Impact of Bariatric Surgery on the Long-term Disease Course of Inflammatory Bowel Disease

Reviewing the impact of obesity on inflammatory bowel disease and considerations for optimizing management

PURPOSE OF REVIEW

This review examines the complex relationship between obesity and inflammatory bowel disease (IBD), encompassing their potentially shared pathogenesis, the impact of obesity on the natural history and treatment outcomes of IBD, and the management of obesity in the patient with IBD.

RECENT FINDINGS

Obesity represents a state of chronic inflammation that may not only contribute to IBD pathogenesis, but also influence disease progression, complications, and response to treatment. Increased visceral adiposity may carry negative prognostic implications for disease and treatment-specific outcomes. Antiobesity medications, endoscopic bariatric therapies, and even bariatric surgery may be effective and well tolerated in selected patients with IBD.

SUMMARY

The intersection of obesity and IBD presents a significant clinical challenge, with obesity influencing the natural history of IBD and potentially affecting treatment efficacy. As obesity prevalence among IBD patients rises, a tailored approach to management is crucial, taking into account the individualized risks and benefits of various treatment strategies, including lifestyle interventions, pharmacotherapy, endoscopic procedures, and bariatric surgery.

Impact of Obesity and Metabolic Syndrome on IBD Outcomes

PURPOSE OF REVIEW

The recent surge in inflammatory bowel disease (IBD) cases has paralleled a significant rise in obesity and metabolic comorbidities rates. In this article, we explore the potential influence of obesity and associated metabolic comorbidities on disease progression, complications, treatment response, surgical outcomes, health economics, and the potential impact of obesity treatment on the course of IBD.

FINDINGS

Contrary to visceral adiposity, obesity does not consistently result in an increased risk of IBD-related complications. Patients with IBD have a higher risk of acute arterial events, likely linked to systemic inflammation. Substantial evidence suggests that obesity has a negative impact on the response to IBD treatment, with this effect being most thoroughly studied in biologics and immunomodulators. The rates of overall complications and post-operative infections are higher in patients who are obese. There are limited but promising data regarding the impact of weight loss techniques, including exercise, medications, and bariatric interventions, on the outcomes in IBD. Both obesity and diabetes have adverse effects on the overall quality of life and place an increased financial burden on the IBD population. A growing body of evidence indicates a connection between obesity and associated metabolic comorbidities and negative outcomes in IBD, yet further efforts are required to fully understand this relationship.

Bariatric surgery in inflammatory bowel disease: a comparative analysis of 450,000 patients

BACKGROUND

Studies were conducted to investigate the outcomes of bariatric surgery (BS) among inflammatory bowel disease (IBD) patients.

OBJECTIVES

We aimed to analyze previous literature, comparing the outcomes of BS between IBD and non-IBD patients.

SETTING

Not applicable.

METHODS

PubMed, Scopus, and Web of Science were searched on 25/9/2023 for comparative studies on outcomes of BS in IBD patients. RevMan Software v5.4 was used to conduct the analysis.

RESULTS

Our analysis revealed an insignificant difference in the change of body mass index (BMI) at 1-year post-BS between IBD and non-IBD patients. IBD patients had a higher risk of acute renal failure, hemorrhage, and readmission following BS (RR: 2.16, 95% CI: 1.55-3, RR: 1.57, 95% CI: 1.22-2.04, RR: 1.56, 95% CI: 1.17-2.08, respectively). No significant difference was observed between both groups regarding wounds, leak/intra-abdominal infection, thromboembolic complications, and bowel obstruction. A higher incidence of postoperative complications was seen among IBD patients undergoing RYGB compared with SG (RR: 2.21, 95% CI: 1.43-3.41). There was a significant decline in steroid use following BS in IBD patients (RR: .67, 95% CI: .53-.84). Comparison between UC and Crohn's disease (CD) revealed insignificant differences in treatment escalation or de-escalation. Both IBD and non-IBD patients had similar lengths of hospitalization.

CONCLUSIONS

BS is equally effective in IBD and non-IBD patients in terms of weight loss at 1-year follow-up. Nevertheless, IBD patients are at a higher risk of postoperative complications, micronutrient deficiency, and readmission. Both UC and CD reported a decline in steroid use following surgery without a preferential advantage to a particular IBD sub-type.

Effect of Bariatric Surgery on Disease Outcomes in Patients With Inflammatory Bowel Disease: A US-based Propensity Matched Cohort Study

INTRODUCTION AND AIM

A growing body of evidence suggests a negative impact of obesity on the disease activity of inflammatory bowel disease (IBD). The primary aim of the study was to evaluate disease outcomes of IBD in patients after bariatric surgery (BS).

