Nutritional Status and Its Detection in Patients with Inflammatory Bowel Diseases

The relationship between Glasgow Prognostic Score and hospital duration in patients with inflammatory bowel diseases

BACKGROUND AND OBJECTIVES

Both hypoalbuminemia and inflammation were common in patients with inflammatory bowel diseases (IBD), however, the combination of the two parameters on hospital duration re-mained unknown.

METHODS AND STUDY DESIGN

This is a retrospective two-centre study performed in two tertiary hospitals in Shanghai, China. Serum levels of C-Reactive Protein (CRP) and albumin (ALB) were measured within 2 days of admission. Glasgow prognostic score (GPS), based on CRP and ALB, was calculated as follows: point "0" as CRP <10 mg/L and ALB ≥35 g/L; point "1" as either CRP ≥10 mg/L or ALB <35 g/L; point "2" as CRP ≥10 mg/L and ALB <35 g/L. Patients with point "0" were classified as low-risk while point "2" as high-risk. Length of hospital stay (LOS) was defined as the interval between admission and discharge.

RESULTS

The proportion of low-risk and high-risk was 69.3% and 10.5% respectively among 3,009 patients (65% men). GPS was associated with LOS [β=6.2 d; 95% CI (confidence interval): 4.0 d, 8.4 d] after adjustment of potential co-variates. Each point of GPS was associated with 2.9 days (95% CI: 1.9 d, 3.9 d; ptrend<0.001) longer in fully adjusted model. The association was stronger in patients with low prealbumin levels, hypocalcaemia, and hypokalaemia relative to their counterparts.

CONCLUSIONS

GPS was associated with LOS in IBD patients. Our results highlighted that GPS could serve as a convenient prognostic tool associated with nutritional status and clinical outcome.

Mucocutaneous manifestations of inflammatory bowel disease

Mucocutaneous manifestations can be indicative of a variety of gastrointestinal diseases, and the dermatologist needs to know how to recognize them to refer the right patients to the gastroenterologist. Conversely, the gastroenterologist is often confronted with mucocutaneous lesions that raise the question of a possible association with a known digestive disease. Among the extra-intestinal manifestations of inflammatory bowel disease (IBD), mucocutaneous manifestations are the most common. This review will provide a breakdown by classifying them into 4 groups: 1) reactive manifestations, which include neutrophilic dermatoses, aphthous stomatitis, erythema nodosum, and vasculitis; 2) Crohn's disease-specific granulomatous skin lesions, which are histologically characterized by tuberculoid granulomas similar to those found in the gastrointestinal tract; 3) nutritional deficiency manifestations secondary to anorexia, malabsorption, loss, and drug interactions; and 3) a variety of autonomous autoimmune or inflammatory skin diseases. Dermatologists may also be involved in the management of the adverse effects of IBD treatments, especially the so-called "paradoxical" psoriatic eruptions.

Preoperative optimization: Review on nutritional assessment and strategies in IBD

Inflammatory bowel diseases (IBD), encompassing conditions like Crohn's disease and ulcerative colitis, present multifaceted challenges requiring a comprehensive management approach. Patients often necessitate a combination of medical therapy, surgical interventions, and nutritional support. Despite advancements in medical and dietary therapies, the prevalence of surgery remains high among the IBD population, alongside the persistent risk of malnutrition. Preoperative nutritional optimization has thus become a critical element in the perioperative pathway, given its association with improved surgical outcomes. However, standardized protocols for preoperative optimization of IBD patients are lacking, and available data are mainly retrospective. This review provides an overview of the current knowledge on preoperative nutritional screening and optimization in IBD patients and identifies avenues for future research and clinical practice. Interdisciplinary collaboration among healthcare professionals, including gastroenterologists, surgeons, dietitians, physiotherapists, and psychologists, is crucial for comprehensive preoperative nutritional management in IBD patients. By addressing the interplay between inflammation, malnutrition, and surgical risk, clinicians can strive to enhance surgical care and postoperative outcomes. In conclusion, while recognizing the importance of preoperative nutritional optimization in improving surgical outcomes for IBD patients, challenges persist in standardizing management protocols. Prospective studies are needed to establish such protocols and evaluate the effectiveness of different nutritional strategies.

