.

Study protocol for a phase II dose evaluation randomized controlled trial of cholecalciferol in critically ill children with vitamin D deficiency (VITdAL-PICU study)

BACKGROUND

Clinical research has recently demonstrated that vitamin D deficiency (VDD) is highly prevalent in the pediatric intensive care unit (PICU) and associated with worse clinical course. Multiple adult ICU trials have suggested that optimization of vitamin D status through high-dose supplementation may reduce mortality and improve other clinically relevant outcomes; however, there have been no trials of rapid normalization in the PICU setting. The objective of this study is to evaluate the safety and efficacy of an enteral weight-based cholecalciferol loading dose regimen in critically ill children with VDD.

METHODS/DESIGN

The VITdAL-PICU pilot study is designed as a multicenter placebo-controlled phase II dose evaluation pilot randomized controlled trial. We aim to randomize 67 VDD critically ill children using a 2:1 randomization schema to receive loading dose enteral cholecalciferol (10,000 IU/kg, maximum of 400,000 IU) or a placebo solution. Participants, caregivers and outcome assessors will be blinded to allocation. Eligibility criteria include ICU patient, aged 37 weeks to 18 years, expected ICU length of stay more than 48 h, anticipated access to bloodwork at 7 days, and VDD (blood total 25 hydroxyvitamin D < 50 nmol/L). The primary objective is to determine whether the dosing protocol normalizes vitamin D status, defined as a blood total 25(OH)D concentration above 75 nmol/L. Secondary objectives include an examination of the safety of the dosing regimen (e.g. hypercalcemia, hypercalciuria, nephrocalcinosis), measures of vitamin D axis function (e.g. calcitriol levels, immune function), and protocol feasibility (eligibility criteria, protocol deviations, blinding).

DISCUSSION

Despite significant observational literature suggesting VDD to be a modifiable risk factor in the PICU setting, there is no robust clinical trial evidence evaluating the benefits of rapid normalization. This phase II clinical trial will evaluate an innovative weight-based dosing regimen intended to rapidly and safely normalize vitamin D levels in critically ill children. Study findings will be used to inform the design of a multicenter phase III trial evaluating the clinical and economic benefits to rapid normalization. Recruitment for this trial was initiated in January 2016 and is expected to continue until November 30, 2017.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02452762.

Prevalence and association of vitamin D deficiency and mortality in patients with severe sepsis

Background

Vitamin D is a steroid prohormone that regulates body calcium and phosphate metabolism. Recent studies have shown an association between low vitamin D status and high mortality in patients admitted to intensive care units. To date, there are limited data available specifically about severely septic patients in medical units.

Objectives

To determine the prevalence of vitamin D deficiency in severely septic patients and its clinical outcomes, including mortality rate.

Methods

A prospective observational study was conducted to investigate the prevalence of vitamin D deficiency and its association with 30-day mortality in patients with severe sepsis. Patients admitted to medical wards at our hospital between November 2014 and March 2015 were included in the study. A 25-hydroxyvitamin D level <20 ng/mL was defined as vitamin D deficiency, and <12 ng/mL as severe deficiency. For an association analysis, the patients were grouped into deficient versus not deficient and severely deficient versus not severely deficient.

Results

One hundred and ten eligible patients were enrolled. A total of 83 patients (75%) had vitamin D deficiency and 42 (38%) had severe deficiency. Despite an insignificant higher 30-day hospital mortality rate in vitamin D deficient versus non-deficient groups (16% vs 4%, p=0.18), the differences were significant between the severely deficient versus non-severe groups (23% vs 4%, p=0.02). The odds ratio of the 30-day mortality rate was 4.83 (95% confidence interval [CI], 0.60–38.77, p=0.14) for vitamin D deficiency and 7.69 (95% CI, 2.00–29.55, p=0.003) for severe deficiency.

Conclusion

The prevalence of vitamin D deficiency was very high in three-quarters of patients with severe sepsis. A significant higher mortality rate was observed, particularly in patients with severe vitamin D deficiency.