METHODS

Patients with IBD and morbid obesity who underwent BS were compared with patients with IBD and morbid obesity without BS in a retrospective, propensity-score matched cohort study using TriNetX, a multi-institutional database. The primary aim was to assess the 2-year risk of a composite of disease-related complications, which included intravenous steroid use or IBD-related surgery. Risk was expressed as adjusted odds ratios (aOR) with 95% confidence intervals (CI).

RESULTS

In all, 482 patients (3.4%) with IBD and morbid obesity underwent BS (mean age 46.9±11.2 y old, mean BMI 42.1±7.72 kg/m 2 , Crohn's disease 60%). After propensity-score matching, the BS cohort had a lower risk (aOR 0.31, 95% CI 0.17-0.56) of a composite of IBD-related complications compared with the control cohort. After propensity-score matching, the BS cohort with sleeve gastrectomy had a decreased risk (aOR 0.45, 95% CI 0.31-0.66) of a composite of IBD-related complications. There was no difference in the risk (aOR 0.77, 95% CI 0.45-1.31) of a composite of IBD-related complications between the BS cohort with Roux-en-Y gastric bypass (RYGB) compared with the control cohort.

CONCLUSION

Sleeve gastrectomy but not Roux-en-Y gastric bypass is associated with improved disease-specific outcomes in patients with IBD and morbid obesity.

Effectiveness and Safety of Semaglutide for Weight Loss in Patients With Inflammatory Bowel Disease and Obesity

BACKGROUND

Semaglutide, a glucagon-like peptide-1 receptor agonist, has shown sustained and clinically significant weight loss in the general population. There are limited data on outcomes of its use in patients with inflammatory bowel disease (IBD).

METHODS

A retrospective cohort study was conducted between June 4, 2021, and December 11, 2023, using TriNetX, a U.S. multi-institutional database in patients with obesity who had IBD compared with patients without IBD. The primary aim was to assess the mean total body weight (TBW) change between 6 and 15 months from initiation of semaglutide compared with baseline between the 2 cohorts. One-to-one (1:1) propensity score matching was performed for demographics, comorbid conditions, smoking status, and mean body mass index. A 2-sample t test was performed to assess mean TBW change from baseline, with a P value <.05 considered to be statistically significant. We also compared the risk of IBD-specific outcomes with and without semaglutide use in patients with IBD.

RESULTS

Out of 47 424 patients with IBD and obesity, 150 (0.3%) patients were prescribed semaglutide (mean age 47.4 ± 12.2 years; mean TBW 237 ± 54.8 pounds; mean body mass index 36.9 ± 6.5 kg/m2; 66% Crohn's disease). There was no difference in mean TBW change after initiation of semaglutide in the IBD and non-IBD cohorts (-16 ± 13.4 pounds vs -18 ± 12.7 pounds; P = .24). There was no difference in mean TBW change between 6 and 12 months (-16 ± 13 pounds vs -15 ± 11.2 pounds; P = .24) and 12 and 15 months (-20 ± 13.2 pounds vs -21 ± 15.3 pounds; P = .49) between the 2 cohorts. There was no difference in the risk of oral or intravenous steroid use and any-cause hospitalization in the semaglutide group compared with the group without semaglutide use in patients with IBD.

CONCLUSION

Semaglutide use is effective in patients with IBD and obesity similar to patients without IBD, with >5% mean weight loss. There was no increased risk of IBD-specific adverse events with semaglutide use.

Bariatric Surgery Outcomes in Patients with Inflammatory Bowel Disease in the United States: An Analysis of the Nationwide Readmissions Database

PURPOSE

Bariatric surgery has been reported to produce durable weight loss in the management of obesity; sleeve gastrectomy (SG) is the most common bariatric procedure. Obesity is a common comorbidity of inflammatory bowel disease (IBD), and the impact of IBD on short-term SG outcomes has not been widely reported. This study assessed whether IBD was associated with adverse post-SG outcomes.

MATERIALS AND METHODS

Hospitalizations of patients undergoing SG in the United States were identified using the 2010-2020 Nationwide Readmissions Database (NRD) and stratified by IBD diagnosis. The SG cohort was propensity-matched based on age, biological sex, body mass index (BMI), comorbid diabetes, hypertension, depression, chronic obstructive pulmonary disease, and discharge in quarter four. Primary aims were to compare in-hospital mortality, post-operative complications, and all-cause 90-day readmission between patients with and without IBD. Secondary outcomes were length of stay (LOS) and total hospital cost.

RESULTS

A total of 2030 hospitalizations were matched. The odds of complication were 48% higher for hospitalizations of patients with IBD (11.1% vs. 7.8%; aOR 1.48, aOR 95% CI 1.10-2.00, p = .009). The most common complication was nausea (4.9% vs. 3.7%, p = .187). No statistically significant difference was observed for all-cause 90-day readmissions, LOS, or hospital cost.