Self-reported food intolerance, dietary supplement use and malnutrition in chronic inflammatory bowel diseases: Findings from a cross-sectional study in Lebanon

BACKGROUND/AIMS

Chronic inflammatory bowel diseases (IBDs), including Crohn's disease and ulcerative colitis are known for a combination of food intolerance, decreased oral intake, and malabsorption which all predispose patients to malnutrition and suboptimal dietary intake. The present study was conducted to 1) examine self-reported food intolerances and dietary supplement use 2) assess nutritional intake 3) assess the nutritional status and screen for malnutrition among patients with chronic inflammatory bowel disease (CIBD).

METHODS

48 patients with CIBDs (28 Crohn's disease, 15 ulcerative colitis and 7 with atypical forms of IBD) took part in this cross-sectional study. Participants completed a food frequency questionnaire targeting dietary intakes and food trends over time. A questionnaire about food intolerance was also used. The nutritional status of patients with CIBDs was evaluated by a detailed history (medical diagnosis and medications and supplements administered) and by using the subjective global assessment (SGA) tool. Anthropometric data including height, weight, and BMI with body composition assessment using automated scales and stadiometer, while Bio-impedancemetry was used to measure body fat and visceral fat. Statistical analysis was conducted using SPSS 27, employing mean values, standard deviations, absolute and relative frequencies and Pearson's chi-square test, with significance set at p ≤ 0.05.

RESULTS

Food intolerance was equally common in all the types of CIBD specifically for dairy products, spicy foods, and high-fiber food items (beans and raw vegetables). Individuals with CIBD were also complaining about meat and chicken products (68%), followed by alcohol and soda (64%) and fish and sea foods (59%). 17% of the patients were malnourished. A significant percentage of malnourished patients with CIBD had to follow a diet outside the flare, had a nutritional follow up, were currently taking corticosteroids and had a severe form of the disease compared to patients who were well nourished.

CONCLUSIONS

This study has contributed valuable insights into the understanding that some food items could be associated to periods of increased disease activity in CIBD patients and that awareness/intervention regarding nutrition must be provided by healthcare professionals (dietitians, physicians…) to decrease the need for second line therapy. In addition, this self-reported food intolerance paper gives an insight for patients on food items usually avoided by CIBD patients during flares.

The Effect of Protein Nutritional Support on Inflammatory Bowel Disease and Its Potential Mechanisms

Inflammatory bowel disease (IBD), a complex chronic inflammatory bowel disorder that includes Crohn's disease (CD) and Ulcerative Colitis (UC), has become a globally increasing health concern. Nutrition, as an important factor influencing the occurrence and development of IBD, has attracted more and more attention. As the most important nutrient, protein can not only provide energy and nutrition required by patients, but also help repair damaged intestinal tissue, enhance immunity, and thus alleviate inflammation. Numerous studies have shown that protein nutritional support plays a significant role in the treatment and remission of IBD. This article presents a comprehensive review of the pathogenesis of IBD and analyzes and summarizes the potential mechanisms of protein nutritional support in IBD. Additionally, it provides an overview of the clinical effects of protein nutritional support in IBD and its impact on clinical complications. Research findings reveal that protein nutritional support demonstrates significant benefits in improving clinical symptoms, reducing the risk of complications, and improving quality of life in IBD patients. Therefore, protein nutritional support is expected to provide a new approach for the treatment of IBD.

Impact of total parenteral nutrition v. exclusive enteral nutrition on postoperative adverse outcomes in patients with penetrating Crohn's disease undergoing surgical resection: a retrospective cohort study