Vitamin D kinetics in the acute phase of critical illness: A prospective observational study

PURPOSE

The objective of this study was to assess the vitamin D kinetics in critically ill patients by performing periodic serum vitamin D measurements in short time intervals in the initial phase of a critical illness.

MATERIALS AND METHODS

We performed vitamin D serum measurements: at admission and then in 12-hour time intervals. The minimum number of vitamin D measurements was 4, and the maximum was 8 per patient.

RESULTS

A total of 363 patients were evaluated for participation, and 20 met the inclusion criteria. All patients had an initial serum vitamin D level between 10.6 and 39ng/mL. Nineteen patients had vitamin D levels between 10 and 30ng/mL, which means that they had vitamin D insufficiency or deficiency, and only one patient had a normal vitamin D serum plasma level. We observed that the median of the vitamin D level decreases until the fourth measurement then stabilizes around the 4th and 5th measurement and then appears to increase unevenly. The highest drop is at the very beginning.

CONCLUSIONS

The vitamin D serum level is changeable in the initial phase of a critical illness. We hypothesize that the serum vitamin D concentration can mirror the severity of illness.

Bone Failure in Critical Illness

OBJECTIVES

The origin of systemic inflammatory response syndrome and multiple organ dysfunction syndrome is poorly understood but remains a fundamental concern in the ICU. This paper provides a critical appraisal on whether bone failure may represent an unrecognized component of systemic inflammatory response syndrome/multiple organ dysfunction syndrome.

DATA SOURCES, DATA SELECTION, AND DATA EXTRACTION

Search of the PubMed database and manual review of selected articles investigating bone pathophysiology in critical illness.

DATA SYNTHESIS

Bone hyperresorption is highly prevalent among critically ill patients. Bone breakdown releases numerous systemically active cytokines and bone-sequestered toxins, with the capacity to fuel inflammatory hypercytokinaemia and metabolic toxaemia. Anti-resorptive medication inhibits bone break down and preadmission anti-resorptive use is associated with superior survival among critically ill patients.

CONCLUSIONS

We propose that hyperresorptive bone failure is an unrecognised component of systemic inflammatory response syndrome/multiple organ dysfunction syndrome that is causal to critical illness progression. If this hypothesis is valid, bone preservative strategies could reduce the risk of osteoporosis/fractures among ICU survivors, as well as decreasing critical illness mortality.

Impact of high-dose vitamin D3 on plasma free 25-hydroxyvitamin D concentrations and antimicrobial peptides in critically ill mechanically ventilated adults

OBJECTIVES

High-dose vitamin D₃ increases plasma total 25-hydroxyvitamin D [25(OH)D] in critically ill, ventilated patients; however, to our knowledge, the effect on plasma levels of free (nonprotein-bound) 25(OH)D has not been investigated in critical illness. Moreover, the relationship of free 25(OH)D and the regulation of endogenous antimicrobial peptides (AMPs) remains unknown. The aims of this study were to determine in critically ill adults with respiratory failure the effect of previous high-dose regimens of vitamin D₃ on free 25(OH)D concentrations, the relationship of free 25(OH)D with circulating cathelicidin (LL-37) and human beta-defensin-2 (hBD-2), and the associations between plasma levels of free 25(OH)D and these AMPs to alveolar macrophage phagocytosis function.

METHODS

In a double blind, randomized controlled trial, critically ill ventilator-dependent adults (N = 30) received enteral vitamin D₃ (250,000 or 500,000 IU total over 5 d) or placebo. Plasma was obtained serially for concentrations of free 25(OH)D, LL-37, hBD-2, and expression of peripheral blood mononuclear cell human cationic antimicrobial protein (hCAP18) mRNA. Total 25(OH)D and LL-37 concentrations and alveolar macrophage phagocytosis were determined in bronchoalveolar lavage fluid.

RESULTS

Plasma concentrations of free 25(OH)D over time were correlated with total 25(OH)D levels (r= 0.82; P < 0.001). The increase in free 25(OH)D was greater with the 500 000 IU vitamin D₃ dose than with the lower dose. The percent change in mRNA expression of hCAP18 was positively associated with percent change in free 25(OH)D at days 7 and 14 (ρ = 0.48; P = 0.04 and ρ = 0.59; P = 0.03, respectively). Additionally, plasma LL-37 levels correlated with the percentage of alveolar macrophages exhibiting phagocytosis (ρ = 0.51; P = 0.04).