CONCLUSION

Hospitalizations of patients with IBD who underwent SG experienced significantly higher post-operative complication rates. However, the similar lengths of stay and readmission rates compared to propensity-matched SG hospitalizations without IBD suggest many complications were minor. SG remains a safe weight loss procedure for patients suffering from IBD and obesity.

Short-term outcomes of bariatric surgery in patients with inflammatory bowel disease: a national analysis

BACKGROUND

While considered standard of care for obesity management, bariatric surgery is uncommon in patients with co-morbid inflammatory bowel disease (IBD).

OBJECTIVES

The present study aimed to assess the association of IBD with postoperative outcomes and resource use following bariatric surgery.

SETTING

Academic, university-affiliated; United States.

METHODS

All elective adult hospitalizations for laparoscopic sleeve gastrectomy or Roux-en-Y gastric bypass (RYGB) were identified in the 2016-2019 Nationwide Readmissions Database. Patients were classified based on diagnosis of ulcerative colitis (UC) or Crohn's disease (CD). Multivariable regression models were developed to evaluate the association of IBD with outcomes of interest.

RESULTS

Of an estimated 719,270 eligible patients, 860 and 1214 comprised the UC and CD cohorts, respectively. Compared to non-IBD, UC and CD had a higher Elixhauser comorbidity index (UC: 3.0 ± 1.4; CD: 3.1 ± 1.5; non-IBD: 2.7 ± 1.4, P < .001) and more frequently underwent sleeve gastrectomy (UC: 77.5%; CD: 83.2%; non-IBD: 68.8%, P < .001). All IBD patients survived to discharge. After adjustment, IBD was not associated with significant differences in most clinical outcomes analyzed. UC (adjusted odds ratio: 2.86; 95% confidence interval: 1.14-7.13) and CD (adjusted odds ratio: 4.40; 95% confidence interval: 2.20-8.80) were associated with increased odds of gastric outlet obstruction after RYGB but not sleeve gastrectomy. CD, but not UC, was linked to significantly higher odds of small bowel obstruction following RYGB (adjusted odds ratio: 4.50; 95% confidence interval: 1.76-11.49). There was no difference in index LOS, hospitalization costs, or odds of 30-day readmission based on IBD.

CONCLUSIONS

Patients with obesity and IBD faced low rates of adverse outcomes following bariatric surgery. There is an increased risk of gastrointestinal obstruction for patients with IBD undergoing RYGB. Given its safety profile, bariatric surgery can be utilized as a weight loss intervention for the growing proportion of patients with obesity and co-morbid IBD.

Recommendations on the management of severe obesity in patients with inflammatory bowel disease of the Spanish Group on Crohn's Disease and Ulcerative Colitis (GETECCU), Spanish Society of Obesity (SEEDO), Spanish Association of Surgery (AEC) and Spanish Society of Digestive Endoscopy (SEED)

Obesity is a multifactorial, chronic, progressive and recurrent disease considered a public health issue worldwide and an important determinant of disability and death. In Spain, its current prevalence in the adult population is about 24% and an estimated prevalence in 2035 of 37%. Obesity increases the probability of several diseases linked to higher mortality such as diabetes, cardiovascular disease, hyperlipidemia, arterial hypertension, non-alcoholic fatty liver disease, several types of cancer, or obstructive sleep apnea. On the other hand, although the incidence of inflammatory bowel disease (IBD) is stabilizing in Western countries, its prevalence already exceeds 0.3%. Paralleling to general population, the current prevalence of obesity in adult patients with IBD is estimated at 15-40%. Obesity in patients with IBD could entail, in addition to its already known impact on disability and mortality, a worse evolution of the IBD itself and a worse response to treatments. The aim of this document, performed in collaboration by four scientific societies involved in the clinical care of severe obesity and IBD, is to establish clear and concise recommendations on the therapeutic possibilities of severe or typeIII obesity in patients with IBD. The document establishes general recommendations on dietary, pharmacological, endoscopic, and surgical treatment of severe obesity in patients with IBD, as well as pre- and post-treatment evaluation.

Results of the national registry of patients diagnosed with inflammatory bowel disease candidates for bariatric surgery (ReNacEIBar)

BACKGROUND

Our aim is to carry out a national registry of patients with inflammatory bowel disease (IBD) who underwent bariatric surgery, as well as evaluate the results and management of this type of patients in the usual clinical practice.

METHODS

National multicentric observational retrospective study, including patients, previously diagnosed with IBD who underwent bariatric surgery from January 2000 to December 2022.

