Visceral adiposity predicts post-operative Crohn's disease recurrence

A systematic review and meta-analysis of prospective studies on obesity and risk of inflammatory bowel disease

CONTEXT

There are only a few systematic reviews on the association of obesity with risk of inflammatory bowel disease (IBD) to date.

OBJECTIVE

The current study was undertaken to systematically review prospective cohort studies on the association between body mass index (BMI) and risk of IBD. It was carried out according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

DATA SOURCES

Relevant prospective cohort studies published from 1969 to July 2020 were searched through PubMed, MEDLINE, SCOPUS, EMBASE, and Google Scholar, using suitable keywords.

DATA EXTRACTION

Hazard ratios (HRs) or relative risks (RRs) and 95% confidence intervals (CIs) for IBD or its subtypes across categories of BMI were extracted.

DATA ANALYSIS

The log HRs/RRs, including standard errors, were calculated based on reported HRs or RRs and their 95% CIs, and overall effect size was calculated using a fixed-effects model. All statistical analyses were done using STATA version 14.0 (Stata Corp LP, College Station, TX, USA).

CONCLUSION

Overall, 9 studies were included. Combining findings from 5 studies, a statistically significant 21% lower risk of ulcerative colitis incidence was found in patients with obesity than in those with normal weight (RR, 0.79; 95% CI, 0.68-0.92; I2= 0.0%), but not with risk of ulcerative colitis exacerbation, as found by meta-analysis of 3 studies. Pooling data from 5 studies, no significant differences were seen in the risk of Crohn's disease incidence between patients in the highest range of BMI and those in the normal range. In addition, no significant nonlinear association was found between BMI and risk of Crohn's disease (P=0.94). A significant inverse association was found between obesity and total IBD incidence (RR, 0.76; 95% CI, 0.66-0.88; I2=93.2%), but not between increasing BMI and IBD exacerbation, or between increasing BMI and IBD incidence.

Sarcopenia assessed by computed tomography is associated with colectomy in patients with acute severe ulcerative colitis

BACKGROUND

Altered body composition is an important characteristic of malnutrition that may better reflect the clinical course. This study aimed to evaluate the prognostic role of sarcopenia by computed tomography (CT) on colectomy in acute severe ulcerative colitis (ASUC) during index hospitalization and follow-up.

METHODS

254 ASUC patients undergoing CT scans at admission were retrospectively included. Sarcopenia was assessed by the skeletal muscle index (SMI) with CT scans at L3, and patients with an SMI below the lowest sex-specific quartile were diagnosed with sarcopenia. Body mass index (BMI) < 18.5 kg/m² was defined as clinical malnutrition. Univariate and multivariate analyses were performed to determine the association between sarcopenia and colectomy.

RESULTS

The prevalence of sarcopenia in ASUC was 50.0%, and malnutrition was 25.2%. Among sarcopenic patients, 36.2% was malnutrition, 51.2% had normal BMI, 11.8% was overweight, and 0.8% was obese. During index hospitalization, 66.9% patients needed rescue therapy with 52.4% received medical rescue therapy and 14.6% received colectomy. During follow-up, 33.2% patients needed colectomy. Significantly more sarcopenic patients required colectomy (22.0% vs 7.1%, p = 0.001) and rescue therapy (81.9% vs 52.0%, p < 0.001) during index hospitalization and colectomy during follow-up (44.4% vs 23.7%, p = 0.001) than non-sarcopenic patients. However, BMI < 18.5 kg/m² was not related to the clinical course. In multivariate analyses, sarcopenia remained an independent risk factor for rescue therapy and colectomy during index hospitalization and colectomy during follow-up.

CONCLUSION

Sarcopenia rather than BMI was associated with clinical outcomes in ASUC and played an important role in predicting the need for colectomy.

Sarcopenia and Vitamin D Deficiency in Patients with Crohn's Disease: Pathological Conditions That Should Be Linked Together

Sarcopenia is a prevalent condition in patients with Crohn’s disease (CD), representing an independent predictor factor for the development of major postoperative complications. Thus, a proper assessment of the muscle strength, by using different validated tools, should be deemed an important step of the clinical management of these patients. Patients with CD are frequently malnourished, presenting a high prevalence of different macro- and micro-nutrient deficiencies, including that of vitamin D. The available published studies indicate that vitamin D is involved in the regulation of proliferation, differentiation, and regeneration of muscle cells. The relationship between vitamin D deficiency and sarcopenia has been extensively studied in other populations, with interesting evidence in regards to a potential role of vitamin D supplementation as a means to prevent and treat sarcopenia. The aim of this review was to find studies that linked together these pathological conditions.