CONCLUSIONS

The present study found a dose-related increase in plasma free-25(OH)D levels, which was associated with increasing circulating mRNA expression of hCAP18 over time. There were no correlations between changes in total and free 25(OH)D against plasma LL-37 and hBD-2 concentrations. Larger studies appear warranted to determine the impact of high-dose vitamin D₃ administration on endogenous AMPs.

Vitamin D Deficiency and Parathyroid Response in Critically-ill Children: Association with Illness Severity and Clinical Outcomes

OBJECTIVE

To determine the prevalence of vitamin D deficiency in critically ill children, and to study its association with parathyroid response, severity of illness and clinical outcomes.

DESIGN

Prospective observational study.

SETTING

Medical Pediatric Intensive Care Unit of a tertiary care centre of Northern India.

PARTICIPANTS

154 children in-patients: August 2011-January 2013.

MAIN OUTCOME MEASURES

Vitamin D deficient children were (serum 25-hydroxy vitamin D <20 ug/mL) divided into parathyroid-responder [serum parathyroid hormone >65 pg/mL with 25(OH)D<20 ug/mL and/or calcium corrected for albumin <8.5 mg/dL] and non parathyroid-responder. Illness severity was assessed by Pediatric Index of Mortality-2 (PIM-2) score at admission. Biochemical parameters, illness severity scores and clinical outcomes were compared between parathyroid-responders and non-parathyroid-responders.

RESULTS

Vitamin D deficiency and hypocalcemia were observed in 125 (83.1%) and 91 (59%) children, respectively at admission. There were no differences in illness severity score at admission, mortality rate and length of stay between vitamin D-deficient children and 19.8% of non-vitamin D-deficient children. Among Vitamin D-deficient children, parathyroid-responders had higher PIM-2 score at admission compared to non-parathyroid-responder [12.8 (7.4,20.6) vs. 6.5 (2.5,12.2), P=0.01]. However, there were no differences in other clinical outcomes between two groups.

CONCLUSION

Critically ill children have high prevalence of vitamin D deficiency. Parathyroid gland response secondary to hypocalcemia or vitamin D defiency is impaired in critical illness.

Outcomes of Vitamin D Supplementation in Adults Who are Deficient and Critically Ill: A Review of the Literature

Vitamin D deficiency is known to be common in the general population and has been linked to all-cause mortality. The classically recognized role of vitamin D is its involvement in calcium and phosphorous homeostasis and bone health. Recent evidence suggests that vitamin D may also play a role in other nonskeletal processes, such as anti-proliferation, immunity, regulation of hormone section, and muscle strength. An extensive literature review of vitamin D and critical illness from 2000 to 2015 (PubMed and CINAL) produced multiple observational studies revealing a high prevalence of vitamin D deficiency in intensive care patients. Many of these studies have indicated that there is an association between vitamin D deficiency and clinical outcomes such as mortality, sepsis, duration of mechanical ventilation, and length of stay. This review article provides an overview of vitamin D physiology in adults, a summary of observational studies on vitamin D deficiency in critical illness, and an examination of the few clinical trials on vitamin D supplementation in intensive care patients.

[Vitamin D deficiency and morbimortality in critically ill paediatric patients]

OBJECTIVES

To determine the prevalence and risks factors of vitamin D deficiency, as well as its relationship with morbidity and mortality in a PICU.

MATERIAL AND METHODS

An observational prospective study in a tertiary children's University Hospital PICU conducted in two phases: i: cohorts study, and ii: prevalence study. The study included 340 critically ill children with ages comprising 6 months to 16 years old.

EXCLUSION CRITERIA

Chronic kidney disease, known parathyroid disorders, and vitamin D supplementation. Total 25-hydroxyvitamin D [25(OH)D] was measured in the first 48hours of admission to a PICU. Parathormone, calcium, phosphate, blood gases, blood count, C-reactive protein, and procalcitonin were also analysed. A record was also made of demographic features, characteristics of the episode, and complications during the PICU stay.