Achieving optimal nutritional status in patients with penetrating Crohn's disease is crucial in preparing for surgical resection. However, there is a dearth of literature comparing the efficacy of total parenteral nutrition (TPN) v. exclusive enteral nutrition (EEN) in optimising postoperative outcomes. Hence, we conducted a case-matched study to assess the impact of preoperative EEN v. TPN on the incidence of postoperative adverse outcomes, encompassing overall postoperative morbidity and stoma formation, among penetrating Crohn's disease patients undergoing bowel surgery. From 1 December 2012 to 1 December 2021, a retrospective study was conducted at a tertiary centre to enrol consecutive patients with penetrating Crohn's disease who underwent surgical resection. Propensity score matching was utilised to compare the incidence of postoperative adverse outcomes. Furthermore, univariate and multivariate logistic regression analyses were conducted to identify the risk factors associated with adverse outcomes. The study included 510 patients meeting the criteria. Among them, 101 patients in the TPN group showed significant improvements in laboratory indicators at the time of surgery compared with pre-optimisation levels. After matching, TPN increased the occurrence of postoperative adverse outcomes (92·2 % v. 64·1 %, P = 0·001) when compared with the EEN group. In the multivariate analysis, TPN showed a significantly higher OR for adverse outcomes than EEN (OR = 4·241; 95 % CI 1·567-11·478; P = 0·004). The study revealed that penetrating Crohn's disease patients who were able to fulfil their nutritional requirements through EEN exhibited superior nutritional and surgical outcomes in comparison with those who received TPN.

Compound prebiotics as prophylactic and adjunctive treatments ameliorate DSS-induced colitis through gut microbiota modulation effects

The prophylactic and adjunctive impacts of compound prebiotics (CP), comprising galacto-oligosaccharides, fructo-oligosaccharides, and isomalto-oligosaccharides, on colitis remain unclear. This study aimed to elucidate the effects of CP on dextran sodium sulfate (DSS)-induced colitis via modulation of the gut microbiota. Mice received prophylactic CP (PCP) for three weeks and DSS in the second week. In the third week, therapeutic CP, mesalazine, and a combination of CP and mesalazine (CPM) were administered to mice with DSS-induced colitis. The administration of PCP and CPM was found to ameliorate colitis, as evidenced by increases in body weight and colon length, elevation of the anti-inflammatory cytokine IL-10, and reductions in the disease activity index, histological scores, and levels of pro-inflammatory cytokines in mice with DSS-induced colitis on days 14 or 21. Furthermore, an increase in the relative abundance of probiotics (Ligilactobacillus, Bifidobacterium, and Limosilactobacillus), alpha diversity indices, short-chain fatty acids (SCFA) contents, and microbial network complexity was observed following PCP or CPM treatment. Correlation analysis revealed positive associations between these probiotics and both SCFA and IL-10, and negative associations with pro-inflammatory cytokines. This study highlighted the potential of CP as novel prophylactic and adjunctive treatments for alleviating DSS-induced intestinal inflammation and maintaining gut microbiota homeostasis.

Sarcopenia as a Preoperative Risk Stratification Tool among Older Adults with Inflammatory Bowel Disease

Sarcopenia, defined as a loss of muscle mass and function, is a physiologic factor that has been implicated as a predictor of adverse postoperative outcomes in many older adult populations. However, data related to sarcopenia in older adults with inflammatory bowel disease (IBD) remain limited. Older adults with IBD are particularly vulnerable to adverse postoperative outcomes, in part, due to muscle depletion from systemic inflammation, malnutrition, and reduced physical activity. However, few patients undergo routine muscle evaluation as a part of preoperative assessment. Moreover, cut-off values for measures of sarcopenia in the literature are modeled after non-IBD populations. The lack of standardized measures and values for sarcopenia in the IBD patient population has led to heterogenous findings and a paucity of preoperative risk stratification tools. Therefore, we aim to explore the scope of sarcopenia as a preoperative risk stratification tool among older adults with IBD.

Navigating the Intersection: Sarcopenia and Sarcopenic Obesity in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs) are intricate systemic conditions that can extend beyond the gastrointestinal tract through both direct and indirect mechanisms. Sarcopenia, characterized by a reduction in muscle mass and strength, often emerges as a consequence of the clinical course of IBDs. Indeed, sarcopenia exhibits a high prevalence in Crohn's disease (52%) and ulcerative colitis (37%). While computed tomography and magnetic resonance imaging remain gold-standard methods for assessing muscle mass, ultrasound is gaining traction as a reliable, cost-effective, and widely available diagnostic method. Muscle strength serves as a key indicator of muscle function, with grip strength test emerging nowadays as the most reliable assessment method. In IBDs, sarcopenia may arise from factors such as inflammation, malnutrition, and gut dysbiosis, leading to the formulation of the 'gut-muscle axis' hypothesis. This condition determines an increased need for surgery with poorer post-surgical outcomes and a reduced response to biological treatments. Sarcopenia and its consequences lead to reduced quality of life (QoL), in addition to the already impaired QoL. Of emerging concern is sarcopenic obesity in IBDs, a challenging condition whose pathogenesis and management are still poorly understood. Resistance exercise and nutritional interventions, particularly those aimed at augmenting protein intake, have demonstrated efficacy in addressing sarcopenia in IBDs. Furthermore, anti-TNF biological therapies showed interesting outcomes in managing this condition. This review seeks to furnish a comprehensive overview of sarcopenia in IBDs, elucidating diagnostic methodologies, pathophysiological mechanisms, and clinical implications and management. Attention will also be paid to sarcopenic obesity, exploring the pathophysiology and possible treatment modalities of this condition.