Role of Adipose Tissue in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs), chronic inflammatory disorders affecting the gastrointestinal tract, include Crohn's disease and ulcerative colitis. There are increasing clinical and experimental data showing that obesity, especially visceral adiposity, plays a substantial role in the pathogenesis of IBD. Obesity seems to be an important risk factor also for IBD disease severity and clinical outcomes. Visceral adipose tissue is an active multifunctional metabolic organ involved in lipid storage and immunological and endocrine activity. Bowel inflammation penetrates the surrounding adipose tissue along the mesentery. Mesenteric fat serves as a barrier to inflammation and controls immune responses to the translocation of gut bacteria. At the same time, mesenteric adipose tissue may be the principal source of cytokines and adipokines responsible for inflammatory processes associated with IBD. This review is particularly focusing on the potential role of adipokines in IBD pathogenesis and their possible use as promising therapeutic targets.

Degree of Creeping Fat Assessed by Computed Tomography Enterography is Associated with Intestinal Fibrotic Stricture in Patients with Crohn's Disease: A Potentially Novel Mesenteric Creeping Fat Index

BACKGROUND AND AIMS

Emerging evidence points to a link between creeping fat and the pathogenesis of Crohn's disease [CD]. Non-invasive assessment of the severity of creeping fat on cross-sectional imaging modality has seldom been investigated. This study aimed to develop and characterize a novel mesenteric creeping fat index [MCFI] based on computed tomography [CT] in CD patients.

METHODS

MCFI was developed based on vascular findings on CT in a retrospective cohort [n = 91] and validated in a prospective cohort [n = 30]. The severity of creeping fat was graded based on the extent to which mesenteric fat extended around the intestinal circumference using the vessels in the fat as a marker. The accuracy of MCFI was assessed by comparing it with the degree of creeping fat observed in surgical specimens. The relationship between MCFI and fibrostenosis was characterized by determining if these correlated. The accuracy of MCFI was compared with other radiographic indices [i.e. visceral to subcutaneous fat area ratio and fibrofatty proliferation score].

RESULTS

In the retrospective cohort, MCFI had moderate accuracy in differentiating moderate-severe from mild fibrostenosis (area under the receiver operating characteristic [ROC] curve [AUC] = 0.799; p = 0.000). ROC analysis in the retrospective cohort identified a threshold MCFI of > 3 which accurately differentiated fibrostenosis severity in the prospective cohort [AUC = 0.756; p = 0.018]. An excellent correlation was shown between MCFI and the extent of fat wrapping in specimens in the prospective cohort [r = 0.840, p = 0.000]. Neither visceral to subcutaneous fat area ratio nor fibrofatty proliferation score correlated well with the degree of intestinal fibrosis.

CONCLUSIONS

MCFI can accurately characterize the extent of mesenteric fat wrapping in surgical specimens. It may become another non-invasive measure of CD fibrostenosis.

Adipokine-Modulated Immunological Homeostasis Shapes the Pathophysiology of Inflammatory Bowel Disease

Inflammatory colon diseases, which are a global health concern, include a variety of gastrointestinal tract disorders, such as inflammatory bowel disease and colon cancer. The pathogenesis of these colon disorders involves immune alterations with the pronounced infiltration of innate and adaptive immune cells into the intestines and the augmented expression of mucosal pro-inflammatory cytokines stimulated by commensal microbiota. Epidemiological studies during the past half century have shown that the proportion of obese people in a population is associated with the incidence and pathogenesis of gastrointestinal tract disorders. The advancement of understanding of the immunological basis of colon disease has shown that adipocyte-derived biologically active substances (adipokines) modulate the role of innate and adaptive immune cells in the progress of intestinal inflammation. The biomedical significance in immunological homeostasis of adipokines, including adiponectin, leptin, apelin and resistin, is clear. In this review, we highlight the existing literature on the effect and contribution of adipokines to the regulation of immunological homeostasis in inflammatory colon diseases and discuss their crucial roles in disease etiology and pathogenesis, as well as the implications of these results for new therapies in these disorders.