RESULTS

Forty-one patients have been included: 43,9% previously diagnosed with ulcerative colitis, 57,3% Crohn's disease, and an indeterminate colitis (2,4%). The preoperative BMI was 45.8 ± 6,1 kg/m2. Among the bariatric surgeries, 31 (75,6%) sleeve gastrectomy, 1 (2,4%) gastric bypass and 9 (22%) one anastomosis gastric have been carried out. During the postoperative period, 9.8% complications have been recorded. BMI was 29,5 ± 4,7 kg/m2 and percent total weight lost was 33,9 ± 9,1% at 12 months.

CONCLUSIONS

Bariatric surgery in patients with inflammatory bowel disease can be considered safe and effective.

Systematic review: Outcomes of bariatric surgery in patients with inflammatory bowel disease and de-novo IBD development after bariatric surgery

A large proportion of patients diagnosed with inflammatory bowel disease are obese. Outcomes of bariatric surgery in patients with IBD and on IBD disease course itself is not clear. Furthermore, there is some evidence that bariatric surgery can precipitate the development of de-novo IBD. Thus, the aim of this systematic review was to summarise the evidence from the literature surrounding these questions. A comprehensive literature review was conducted based on the preferred reporting items for systematic reviews and meta-analysis guidelines (PRISMA). PUBMED, and MEDLINE databases was searched using a combination of keywords and MeSH terms including "gastric bypass", "sleeve gastrectomy", "Roux-en-Y", "Duodenal switch", "RYGB", "bariatric surgery" and "inflammatory bowel disease", "Crohn's disease" ,"Ulcerative colitis". Studies published up to March 2020 were included in this analysis. 22 studies met the inclusion criteria. Studies revealed that bariatric surgery is safe and effective for patients with IBD and resulted in significant weight loss at both the 6-month and 12-month time points. Furthermore, multiple studies reported de-novo IBD development following bariatric surgery in a selection of patients.

Obesity and novel management of inflammatory bowel disease

Obesity is prevalent within the inflammatory bowel disease (IBD) population, particularly in newly developed countries. Several epidemiological studies have suggested that 15%-40% of IBD patients are obese, and there is a potential role of obesity in the pathogenesis of IBD. The dysfunction of mesenteric fat worsens the inflammatory course of Crohn’s disease and may induce formation of strictures or fistulas. Furthermore, obesity may affect the disease course or treatment response of IBD. Given the increasing data supporting the pathophysiologic and epidemiologic relationship between obesity and IBD, obesity control is being suggested as a novel management for IBD. Therefore, this review aimed to describe the influence of obesity on the outcomes of IBD treatment and to present the current status of pharmacologic or surgical anti-obesity treatments in IBD patients.

Outcomes of bariatric surgery in patients with inflammatory bowel disease from a French nationwide database

BACKGROUND

The outcomes of bariatric surgery (BS) in patients with chronic inflammatory bowel disease (IBD) remain rarely described. We aimed to evaluate the 90-day morbidity and mortality rates, and the risk of IBD complications 2 years after BS.

METHOD

Patients from the French Programme de Médicalisation des Systèmes d'Information (PMSI) database who underwent a primary BS between 2016 and 2018 were included. We identified patients with a previous diagnosis of IBD. Postoperative 90-day (POD90) morbidity and mortality rates were compared between the two groups. The evolution of IBD was followed 2 years after BS.

RESULTS

Between 2016 and 2018, 138 980 patients underwent primary BS, including 587 patients with IBD: 326 (55.5 per cent) with Crohn's disease (CD) and 261 (44.5 per cent) with ulcerative colitis (UC). The preferred surgical technique was sleeve gastrectomy, especially in the IBD group (81.1 per cent), followed by gastric bypass (14.6 per cent). Patients with IBD had more comorbidities (Charlson Comorbidity Index of 1 or more, hypertension, and diabetes; P < 0.001) than those without IBD. The POD90 mortality rate did not differ between the two groups (0.049 per cent in the IBD group versus 0 per cent in the non-IBD group), but more unscheduled rehospitalizations at POD90 were observed in patients with IBD (6.0 per cent versus 3.7 per cent; P = 0.004). Two years after BS, 86 patients (14.6 per cent) in the IBD group had at least one unplanned readmission for the management of their IBD; 15 patients stayed for 3 or more days. After multivariable analysis, patients with CD had an independent elevated risk of IBD-related unplanned readmissions 2 years after BS versus UC (adjusted odds ratio 1.90, 95 per cent c.i. 1.22 to 2.97; P = 0.005).

CONCLUSION

In a highly selected cohort of patients with well-controlled IBD, BS did not result in added mortality or morbidity. A point of vigilance must be underlined regarding BS in patients with CD.

Bariatric Surgery in Patients With Inflammatory Bowel Disease: A Case-Control Study from the GETAID

BACKGROUND

The prevalence of obesity and the number of bariatric surgeries in both the general population and in patients with inflammatory bowel disease (IBD) have increased significantly in recent years. Due to small sample sizes and the lack of adequate controls, no definite conclusions can be drawn from the available studies on the safety and efficacy of bariatric surgery (BS) in patients with IBD. Our aim was to assess safety, weight loss, and deficiencies in patients with IBD and obesity who underwent BS and compare findings to a control group.