From Gut to Brain: Uncovering Potential Serum Biomarkers Connecting Inflammatory Bowel Diseases to Neurodegenerative Diseases

Inflammatory bowel diseases (IBDs) are characterized by chronic gastrointestinal inflammation due to abnormal immune responses to gut microflora. The gut-brain axis is disrupted in IBDs, leading to neurobiological imbalances and affective symptoms. Systemic inflammation in IBDs affects the brain's inflammatory response system, hormonal axis, and blood-brain barrier integrity, influencing the gut microbiota. This review aims to explore the association between dysregulations in the gut-brain axis, serum biomarkers, and the development of cognitive disorders. Studies suggest a potential association between IBDs and the development of neurodegeneration. The mechanisms include systemic inflammation, nutritional deficiency, GBA dysfunction, and the effect of genetics and comorbidities. The objective is to identify potential correlations and propose future research directions to understand the impact of altered microbiomes and intestinal barrier functions on neurodegeneration. Serum levels of vitamins, inflammatory and neuronal damage biomarkers, and neuronal growth factors have been investigated for their potential to predict the development of neurodegenerative diseases, but current results are inconclusive and require more studies.

Calcium deficiency is associated with malnutrition risk in patients with inflammatory bowel disease

BACKGROUND AND AIM

Patients with inflammatory bowel disease (IBD) often have the condition of malnutrition, which can be presented as sarcopenia, micronutrient deficiencies, etc. Trace elements (magnesium, calcium, iron, copper, zinc, plumbum and manganese) belonging to micronutrients, are greatly vital for the assessment of nutritional status in humans. Trace element deficiencies are also the main manifestation of malnutrition. Calcium (Ca) has been proved to play an important part in maintaining body homeostasis and regulating cellular function. However, there are still a lack of studies on the association between malnutrition and Ca deficiency in IBD. This research aimed to investigate the role of Ca for malnutrition in IBD patients.

METHODS

We prospectively collected blood samples from 149 patients and utilized inductively coupled plasma mass spectrometry to examine their venous serum trace element concentrations. Logistic regression analyses were used to investigate the association between Ca and malnutrition. Receiver operating characteristic (ROC) curves were generated to calculate the cutoffs for determination of Ca deficiency.

RESULTS

Except Ca, the concentrations of the other six trace elements presented no statistical significance between non-malnutrition and malnutrition group. In comparison with the non-malnutrition group, the serum concentration of Ca decreased in the malnutrition group (89.36 vs 87.03 mg/L, p = 0.023). With regard to ROC curve, Ca < 87.21 mg/L showed the best discriminative capability with an area of 0.624 (95% CI: 0.520, 0.727, p = 0.023). Multivariate analyses demonstrated that Ca < 87.21 mg/L (OR = 3.393, 95% CI: 1.524, 7.554, p = 0.003) and age (OR = 0.958, 95% CI: 0.926, 0.990, p = 0.011) were associated with malnutrition risk. Serum Ca levels were significantly lower in the malnutrition group than those in the non-malnutrition group among UC patients, those with severe disease state or the female group.

CONCLUSIONS

In patients with IBD, Ca deficiency is an independent factor for high malnutrition risk.