Pre-treatment magnetic resonance enterography findings predict the response to TNF-alpha inhibitors in Crohn's disease

BACKGROUND

Identifying predictors of therapeutic response is the cornerstone of personalised medicine.

AIM

To identify predictors of long-term healing of severe inflammatory lesions based on magnetic resonance enterography (MRE) findings in patients with Crohn's disease (CD) treated with tumour necrosis factor alpha (TNF-α) inhibitors.

METHODS

This prospective longitudinal single-centre study included patients with clinically active CD requiring treatment with TNF-α inhibitors with at least one intestinal segment with a severe inflammatory lesion detected by MRE (segmental MaRIA ≥11). MRE data were obtained at baseline, and at weeks 14 and 46. The primary endpoint was healing of severe inflammatory lesions (MaRIA <11) in each segment. The secondary endpoint was healing of all severe inflammatory lesions on a per-patient analysis.

RESULTS

We included 58 patients with 86 intestinal segments with severe inflammatory lesions. At week 46, healing of severe lesions was found in 51/86 (59.3%) segments, and complete healing of inflammatory lesions in all segments was found in 28/58 (48.6%) patients. Multivariable analysis found baseline-negative predictors of long-term healing of severe inflammation were ileal (as opposed to colonic) location (OR 0.00, [0.00-0.56] P = 0.002) and presence of creeping fat on MRE (OR 0.00 [0.00-0.57]; P = 0.001). Persistence of segmental MaRIA score >10.6 at week 14 was a negative predictor of healing at week 46 (OR 0.3 [0.04--0.38]; P < 0.001).

CONCLUSION

In patients with CD, the absence of creeping fat detected at baseline MRE and location of severe inflammatory lesions are clinically relevant predictors of long-term healing of severe inflammation under treatment with TNF-α inhibitors.

Prevention of Postoperative Recurrence in CD: Tailoring Treatment to Patient Profile

Crohn's disease (CD) is an immune-mediated condition characterized by the transmural inflammation of the gut tissue, associated with progressive bowel damage often leading to surgical intervention. As operative resection of the damaged segment is not curative, a majority of patients undergoing intestinal resections for complicated CD present disease recurrence within 3 years after the intervention. Postoperative recurrence can be defined as endoscopic, clinical, radiological or surgical. Endoscopic recurrence rates within 1 year exceed 60% and the severity, according to the Rutgeerts' score, is associated with worse prognosis and can predict clinical recurrence (in up to 1/3 of the patients). Most importantly, about 50% of patients will undergo a reoperation after 10 years of their first intestinal resection. Therefore, the prevention of postoperative recurrence in CD remains a challenge in clinical practice and should be properly managed. We aim to summarize the most recent data on the definition, risk factors, assessment and treatment of postoperative CD recurrence.

Low Skeletal Muscle Index Adjusted for Body Mass Index Is an Independent Risk Factor for Inflammatory Bowel Disease Surgical Complications

Background

This study aims to evaluate sarcopenia defined by skeletal muscle index (SMI) with cutoffs adjusted for sex and body mass index as a predictive marker for postoperative outcomes among individuals with inflammatory bowel disease.

Methods

The SMI was measured using the cross-sectional computed tomography images at the lumbar spine. Multivariate logistic regression was performed to identify independent risk factors of postoperative complications.

Results

Ninety-one patients were included in the study. In multivariate analysis, sarcopenia (odds ratio = 5.37; confidence interval: 1.04-27.6) was predictive of infectious postoperative complications.

Conclusions

Sarcopenia as defined by the SMI is a predictor for 30-day postoperative infection complications in inflammatory bowel disease surgeries.

Magnetic resonance imaging assessment of body composition parameters in Crohn's disease

BACKGROUND

Body composition, currently evaluated by computed tomography scan, is related to poor evolution and severity of Crohn's disease (CD). Few MRI studies have been performed, yet it is the most commonly used imaging modality for the surveillance of the disease.

AIM

Evaluate the feasibility of MRI body composition measurement and compare the variation according to the activity of the disease.

METHODS

A cohort of 132 consecutive patients was studied. The visceral adiposity index (VAI), subcutaneous adiposity index (SAI) and skeletal muscle index (SMI) were measured. Patients were divided into 2 groups according to disease activity. Sarcopenic status was defined according to the cut off value (SMI < 38.9 cm²/m² in women and < 54.4 cm²/m² in men).

