The Correlation between Vitamin D Levels and the Risk of Postoperative Recurrence in Crohn's Disease

Risk factors for endoscopic postoperative recurrence in patients with Crohn's Disease: a protocol for systematic review and meta-analysis

BACKGROUND

Crohn's disease (CD) is a chronic condition characterized by a high recurrence rate after surgery, which seriously affects the quality of life of patients. Many studies have explored the risk factors for the recurrence of CD after surgery, there is a lack of meta-analysis focusing on endoscopic postoperative recurrence (ePOR) as a clinical outcome. Therefore, this paper aims to identify the risk factors for ePOR in CD patients through systematic review and meta-analysis.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were searched for related literature from inception to 17th October 2023. Two researchers independently screened the literature and extracted information. Data analysis was performed using Stata18.0.

RESULTS

Twenty-three papers were included, with 5 case-control studies and 18 cohort studies. The National Institutes of Health quality assessment tool rated 17 studies as good and 6 studies as fair. The sample size of the 23 studies ranged from 40 to 346, and the number of patients with ePOR ranged from 23 to 169. The results of multivariate meta-analysis showed that smoking [OR = 2.06, 95% CI (1.65, 2.57), P = 0.0001], previous ileocolonic resection [OR = 1.71, 95% CI (1.23, 2.38), P = 0.002], disease localization at ileocolic resection [OR = 2.68, 95% CI (1.38, 5.22), P = 0.004], perianal disease [OR = 1.47, 95% CI (1.07, 2.03), P = 0.017], and anastomotic scattered ulcer [OR = 3.39, 95% CI (1.83, 6.28), P = 0.001] were risk factors for ePOR in CD patients. Postoperative prophylactic medication [OR = 0.53, 95% CI (0.38,0.75), P = 0.0001] was a protective factor for ePOR in CD patients.

CONCLUSIONS

This systematic review identified multiple factors for ePOR in CD patients, as well as a protective factor. However, the number of articles included was limited. More high-quality clinical studies are required to further validate the conclusions.

TRIAL REGISTRATION

This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42023483671).

Effectiveness of Vitamin D Supplementation on Disease Course in Inflammatory Bowel Disease Patients: Systematic Review With Meta-Analysis

BACKGROUND

The vitamin D role in bone metabolism is well known; however, recent evidence suggests the impact of vitamin D in immune modulation and its implications in immune-mediated diseases, including inflammatory bowel disease (IBD).

METHOD

We performed a systematic review with meta-analysis by a specific protocol (PROSPERO: CRD42022311184; March 2022, https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=311184). Randomized clinical trials involving IBD patients treated with vitamin D supplementation, compared with placebo, that evaluated the risk of clinical relapse and disease activity were included. Literature search was performed using Medline, Scopus, and Cochrane CENTRAL through January 2022.

RESULTS

Out of 1448 articles, 12 (11 full-texts and 1 abstract) were included. Seven randomized clinical trials reported data on the clinical relapse as dichotomous outcome, while 7 studies reported data on disease activity expressed as continuous variables. The pooled risk ratio of clinical relapse was 0.64 (95% confidence interval, 0.46-0.89; I2 = 25%) among 458 IBD patients. However, this seems to be solid only in Crohn's disease (CD) patients. In fact, only 2 studies, involving 67 patients with ulcerative colitis, were included in the analysis. CD patients in clinical remission had a strong significant risk reduction in clinical relapse (risk ratio, 0.47; 95% confidence interval, 0.27-0.82; I2 = 0%), suggesting that it could be a specific subgroup with maximum clinical benefit of vitamin D supplementation.

CONCLUSIONS

This meta-analysis shows that vitamin D supplementation can reduce the risk of clinical relapse in IBD patients, especially in CD patients in clinical remission. In a subgroup analysis, it was not significant (due to small number of studies and low number of patients), and well-powered studies are needed, in particular for ulcerative colitis patients.