METHODS

Patients with IBD and a history of BS were retrospectively recruited to centers belonging to the Groupe d'Etude Thérapeutique des Affections Inflammatoires du Tube Digestif (GETAID). Patients were matched 1:2 for age, sex, body mass index (BMI), hospital of surgery, and type of BS with non-IBD patients who underwent BS. Complications, rehospitalizations, weight, and deficiencies after BS were collected in cases and controls.

RESULTS

We included 88 procedures in 85 patients (64 Crohn's disease, 20 ulcerative colitis, 1 unclassified IBD) with a mean BMI of 41.6 ± 5.9 kg/m2. Bariatric surgery included Roux-en-Y gastric bypass (n = 3), sleeve gastrectomy (n = 73), and gastric banding (n = 12). Eight (9%) complications were reported, including 4 (5%) requiring surgery. At a mean follow-up of 34 months, mean weight was 88.6 ± 22.4 kg. No difference was observed between cases and controls for postoperative complications (P = .31), proportion of weight loss (P = .27), or postoperative deficiencies (P = .99).

CONCLUSIONS

Bariatric surgery is a safe and effective procedure in patients with IBD and obesity; outcomes in this patient group were similar to those observed in a control population.

Exploring the Relationship Between Bariatric Surgery and Inflammatory Bowel Disease: A Systematic Review

Background

Obesity affects over 40% of Americans. Bariatric surgery is an increasingly popular and well-studied method to achieve weight loss, improve metabolic homeostasis, and resolve obesity-related comorbid conditions. While the impact of bariatric surgery on weight loss and metabolic health has been extensively studied, there is an increasing body of literature characterizing the impact of bariatric surgery on gastrointestinal health and inflammation. Inflammatory bowel disease (IBD) leads to inflammation in both the small and large intestine, and leads to significant patient morbidity. Similar to obesity, the incidence of IBD is also rising. Patients with IBD and obesity may seek bariatric surgery. The impact of bariatric surgery on IBD is not well understood, but critical to understand for optimal patient care. Herein, we review the currently available literature on the impact of bariatric surgery on IBD including common trends, discrepancies in findings, and remaining knowledge gaps in need of further study.

Methods

A systematic review of the PubMed/MEDLINE database using PRISMA guidelines was performed.

Results

We identified 12 manuscripts discussing de novo IBD after bariatric surgery and 16 studying bariatric surgery in patients with pre-existing IBD. Overall, bariatric surgery appears to be safe in patients with pre-existing IBD but may increase the risk of developing de novo IBD.

Conclusions

Further research into optimal surgical approaches, patient selection, and mechanisms on how bariatric surgery impacts IBD is needed.

Impact of Obesity on Inflammatory Bowel Disease

PURPOSE OF REVIEW

This review highlights recent work that evaluates the impact of obesity on inflammatory bowel disease (IBD) pathogenesis and management.

RECENT FINDINGS

The impact of obesity on IBD prevalence, clinical course, and management, has been studied and described more so in recent years. Studies have shown that obesity increases IBD disease activity, leads to longer hospitalization courses, and increases the likelihood of the development of extraintestinal manifestations. Recent evidence has also suggested that obese IBD patients have a higher frequency of extended steroid treatment and increased use of antibiotics compared to non-obese IBD patients. The effect of obesity on patients with IBD is a topic that has garnered widespread interest in the last decade due to the increasing prevalence of both diseases. To date however, although there are still many unanswered questions. It is quite clear that obesity, and more specifically, visceral adiposity, affects numerous IBD-related outcomes in regard to pathogenesis, extra-intestinal manifestations, response to medical and surgical therapies, hospital length of stay, healthcare-related costs, and health-related quality of life. Future studies should include larger patient populations and evaluate additional factors that are altered in those with obesity including the gut microbiome, dietary patterns, and whether weight loss and/or degree of weight loss impact clinical outcomes.

Visceral adiposity and inflammatory bowel disease

BACKGROUND

Rates of obesity are increasing worldwide, as is the incidence of inflammatory bowel disease (IBD). Obesity is now considered an inflammatory state. Visceral adiposity in particular may be associated with a more severe inflammatory phenotype in IBD.

AIM

The aim of this review article is to summarise the current literature on the association between visceral adiposity and outcomes in inflammatory bowel disease METHODS: To collect relevant articles, PubMed/MEDLINE and Embase searches were performed using Boolean search phrases. Grey literature and manual searches were also performed. Abstracts were selected by two independent reviewers based on pre-determined criteria. Full text articles were reviewed, and data extracted and assessed.