RESULTS

MRI measurements of body composition parameters were feasible and reproducible. After adjustment, sarcopenia was more common (2.07 [1.02; 4.27], p = 0.046), and the SMI (-4.90 [-9.36; -0.431], p = 0.032) was lower in active disease. The SAI was lower (-14.7 [-29.8; 0.258], p = 0.054) in active disease. The VAI tended to be higher with active disease (3.91 [-3.50; 11.9], p = 0.34), and the VAI/SAI+VAI ratio was higher (9.40 [4.72; 14.1], p<0.001).

CONCLUSION

Assessment of body composition is feasible and reproducible in routine MR and parameters are related to disease activity.

Risk of de-novo inflammatory bowel disease among obese patients treated with bariatric surgery or weight loss medications

BACKGROUND

An association between bariatric surgery and development of de-novo inflammatory bowel disease (IBD) has been observed.

AIM

To evaluate further the association among bariatric surgery, weight loss medications, obesity and new-onset IBD.

METHODS

Using Explorys, a population-based Health Insurance Portability and Accountability Act compliant database, we estimated the prevalence of de-novo IBD among patients treated with bariatric surgery (Roux-en-Y gastrojejunostomy, laparoscopic sleeve gastrectomy or gastric banding) (n = 60 870) or weight loss medications (orlistat, phentermine/topiramate, lorcaserin, bupropion/naltrexone and liraglutide) (n = 193 790) compared with obese controls (n = 5 021 210), between 1999 and 2018.

RESULTS

The prevalence of de-novo IBD was lower among obese patients exposed to bariatric surgery (7.72 per 1000 patients) or weight loss medications (7.22 per 1000 patients) compared with patients with persistent obesity not exposed to these interventions (11.66 per 1000 patients, P < 0.0001). The risk reduction for de-novo IBD was consistent across bariatric surgeries and weight loss medications with the exception of orlistat which was not associated with a reduction in risk for de-novo IBD compared with the persistent obese control cohort.

CONCLUSION

Obese patients undergoing treatment with bariatric surgery or weight loss medications are at a lower risk for developing de-novo IBD compared with persistently obese controls not exposed to these interventions. These data suggest that obesity and ineffective management of obesity are risk factors for de-novo IBD. Further research is needed to confirm these observations and understand potential mechanisms.

Role of Human Body Composition Analysis and Malnutrition Risk Questionnaire in the Assessment of Nutritional Status of Patients With Initially Diagnosed Crohn's Disease

Objective: This study was carried out to investigate the role and necessity of human body composition analysis in assessing the nutritional status of initially diagnosed Crohn's disease (CD) patients.

Methods: A total of 47 initially diagnosed CD patients were recruited. The skeletal muscle mass index (SMI), fat-free mass index (FFMI), body fat mass, body fat percent, visceral fat area (VFA), and body cell mass were determined with the Biospace Inbody S10 composition analyzer.

Results: In 47 patients with initially diagnosed CD, SMI could determine the muscular mass reduction that could not be determined by the body mass index (BMI) (35.3%), albumin (ALB) (65.6%), nutrition risk screening (NRS)2002 (25.0%), and Patient-Generated Subjective Global Assessment (PG-SGA) (55.6%). FFMI could determine the malnutrition that could not be determined by the BMI (58.8%), albumin (90.6%), NRS2002 (50.0%), and PG-SGA (55.6%). VFA in the fistulizing CD patients was significantly higher than in the stricturing and non-fistulizing, non-stricturing patients (P < 0.05). SMI and BMI had the same performance (P = 1.000) and general consistence (Kappa = 0.487, P = 0.001) in the assessment of malnutrition; SMI and ALB had different performance (P < 0.001) and inconsistence was noted (Kappa = 0.069, P = 0.489) in the assessment of malnutrition; the results of the nutrition assessment were different between SMI and NRS2002 (P = 0.002), and inconsistence was observed (Kappa = 0.190, P = 0.071). SMI and PG-SGA had the same performance in the assessment of nutrition (P = 0.143), but there was inconsistence (Kappa = 0.099, P = 0.464). FFMI and BMI had general consistence in the assessment of malnutrition (Kappa = 0.472, P < 0.001), but the positive rate determined by FFMI (85.1%) was markedly higher than that by BMI (63.8%) (P = 0.002). FFMI and ALB had different performance in the assessment of malnutrition (P < 0.001) and there was inconsistence (Kappa = −0.008, P = 0.877). FFMI and NRS2002 had the same performance in the assessment of malnutrition (P = 0.453), but the consistence was poor (Kappa = 0.286, P = 0.039). The results determined by SMI and PG-SGA were consistent (P = 0.727), but the consistence was poor (Kappa = 0.399, P = 0.006).