RESULTS

The overall prevalence rate of vitamin D deficiency was 43.8%, with a mean of 22.28 (95% CI 21.15-23.41) ng/ml. Patients with vitamin D deficiency were older (61 vs 47 months, P=.039), had parents with a higher level of academic studies (36.5% vs 20%, P=.016), were admitted more often in winter and spring, had a higher PRISM-III (6.8 vs 5.1, P=.037), a longer PICU stay (3 vs 2 days, P=.001), and higher morbidity (61.1% vs 30.4%, P<001) than the patients with sufficient levels of 25(OH)D. Patients who died had lower levels of 25(OH)D (14±8.81ng/ml versus 22.53±10.53ng/ml, P=.012). Adjusted OR for morbidity was 5.44 (95%CI; 2.5-11.6).

CONCLUSIONS

Vitamin D deficiency is frequent in critically ill children, and it is related to both morbidity and mortality, although it remains unclear whether it is a causal relationship or it is simply a marker of severity in different clinical situations.

Burden and Outcome of Vitamin D Deficiency Among Critically Ill Patients: A Prospective Study

BACKGROUND

Vitamin D deficiency is a prevalent condition among critically ill patients. Information about the relationship between vitamin D levels and outcomes in the intensive care unit (ICU) is sparse.

PURPOSE

To evaluate vitamin D status among critically ill patients and its relevance to severity of illness, ICU stay period, and mortality.

METHODS

This prospective multicenter study was conducted in the ICUs of Fayoum, Cairo, Alazhar, and Ain Shams university hospitals. All patients were subjected to interview questionnaire, laboratory investigation, vitamin D level assessment, and severity of illness evaluation using the Acute Physiologic Assessment and Chronic Health Evaluation II (APACHE II) score.

RESULTS

In total, 250 patients were included in the study. The median age was 62 (40-73) years, and most patients were male (52%). The median serum level of vitamin D was 19 (7-40.6). Vitamin D was deficient in 197 patients (78.8%) on admission. While we grouped the ICU patients as vitamin D deficient, insufficient, and sufficient, vitamin D-deficient patients had more severe diseases (mean APACHE II score, 44 ± 15; P = .014). Prolonged ICU stay was observed among the deficient group but with no significant association. The overall mortality rate was 6.8%; of these, 70.5% were vitamin D-deficient patients. However, logistic regression analysis demonstrated that vitamin D deficiency was not an independent risk factor for mortality.

CONCLUSION

Vitamin D insufficiency is common in critically ill patients (69%); it is associated with more severity of illness, but it is not an independent risk factor for longer ICU stay or mortality.

High Vitamin D-Binding Protein Concentration, Low Albumin, and Mode of Remission Predict Relapse in Crohn's Disease

BACKGROUND

Vitamin D (25(OH)D) deficiency occurs in active Crohn's disease (CD) and may be secondary to reduced sunlight exposure and oral intake. Vitamin D-binding protein (VDBP) levels, however, fluctuate less with season and sunlight. The aim, therefore, was to examine patients with CD in remission and determine any associations between VDBP, serum 25(OH)D, and the calculated free 25(OH)D concentrations with the risk of disease flare.

METHODS

Subjects were identified from prospectively maintained inflammatory bowel disease databases at 3 teaching hospitals in Australia. Patients were in steroid-free clinical remission at the time of blood draw and were followed for at least 12 months. Total and epimer-25(OH)D3, VDBP concentrations, and genotypes were determined.

RESULTS

A total of 309 patients with CD (46% men) met the inclusion criteria. A disease flare occurred in 100 (32.4%). Serum 25(OH)D3 was deficient (<50 nmol/L) in 36 (12%) and insufficient (50-75 nmol/L) in 107 (35%) patients. Total, free, and epimer-25(OH)D3 serum levels did not predict disease flare. Higher VDBP concentrations, however, significantly correlated with increased risk of disease flare (hazard ratio 1.2, 95% CI, 1.0-1.5). On multivariate analysis, VDBP concentration, low albumin, and medication-induced remission were significantly more associated with disease flare. VDBP genotypes were significantly associated with 25(OH)D and VDBP concentrations but not disease flare.