RESULTS

One hundred twenty-seven abstracts were obtained through the initial search, with 85 abstracts reviewed and 22 full text articles included. Characteristics are included in Table 1. Most of these were retrospective studies and of moderate or weak quality. Studies suggested visceral fat content is higher in Crohn's disease than in healthy controls. Visceral adiposity was associated with an increased risk of complex Crohn's disease phenotype (OR 26.1 95% CI 2-75.4; p = 0.02). Post-operative recurrence was higher in patients with higher visceral fat indices (RR 2.1; CI 1.5-3; p = 0.012). There were conflicting data regarding the effect of visceral adiposity on post-operative complications and the efficacy of medical therapy. Table 1 Study characteristics Author Year Country Study type Study numbers Control group Disease type Methodology e.g. CT Body composition measurements Results Argeny [24] 2018 Austria Retrospective cohort N = 95 N/A Crohn's disease CT; L3 level Visceral fat area (cm²) Visceral fat index (VFA/m²) No association between VFA or VFI and short-term post-operative outcomes Bryant [30] 2018 Australia Prospective cohort N = 110 N/A Crohn's disease and UC DXA Visceral adipose tissue (VAT) (cm³) Visceral adipose tissue (grams) VAT/height index (cm³/m²) VAT:subcutaneous adipose tissue ratio Fat mass index (kg/m²) VAT and VHI increased significantly over 24 months Bryant [13] 2018 Australia Prospective cohort N = 72 N/A Crohn's disease; female DXA Visceral adipose tissue (VAT) (cm³) Visceral adipose tissue (grams) VAT/height index (cm³/m²) VAT:subcutaneous adipose tissue ratio VAT:SAT positively associated with stricturing disease Adiposity not associated with fistulising disease phenotype VAT:SAT significantly associated with faecal calprotectin in L3 phenotype VAT:SAT significantly negatively associated with VHI and QoL over 24 months Buning [25] 2015 Germany Case control N = 50 N = 19 healthy controls Crohn's disease MRI US VAT Thickness of abdominal fat Distance to posterior wall of aorta Area of inferior part of perirenal fat VAT accumulation was higher in CD patients vs healthy controls VAT and VAT/fat mass ratio higher in patients in short-term remission vs long-term remission VAT/FM higher in stricturing/fistulising disease vs inflammatory subtype No association between VAT/FM and CDAI, HBI or anti-TNF treatment Connolly [26] 2014 US Retrospective cohort N = 143 N/A Crohn's disease CT (L1-L5 level) Visceral/intra-abdominal adiposity (VA) Subcutaneous adiposity (SA) VA not associated with post-operative morbidity Decreased SA and increased visceral/subcutaneous ratio were predictive of post-op complications. (p = 0.02; p < 0.001) Cravo [27] 2017 Portugal Retrospective cohort N = 71 N/A Crohn's disease CT (L3 level) Smooth muscle area (cm²) Visceral fat area (cm²) Subcutaneous fat area (cm²) Visceral fat index Muscle radiation attenuation L2 phenotype associated with lower muscle attenuation and higher visceral fat index (non-significant) B2/B3/surgery - significantly lower muscle attenuation. VFI associated with increased risk of complicated phenotype. (OR 26.1; 95% CI 1-75; p = 0.02) Ding [17] 2016 US Retrospective cohort N = 164 N/A Crohn's disease CT (L3 level) Visceral fat area (cm²) Subcutaneous fat area Total fat area Visceral obesity associated with longer duration of surgery, increased intra-operative blood loss and longer length of bowel resected Higher complication rates in patients with visceral obesity (p < 0.001) VFA independent risk factor of adverse post-op outcomes Ding [14] 2017 Retrospective cohort N = 106 N/A Crohn's disease CT (L3 level) Visceral fat area Subcutaneous fat area Skeletal muscle area Skeletal muscle index Visceral obesity and myopenic obesity not significantly associated with risk of primary non-response Body composition factors not associated with secondary loss of response Erhayiem [18] 2011 UK Retrospective cohort N = 50 N/A Crohn's disease CT (L4 level) Mesenteric fat index (visceral:subcutaneous area ratio)N = 50 Mesenteric fat index was significantly higher in complicated Crohn's disease. ROC analysis for MFI in identifying complicated Crohn's disease: AUC = 0.95 (95% CI 0.89-1.0) Feng [28] 2018 China Retrospective cohort N = 80 Non-IBD GI patients Crohn's disease CT-energy spectral Visceral fat area (cm²) Subcutaneous fat area (cm²) Mesenteric fat index No significant difference in VFA between Crohn's disease cohort and control group. (p = 0.669). ROC analysis: detection of disease based on VFA and MFI: AUC 0.776 Sensitivity 77.5% Specificity 67.5% Hafraoui [16] 1998 France/Belgium Prospective N = 43 Healthy volunteers