Nutrition, Nutritional Status, Micronutrients Deficiency, and Disease Course of Inflammatory Bowel Disease

During the disease course, most Inflammatory Bowel Disease patients present a condition of malnutrition, undernutrition, or even overnutrition. These conditions are mainly due to suboptimal nutritional intake, alterations in nutrient requirements and metabolism, malabsorption, and excessive gastrointestinal losses. A suboptimal nutritional status and low micronutrient serum levels can have a negative impact on both induction and maintenance of remission and on the quality of life of Inflammatory Bowel Disease patients. We performed a systematic review including all the studies evaluating the connection between nutrition, nutrition status (including undernutrition and overnutrition), micronutrient deficiency, and both disease course and therapeutic response in Inflammatory Bowel Disease patients. This systematic review was performed using PubMed/MEDLINE and Scopus. Four main clinical settings concerning the effect of nutrition on disease course in adult Inflammatory Bowel Disease patients were analyzed (induction of remission, maintenance of remission, risk of surgery, post-operative recurrence, and surgery-related complications). Four authors independently reviewed abstracts and manuscripts for eligibility. 6077 articles were found; 762 duplicated studies were removed. Out of 412 full texts analyzed, 227 were included in the review. The evidence summarized in this review showed that many nutritional aspects could be potential targets to induce a better control of symptoms, a deeper remission, and overall improve the quality of life of Inflammatory Bowel Disease patients.

[Mechanism of action and exogenous supplementation of vitamin D in Crohn's disease]

Vitamin D can not only regulate calcium and phosphorus metabolism, but also exert an immunoregulatory effect. Vitamin D deficiency is common in patients with Crohn's disease (CD). Studies have shown that vitamin D is associated with CD and other autoimmune diseases and can improve the condition of patients with CD and promote their recovery by regulating intestinal immunity, repairing the intestinal mucosal barrier, inhibiting intestinal fibrosis, enhancing the response to infliximab, and regulating intestinal microbiota. Exogenous vitamin D supplementation can induce disease remission while increasing the serum level of vitamin D. However, only a few randomized, double-blind, and placebo-controlled trials have investigated the therapeutic effect of vitamin D in CD, and the optimal form of vitamin D supplementation, the specific dosage of vitamin D supplementation, and the optimal serum maintenance concentration of vitamin D remain to be clarified. This article mainly discusses the mechanism of action of vitamin D in CD and the beneficial effect of exogenous vitamin D supplementation on CD.

Immunomodulatory actions of vitamin D in various immune-related disorders: a comprehensive review

For many years, vitamin D has been acknowledged for its role in maintaining calcium and phosphate balance. However, in recent years, research has assessed its immunomodulatory role and come up with conflicting conclusions. Because the vitamin D receptor is expressed in a variety of immune cell types, study into the precise role of this molecule in diseases, notably autoimmune disorders, has been made possible. The physiologically activated version of vitamin D also promotes a tolerogenic immunological condition in addition to modulating innate and acquired immune cell responses. According to a number of recent studies, this important micronutrient plays a complex role in numerous biochemical pathways in the immune system and disorders that are associated with them. Research in this field is still relatively new, and some studies claim that patients with severe autoimmune illnesses frequently have vitamin D deficiencies or insufficiencies. This review seeks to clarify the most recent research on vitamin D's immune system-related roles, including the pathophysiology of major disorders.

Development and validation of a non-invasive biomarker-based model to identify endoscopic recurrences of Crohn's disease

BACKGROUND

Endoscopic recurrence is common in postoperative patients with Crohn's disease (CD). Monitoring endoscopic recurrence is important for selecting an appropriate treatment to prevent the development of postoperative disease. The aim of this study was to develop and validate a diagnostic model to identify endoscopic recurrence.

METHODS

This was a retrospective cohort study recruiting postoperative CD patients who underwent endoscopy at the First Affiliated Hospital, Sun Yat-sen University from January 2016 to June 2020. Endoscopic recurrence was defined as Rutgeerts score > i1. Thirty non-invasive biomarkers, including C-reactive protein, erythrocyte sedimentation rate, vitamin D, complete blood count, and biochemical blood indices, were used as candidate predictors to build a multivariate logistic regression diagnostic model. The predictive ability of the diagnostic models was assessed by receiving the area under the characteristic curve (AUC) and calibration plots, and internal validation was performed by the bootstrap method.

RESULTS

Two hundred and nineteen eligible patients were included in this study, and 135 (61.6%) patients had a postoperative endoscopic recurrence. The final diagnostic model included eight biomarkers with an AUC (95% confidence interval (CI)) of 0.796 (0.737-0.855) to identify endoscopic recurrence. The AUC, sensitivity, and specificity of this diagnostic model were 0.781 (0.780-0.782), 0.647 (0.643-0.651) and 0.811 (0.807-0.815), respectively, by internal validation. In addition, the diagnostic model exhibited good calibrability with calibration slope, calibration-in-the-large ('mean calibration') and Brier scores of 1.00, 0.00, and 0.175, respectively.

CONCLUSION

This non-invasive biomarker-based diagnostic model has an excellent ability to identify endoscopic recurrence in patients with CD. Application of the model to clinical practice to monitor postoperative patients may be helpful for patient management.