A novel automated multi-cycle magnetic solid-phase extraction coupled to LC-MS/MS to study the disorders of six functional B vitamins in patients with gastroenterology and hyperhomocysteinemia

B vitamins are essential for human life and their disorders can cause a variety of diseases. Solid-phase extraction (SPE) coupled to LC-MS/MS is a preferred technique for determining multiple B vitamins, however, their complexity in real biological matrices makes it hard to achieve satisfactory recovery and accuracy when simultaneous detection. In this study, a novel automated multi-cycle magnetic SPE (MSPE) coupled to the LC-MS/MS method was established using a mixed-mode anion exchange magnetic adsorbent for the simultaneous extraction of six functional B vitamins, including methylmalonic acid, riboflavin, pantothenic acid, 4-pyridoxic acid, folic acid, and 5-methyltetrahydrofolate. After three consecutive MSPE cycles, the recoveries of all analytes were between 51.5% and 89.6%. The method exhibited excellent sensitivity and linearity, with a dynamic range of 200-fold (R > 0.99 for all analytes), exceptional accuracy (ranging between 95.4% and 105.6%) and precision (with RSDs ≤ 6.2%) without significant matrix effects or interferences. Compared to manual SPE method, the automated multi-cycle MSPE method has better feasibility and greater vitamin coverage. It shows a high correlation with the manual method for the detection of 5-methyltetrahydrofolate and folate (R > 0.99). A study of patients from the gastroenterology department showed that those undergoing surgery and those with malignancies may be at risk of folate deficiency. In addition, patients with hyperhomocystinemia had higher levels of methylmalonic acid and lower levels of 5-methyltetrahydrofolate, which correlated with homocysteine levels (R = 0.404 and -0.311, respectively) and showed dose-response relationships. This method is highly automated and cost-effective, with minimal systematic error, making it suitable for the analysis of clinical samples.

Navigating the Gut-Cardiac Axis: Understanding Cardiovascular Complications in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) presents a complex interplay of chronic inflammation in the gastrointestinal tract and is associated with various extraintestinal manifestations, including cardiovascular complications (CVCs). IBD patients face an elevated risk of CVCs, including coronary artery disease, heart failure, arrhythmias, stroke, peripheral artery disease, venous thromboembolism, and mesenteric ischemia, necessitating comprehensive cardiovascular risk assessment and management. The intricate interplay between chronic inflammation, genetic predisposition, environmental factors, and immune dysregulation likely contributes to the development of CVCs in IBD patients. While the exact mechanisms linking IBD and CVCs remain speculative, potential pathways may involve shared inflammatory pathways, endothelial dysfunction, dysbiosis of the gut microbiome, and traditional cardiovascular risk factors exacerbated by the chronic inflammatory state. Moreover, IBD medications, particularly corticosteroids, may impact cardiovascular health by inducing hypertension, insulin resistance, and dyslipidemia, further amplifying the overall CVC risk. Lifestyle factors such as smoking, obesity, and dietary habits may also exacerbate cardiovascular risks in individuals with IBD. Lifestyle modifications, including smoking cessation, adoption of a heart-healthy diet, regular exercise, and optimization of traditional cardiovascular risk factors, play a fundamental role in mitigating CVC risk. Emerging preventive strategies targeting inflammation modulation and gut microbiome interventions hold promise for future interventions, although further research is warranted to elucidate their efficacy and safety profiles in the context of IBD. Continued interdisciplinary collaboration, advanced research methodologies, and innovative interventions are essential to address the growing burden of CVCs in individuals living with IBD and to improve their long-term cardiovascular outcomes.

Risks of undernutrition and depression in hospitalized patients: A cross-sectional study

Undernutrition in hospitalized patients is a significant healthcare burden worldwide. Depression is a major global health problem characterized by symptoms such as altered mood, loss of interest and pleasure, and impairment in cognitive and physical functions. Patients hospitalized for medical conditions have a higher risk of depression than the general population. The purpose of this study was to explore the relationship between undernutrition risk and depression risk in hospitalized patients. The design of this study was an observational cross-sectional analytic. A questionnaire form created by the investigator including sociodemographic data, dietary patterns, presence of chronic diseases and anthropometric measurements, Nutritional Risk Screening and Patient Health Questionnaire-2 were applied to the patients. All quantitative data were expressed as the median and interquartile range and qualitative data were expressed as numbers and percentage. Mann-Whitney U test and Kruskal-Wallis test were used to analyze nonparametric data; Chi-square and Fisher Exact test were used to analyze qualitative data. P < .05 was considered statistically significant. A total of 308 patients who met the criteria were reached. Undernutrition was detected in 28.6% of the participants, and depression was present in 37.3%. A statistically significant relationship was found between the risk of undernutrition and the risk of depression, with individuals without a risk of depression being found to have a lower risk of undernutrition. (P < .001). The risk of undernutrition was found to increase with advancing age. Moreover, individuals with higher values for arm muscle area, arm muscle circumference, mid-upper arm circumference, triceps skinfold thickness, calf circumference, and body mass index had a lower risk of undernutrition. No relationship was found between gender and the risk of depression. However, a statistically significant relationship was observed between age and the risk of depression, indicating that older patients had a higher risk of depression. In this study, a statistically significant relationship was found between the risk of undernutrition and the risk of depression in hospitalized patients. It was observed that the risk of undernutrition was lower in individuals without risk of depression.