n = 13 Intestinal resection n = 9 Crohn's disease MRI (umbilicus) Total abdominal fat (cm²) Intra-abdominal fat (cm²) Subcutaneous fat (cm²) Ratio of intra-abdominal:total fat area was significantly higher in patients with Crohn's vs controls. (p = 0.012) No correlation between abdominal fat tissue and disease activity, duration or steroid therapy Holt [29] 2017 Australia/New Zealand RCT N = 44 N = 11 placebo group Crohn's disease CT/MRI (L3, L4-5 levels) Visceral adipose tissue area Subcutaneous adipose tissue area Skeletal muscle area Visceral adipose tissue/height index VHI > 1.5 times gender mean was specific for endoscopic recurrence (100%) with sensitivity of 29%. PPV = 1 (0.59-1.00) There was no significant difference in disease activity at 18 months post-resection based on VHI > 1.5 gender mean Li [31] 2015 China Retrospective cohort N = 72 N/A Crohn's disease CT (umbilicus) Visceral fat area (cm²) Subcutaneous fat area (cm²) Mesenteric fat index Post-op recurrence was more frequent with high VFA values. (p = 0.019) VFA and MFI were independent risk factors for post-operative recurrence. (p = 0.013 and p = 0.028, respectively) High VFA and high MFI were significantly higher in patients with endoscopic activity (p = 0.023) Liu [32] 2016 Retrospective case-control N = 59 N = 30 (< 15% increase VFA) IBD with IPAA CT (L3) Visceral fat area Subcutaneous fat area No difference in pouchitis, pouch sinus formation and composite adverse pouch outcomes between the 2 groups with and without VFA increase > 15%. Excessive VAT gain was an independent risk factor for the composite adverse pouch outcomes. (OR 12.6 (95% CI 1.19-133.5) Magro [33] 2018 Brazil Cross-sectional study N = 78 N = 28 Health control Crohn's disease DEXA Fat and lean masses Visceral fat (kg) Visceral fat/BMI Visceral fat per %body fat VF was higher in Crohn's disease group (p = 0.004) compared to controls Parmentier-Decrucq [34] 2009 Prospective study N = 132 N/A Crohn's disease MRI Subcutaneous fat Visceral fat Total abdominal fat increased 18% in Crohn's disease patients treated with infliximab induction therapy Shen [35] 2018 China Retrospective N = 97 N/A Crohn's disease CT (umbilicus) Subcutaneous fat area Visceral fat area Mesenteric fat index VFA and MFI were significantly lower in patients with mucosal healing (post-infliximab). (p < 0.0001) SFA was not significantly different VFA correlated with CDAI (p < 0.001) and was an independent predictive factor for mucosal healing Stidham [15] 2015 Retrospective N = 269 N/A Crohn's disease CT(T10-L5) Subcutaneous fat volume Visceral fat volume No significant difference in visceral fat volume between patients with surgical complications Thiberge [36] 2018 France Retrospective N = 149 N/A Crohn's disease CT (L3 level) Skeletal muscle index Visceral adiposity index Subcutaneous adiposity index SAI and VAI were significantly lower in patients who underwent surgery or who died in 6 months post-CT(p = 0.009 and p < 0.001) VanDerSloot [37] 2017 Cohort study N/A Crohn's disease CT (T11-S5) Visceral adipose tissue volume Non-significant trend toward increased risk of surgery and penetrating disease with increasing VAT Wei [38] 2018 China Retrospective N = 86 N/A IBD post-resection CT (L3 level) Visceral adipose volume Subcutaneous adipose volume Increased visceral:subcutaneous fat ratio was associated with increased procalcitonin levels on post-op days 1, 3 and 5 Yadav [39] 2017 India Prospective N = 97 N/A IBD CT (L4 level) Visceral fat area Subcutaneous fat area No statistically significant correlation between visceral fat and disease behaviour in Crohn's disease N/A not applicable, VFA visceral fat area, VFI visceral fat index, VAT visceral adipose tissue, VHI visceral adipose tissue to height index, SAT subcutaneous adipose tissue, DXA dual-energy X-ray absorptiometry, CT computer tomography, MRI magnetic resonance imaging, US ultrasound, CDAI Crohn's disease activity index, HBI Harvey-Bradshaw Index, anti-TNF anti-tumour necrosis factor, SA subcutaneous adiposity, ROC receiver operating curve, AUC area under the curve, MFI mesenteric fat index, SAI subcutaneous adiposity index, PPV positive predictive value CONCLUSION: Visceral adiposity appears to be increased in Crohn's disease with some evidence that it is also associated with more complex disease phenotypes. There is also a signal that post-operative recurrence rates are affected by increasing mesenteric adiposity. There is a relative lack of data in UC patients and further high-quality studies are necessary to elucidate the relationship between visceral adiposity and IBD and the implications for patient outcomes.