Vitamin D, infections and immunity

Vitamin D, best known for its role in skeletal health, has emerged as a key regulator of innate immune responses to microbial threat. In immune cells such as macrophages, expression of CYP27B1, the 25-hydroxyvitamin D 1α-hydroxylase, is induced by immune-specific inputs, leading to local production of hormonal 1,25-dihydroxyvitamin D (1,25D) at sites of infection, which in turn directly induces the expression of genes encoding antimicrobial peptides. Vitamin D signaling is active upstream and downstream of pattern recognition receptors, which promote front-line innate immune responses. Moreover, 1,25D stimulates autophagy, which has emerged as a mechanism critical for control of intracellular pathogens such as M. tuberculosis. Strong laboratory and epidemiological evidence links vitamin D deficiency to increased rates of conditions such as dental caries, as well as inflammatory bowel diseases arising from dysregulation of innate immune handling intestinal flora. 1,25D is also active in signaling cascades that promote antiviral innate immunity; 1,25D-induced expression of the antimicrobial peptide CAMP/LL37, originally characterized for its antibacterial properties, is a key component of antiviral responses. Poor vitamin D status is associated with greater susceptibility to viral infections, including those of the respiratory tract. Although the severity of the COVID-19 pandemic has been alleviated in some areas by the arrival of vaccines, it remains important to identify therapeutic interventions that reduce disease severity and mortality, and accelerate recovery. This review outlines of our current knowledge of the mechanisms of action of vitamin D signaling in the innate immune system. It also provides an assessment of the therapeutic potential of vitamin D supplementation in infectious diseases, including an up-to-date analysis of the putative benefits of vitamin D supplementation in the ongoing COVID-19 crisis.

Vitamin D in Inflammatory Bowel Diseases. Mechanisms of Action and Therapeutic Implications

(1) Background: Vitamin D is an immunoregulatory factor influencing intestinal homeostasis. Recent evidence supports a central role of this micronutrient in the course of Inflammatory Bowel Diseases (IBD). This narrative review aims to provide a general overview of the possible biological mechanisms of action of vitamin D and its therapeutic implications in IBD. (2) Methods: A systematic electronic search of the English literature up to October 2021 was performed using Medline and the Cochrane Library. Only papers written in English that analyzed the role of vitamin D in IBD were included. (3) Results: In vitro and animal studies reported that vitamin D signaling improves epithelial barrier integrity regulating the expression of several junctional proteins, defensins, and mucins, modulates the inflammatory response, and affects gut microbiome composition. Recent studies also suggest that vitamin D deficiency is highly prevalent among IBD patients and that low serum levels correlate with disease activity and, less clearly, with disease course. (4) Conclusions: An increasing body of evidence suggests some role of vitamin D in the pathophysiology of IBD, nonetheless the underlying mechanisms have been so far only partially elucidated. A strong correlation with disease activity has been reported but its implication in the treatment is still undefined. Thus, studies focused on this issue, the definition of vitamin D levels responsible for clinical effects, and the potential role of vitamin D as a therapeutic agent are strongly encouraged.

Vitamin D: Dosing, levels, form, and route of administration: Does one approach fit all?

The 4^th International Conference on Controversies in Vitamin D was held as a virtual meeting in September, 2020, gathering together leading international scientific and medical experts in vitamin D. Since vitamin D has a crucial role in skeletal and extra-skeletal systems, the aim of the Conference was to discuss improved management of vitamin D dosing, therapeutic levels and form or route of administration in the general population and in different clinical conditions. A tailored approach, based on the specific mechanisms underlying vitamin D deficiency in different diseases that were discussed, was recommended. Specifically, in comparison to healthy populations, higher levels of vitamin D and greater amounts of vitamin D were deemed necessary in osteoporosis, diabetes mellitus, obesity (particularly after bariatric surgery), and in those treated with glucocorticoids. Emerging and still open issues were related to target vitamin D levels and the role of vitamin D supplementation in COVID-19 since low vitamin D may predispose to SARS-CoV-2 infection and to worse COVID-19 outcomes. Finally, whereas oral daily cholecalciferol appears to be the preferred choice for vitamin D supplementation in the general population, and in most clinical conditions, active vitamin D analogs may be indicated in patients with hypoparathyroidism and severe kidney and liver insufficiency. Parenteral vitamin D administration could be helpful in malabsorption syndromes or in states of vitamin D resistance.Specific guidelines for desired levels of vitamin D should be tailored to the different conditions affecting vitamin D metabolism with the goal to define disease-specific normative values.