Nutritional Risk and Sarcopenia Features in Patients with Crohn's Disease: Relation to Body Composition, Physical Performance, Nutritional Questionnaires and Biomarkers

Patients with Crohn's disease (CD) face malnutrition risk, which, combined with inflammation, can lead to sarcopenia, associated with a worse prognosis. The purpose of the present study was to assess malnutrition and sarcopenia in patients with CD. Fifty-three patients (26 women) participated (38.1 ± 10.9 years, 79% in remission). Body composition, physical performance, nutritional questionnaires, and biomarkers were performed. Malnutrition was screened with the Mini Nutritional Assessment (MNA) and the Malnutrition Inflammation Risk Tool (MIRT) and was assessed with the Global Leadership Initiative on Malnutrition (GLIM) tool using etiologic along with three different phenotypic criteria: low Body Mass Index (BMI), low Calf Circumference (CC), and low Fat-Free Mass Index (FFMI). To find cases and evaluate sarcopenia, the Sarcopenia Questionnaire (SARC-F) and European Working Group on Sarcopenia2 (EWGSOP2) criteria were used. Malnutrition rates were 11.3% (n = 6), 7.5% (n = 4), and 5.6% (n = 3) based on low FFMI, CC, and BMI, correspondingly. Four (7%) patients had low Hand-Grip Strength (HGS), n = 8 (14.8%) had low Appendicular Lean Mass (ALM), and n = 3 (5.6%) had low gait speed. No-one had sarcopenia. A high albumin and triceps skinfold pattern, identified by principal component analysis, was related to reduced C-Reactive Protein (CRP) levels (B = -0.180, SE = 0.085, p = 0.045). In conclusion, based on the studied anthropometric, nutritional, and functional variables, CD patients were not diagnosed with sarcopenia in the present study. Body composition patterns were related to the inflammatory burden, underlying the interplay of inflammation and malnutrition, even in remission states. Further studies on older populations and during disease exacerbation are necessary to explore the potential link between CD, inflammation, and sarcopenia.

Evaluation of Albumin, Transferrin and Transthyretin in Inflammatory Bowel Disease Patients as Disease Activity and Nutritional Status Biomarkers

Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), is often accompanied by malnutrition that manifests itself as nutrient deficiencies and body mass loss or deficit. The purpose of this study is to evaluate the utility of albumin, transferrin and transthyretin levels in the assessment of nutritional status and IBD activity. The case-control study included 82 IBD patients. The serum concentrations of albumin, transferrin and transthyretine were determined by a quantitative sandwich enzyme-linked immunosorbent assay (ELISA). Significantly lower median concentrations of albumin were found in the IBD patients vs. controls and in CD patients compared to the UC patients. Significantly higher median transthyretin concentrations were found in the IBD patients compared to the healthy subjects. There were no significant differences in median transferrin concentrations between the IBD patients and the healthy subjects. Significantly higher albumin levels were found in IBD patients in remission compared to patients with moderate and severe exacerbation of IBD symptoms. There were no significant differences in the median transferrin or transthyretin levels in patients with IBD depending on disease activity. No differences were identified in the median transferrin or transthyretin levels in the IBD patients according to nutritional status. The median albumin concentrations in the IBD subjects were significantly higher in patients with normal body fat, normal BMI and normal waist circumferences compared to those with an abnormal nutritional status. The albumin levels reflect both nutritional status and disease activity and therefore cannot be considered a prognostic marker of malnutrition in IBD. As regards the utility of transferrin and transthyretin as markers of activity and nutritional status in IBD patients, further studies are required.