Diet in Intestinal Fibrosis: A Double-Edged Sword

The natural history of inflammatory bowel diseases, especially Crohn’s disease, is frequently complicated by intestinal fibrosis. Because of the lack of effective treatments for intestinal fibrosis, there is an urgent need to develop new therapies. Factors promoting intestinal fibrosis are currently unclear, but diet is a potential culprit. Diet may influence predisposition to develop intestinal fibrosis or alter its natural history by modification of both the host immune response and intestinal microbial composition. Few studies have documented the effects of dietary factors in modulating IBD-induced intestinal fibrosis. As the mechanisms behind fibrogenesis in the gut are believed to be broadly similar to those from extra-intestinal organs, it may be relevant to investigate which dietary components can inhibit or promote fibrosis factors such as myofibroblasts progenitor activation in other fibrotic diseases.

Obesity in inflammatory bowel disease: A review of its role in the pathogenesis, natural history, and treatment of IBD

In contrast to previous perceptions that inflammatory bowel disease (IBD) patients are generally malnourished and underweight, there is mounting evidence to suggest that rates of obesity in IBD now mirror that of the general population. IBD is an immune-mediated condition that appears to develop in individuals who have not only a genetic predisposition to immune dysregulation but also likely exposure to various environmental factors which further potentiate this risk. With the surge in obesity alongside the rising incidence of IBD, particularly in developing nations, the role that obesity may play, not only in the pathogenesis but also in the natural history of disease has become a topic of growing interest. Currently available data exploring obesity's impact on the natural history of IBD are largely conflicting, potentially limited by the use of body mass index as a surrogate measure of obesity at varying time points throughout the disease course. While there are pharmacokinetic data to suggest possible detrimental effects that obesity may have on the response to medical therapy, results in this realm are also inconsistent. Moreover, not only is it unclear whether weight loss improves IBD outcomes, little is known about the safety and efficacy of available weight-loss strategies in this population. For these reasons, it becomes increasingly important to further understand the nature of any interaction between obesity and IBD.

Safety of bariatric surgery in patients with inflammatory bowel disease: A systematic review and meta-analysis

The efficacy of bariatric surgery in achieving weight loss and preventing long-term comorbidities such as cardiovascular diseases, diabetes mellitus and osteoarthritis is well established. Data regarding safety of bariatric surgery in patients with inflammatory bowel disease (IBD) is scarce. We attempted a systematic review and meta-analysis to evaluate the complications following bariatric surgery in patients with IBD. The primary outcomes evaluated were wound infection, Clavien-Dindo grade > II complications and IBD exacerbation (within 1 year). Secondary outcomes evaluated included overall mortality, stricture, small bowel obstruction, acute kidney injury (AKI) and thromboembolism. Pooled outcomes (event rate) with 95% confidence interval (CI) were calculated using random effects model. A total of 14 studies (all observational) with 2608 patients were included. The rates of primary outcomes were: wound infection (4.1%, 95% CI: 0.9-7.2), Clavien-Dindo grade > II complications (2.0%, 95%: CI 0.6-3.5) and IBD exacerbation (4.3%, 95% CI: 0.7-7.9). The pooled rate for other outcomes was: mortality 0.1%, stricture 6.5%, small bowel obstruction 6.7%, AKI 2.2% and thromboembolism 0.1%. Bariatric surgery is relatively safe in patients with IBD and should be pursued to reduce comorbidities associated with obesity. Future comparative studies are needed to further assess the safety of bariatric surgery in population with and without IBD.

Impact of Obesity on the Management of Inflammatory Bowel Disease

The worldwide prevalence of obesity has reached staggering proportions, and the inflammatory bowel disease (IBD) population has not been immune to this trend, with obesity rates estimated to be between 15% and 40%. With the concurrent rise in incidence of IBD itself, there are biologically plausible mechanisms that suggest a potential role of obesity in the pathogenesis of IBD, although epidemiologic data on this issue are conflicting. Similarly, studies exploring the impact that obesity may have on the natural history of disease have produced inconsistent results. Some studies suggest higher and others lower rates of surgery in obese Crohn's disease patients, other studies suggest a higher risk of surgery in obese ulcerative colitis patients, and yet other studies reveal no difference in outcomes regarding hospitalization or surgery for either group. Regardless of its impact on the pathogenesis or natural history of IBD, the rising prevalence of obesity in this population results in a need to better understand the effect it has on IBD management. Although pharmacologic data suggest that obesity may influence the absorption, distribution, and clearance of the available therapeutic agents, the actual clinical consequences that these differences have on disease management are less clear. Finally, it is possible that weight loss interventions for obesity could have an impact on the clinical course of IBD.