CONCLUSIONS

Vitamin D deficiency was uncommon in our patients with CD in remission, and serum 25(OH)D3 did not predict disease flare, whereas higher VDBP concentrations were significantly associated with disease flare. Further investigations to explore the possible mechanisms for this association are warranted.

Critically Ill Children Have Low Vitamin D-Binding Protein, Influencing Bioavailability of Vitamin D

RATIONALE

Vitamin D deficiency, often defined by total serum 25-hydroxyvitamin D (25[OH]D) <20 ng/ml, is common in critically ill patients, with associations with increased mortality and morbidity in the intensive care unit. Correction of vitamin D deficiency in critical illness has been recommended, and ongoing clinical trials are investigating the effect of repletion on patient outcome. The biologically active amount of 25(OH)D depends on the concentration and protein isoform of vitamin D-binding protein (VDBP), which is also an acute-phase reactant affected by inflammation and injury.

OBJECTIVES

We performed a secondary analysis of a cohort of critically ill children in which we reported a high rate of vitamin D deficiency, to examine how VDBP level and genotype would impact vitamin D status.

METHODS

We prospectively enrolled 511 children admitted to the pediatric intensive care unit over a 12-month period.

MEASUREMENTS AND MAIN RESULTS

We measured serum VDBP in 479 children. We genotyped single nucleotide polymorphisms rs7041 and rs4588 in the VDBP gene (GC) to determine haplotypes GC1F, GC1S, and GC2 in 178 subjects who consented, then calculated bioavailable 25(OH)D from serum 25(OH)D, VDBP, albumin, and GC haplotype. The median serum VDBP level was 159 μg/ml (interquartile range, 108-221), lower than has been reported in healthy children. Factors predicting lower levels in multivariate analysis included age <1 year, nonwhite race, being previously healthy, 25(OH)D <20 ng/ml and greater illness severity. In the subgroup that was genotyped, GC haplotype had the strongest association with VDBP level; carriage of one additional copy of GC1S was associated with a 37.5% higher level (95% confidence interval, 31.9-44.8; P < 0.001). Bioavailable 25(OH)D was also inversely associated with illness severity (r = -0.24, P < 0.001), and ratio to measured total 25(OH)D was variable and related to haplotype.

CONCLUSIONS

Physiologic deficiency of 25(OH)D in critical illness may be more difficult to diagnose, given that lower VDBP levels increase bioavailability. Treatment studies conducted on the basis of total 25(OH)D level, without consideration of VDBP concentration and genotype, may increase the risk of falsely negative results.

Changes in Bone Mineral Density in the Year after Critical Illness

RATIONALE

Critical illness may be associated with increased bone turnover and loss of bone mineral density (BMD). Prospective evidence describing long-term changes in BMD after critical illness is needed to further define this relationship.

OBJECTIVES

To measure the change in BMD and bone turnover markers (BTMs) in subjects 1 year after critical illness compared with population-based control subjects.

METHODS

We studied adult patients admitted to a tertiary intensive care unit (ICU) who required mechanical ventilation for at least 24 hours. We measured clinical characteristics, BTMs, and BMD during admission and 1 year after ICU discharge. We compared change in BMD to age- and sex-matched control subjects from the Geelong Osteoporosis Study.

MEASUREMENTS AND MAIN RESULTS

Sixty-six patients completed BMD testing. BMD decreased significantly in the year after critical illness at both femoral neck and anterior-posterior spine sites. The annual decrease was significantly greater in the ICU cohort compared with matched control subjects (anterior-posterior spine, -1.59%; 95% confidence interval, -2.18 to -1.01; P < 0.001; femoral neck, -1.20%; 95% confidence interval, -1.69 to -0.70; P < 0.001). There was a significant increase in 10-year fracture risk for major fractures (4.85 ± 5.25 vs. 5.50 ± 5.52; P < 0.001) and hip fractures (1.57 ± 2.40 vs. 1.79 ± 2.69; P = 0.001). The pattern of bone resorption markers was consistent with accelerated bone turnover.

CONCLUSIONS

Critically ill individuals experience a significantly greater decrease in BMD in the year after admission compared with population-based control subjects. Their bone turnover biomarker pattern is consistent with an increased rate of bone loss.

High Dose Vitamin D Administration in Ventilated Intensive Care Unit Patients: A Pilot Double Blind Randomized Controlled Trial

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First double blind RCT of vitamin D therapy in mechanically ventilated patients.

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Treatment with placebo, 250,000 IU or 500,000 IU enteral vitamin D3 was well tolerated.

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Significant increase in plasma 25(OH)D from baseline to day 7.

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Significant decrease in hospital length of stay for vitamin D3 treated subjects.

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No change in plasma LL-37 according to treatment group.

Background

There is a high prevalence of vitamin D deficiency in the critically ill patient population. Several intensive care unit studies have demonstrated an association between vitamin D deficiency [25-hydroxyvitamin D (25(OH)D) < 20 ng/mL] and increased hospital length of stay (LOS), readmission rate, sepsis and mortality.

Material and Methods

Pilot, double blind randomized control trial conducted on mechanically ventilated adult ICU patients. Subjects were administered either placebo, 50,000 IU vitamin D₃ or 100,000 IU vitamin D₃ daily for 5 consecutive days enterally (total vitamin D₃ dose = 250,000 IU or 500,000 IU, respectively). The primary outcome was plasma 25(OH)D concentration 7 days after oral administration of study drug. Secondary outcomes were plasma levels of the antimicrobial peptide cathelicidin (LL37), hospital LOS, SOFA score, duration of mechanical ventilation, hospital mortality, mortality at 12 weeks, and hospital acquired infection.

Results

A total of 31 subjects were enrolled with 13 (43%) being vitamin D deficient at entry (25(OH)D levels < 20 ng/mL). The 250,000 IU and 500,000 IU vitamin D₃ regimens each resulted in a significant increase in mean plasma 25(OH)D concentrations from baseline to day 7; values rose to 45.7 ± 19.6 ng/mL and 55.2 ± 14.4 ng/mL, respectively, compared to essentially no change in the placebo group (21 ± 11.2 ng/mL), p < 0.001. There was a significant decrease in hospital length of stay over time in the 250,000 IU and the 500,000 IU vitamin D₃ group, compared to the placebo group (25 ± 14 and 18 ± 11 days compared to 36 ± 19 days, respectively; p = 0.03). There was no statically significant change in plasma LL-37 concentrations or other clinical outcomes by group over time.

Conclusions

In this pilot study, high-dose vitamin D3 safely increased plasma 25(OH)D concentrations into the sufficient range and was associated with decreased hospital length of stay without altering other clinical outcomes.

Vitamin D Deficiency in Pediatric Critical Care

Vitamin D deficiency (VDD) is a well-established cause of pediatric bone and muscle disease. In addition, a role has been recognized for vitamin D in the health and stress response of other organs, including the cardiovascular, immune, and respiratory systems. As these organs are central to the development of and recovery from critical illness, VDD has been hypothesized to be a modifiable risk factor for ICU outcome. Over the past 5 years, a growing number of adult and pediatric critical care studies have investigated the prevalence of VDD and its association with illness severity and outcome. The adult studies have recently been synthesized in systematic reviews, with results that convincingly suggest the need for trials to determine whether optimization of vitamin D status improves outcome. In contrast, the pediatric ICU and related literature has not been similarly synthesized. The goal of this review is to describe vitamin D metabolism, known biological mechanisms, potential role in pathophysiology, and summarize the available pediatric intensive care unit (PICU) studies reporting on prevalence of VDD deficiency and its association with outcome. The problems with currently approved supplementation approaches and alternative strategies are discussed, including evidence from available RCTs in adult ICU. Altogether the results suggest that critically ill children are at risk for VDD, and that VDD appears to be associated with a worse clinical course. Clinical trials evaluating novel approaches to testing for and supplementing vitamin D require exploration.