Conclusion: Human body composition analysis can identify the patients with muscular mass reduction that cannot be identified by commonly used nutrition assessment scales/parameters. Thus, it is helpful for the assessment of disease severity and also important for the nutrition assessment in CD patients.

Mesenteric excision surgery or conservative limited resection in Crohn's disease: study protocol for an international, multicenter, randomized controlled trial

Background

The structures of the mesentery including adipose tissue, nerves, and lymphatics play an important role in the pathogenesis and disease progression of Crohn’s disease (CD). Conventional surgical resection for CD usually does not involve resecting the mesentery en bloc with the specimen. This contrasts with complete mesocolic excision (CME) in colorectal cancer, which involves radical resection of the mesentery. Preliminary evidence from smaller studies suggests that applying the principle of mesocolic excision to CD surgery may reduce the risk of postoperative recurrence. This randomized controlled trial is designed to test whether applying the principles of mesocolic excision to CD results in reduced postoperative recurrence. It also aims to evaluate intra- and postoperative morbidity between the two approaches.

Methods

This international, multicenter, randomized controlled trial will randomize patients (n = 116) scheduled to undergo primary ileocolic resection to either receive extensive mesenteric excision (EME) or conventional ileocolic resection with limited mesenteric excision (LME). Five sites will recruit patients in three countries. In the EME group, the mesentery is resected following CME, while avoiding the root region, i.e., 1 cm from the root of the ileocolic artery and vein. In the LME group, the mesentery is retained, i.e., “close shave” or < 3 cm from the border of bowel. The primary end point will be surgical recurrence after surgery. The secondary end points will be the postoperative endoscopic and clinical recurrence, and intra- and postoperative morbidity. Demographics, risk factors, laboratory investigations, endoscopy, postoperative prophylaxis and imaging examination will be assessed. Analysis of the primary outcome will be on an intention-to-treat basis.

Discussion

If mesocolic excision in CD reduces postoperative disease recurrence and does not increase morbidity, this trial has the potential to change practice and reduce recurrence of CD after surgical resection.

Trial registration

Clinical Trials.gov, ID: NCT03769922. Registered on February 27, 2019.

Sarcopenia and visceral obesity assessed by computed tomography are associated with adverse outcomes in patients with Crohn's disease

BACKGROUND

Altered body composition may impact on the clinical course of Crohn's disease (CD) but is not detected by the simple body mass index (BMI) assessment.

AIM

To assess the prevalence of sarcopenia and visceral obesity by a single computed tomography (CT) slice, and its association with adverse events in an adult hospitalized CD cohort.

METHODS

88 CD patients who had abdominal CT scans during hospitalization were retrospectively enrolled. The skeletal muscle index (SMI) at the third lumbar vertebra level was used to assess sarcopenia. Sarcopenia was defined as a SMI <38.5 cm²/m² in women, <52.4 cm²/m² in men and visceral obesity as a visceral fat area ≥130 cm². Clinical malnutrition was defined by a BMI <18.5 kg/m². Univariate analysis was performed, and predictors for surgery in the follow-up were entered in a stepwise logistic regression model for multivariate analysis.

RESULTS

The prevalence of sarcopenia was 58%, malnutrition 21.6%, and visceral obesity 19.3%. Among sarcopenic patients, 49% had a normal BMI, 13.7% were overweight, and 1(2%) was obese. Sarcopenic CD patients had significantly more abscesses (51% vs 16.7%, p = 0.001), hospitalizations (61.2% vs 36.1%, p = 0.022) and digestive surgery (63.3% vs 27.8%, p = 0.001) than non-sarcopenic patients during the follow-up, whereas usual malnutrition assessment was not correlated with disease outcomes. In multivariate analysis, both sarcopenia and visceral obesity were associated with further occurrence of digestive surgery.

CONCLUSION

Both sarcopenia and visceral obesity were associated with adverse outcomes in severe CD patients whereas usual nutritional assessment was not.

Efficacy of enteral nutrition in patients with Crohn's disease on maintenance anti-TNF-alpha antibody therapy: a meta-analysis

Enteral nutrition (EN) is effective in Crohn's disease (CD) patients and has been shown to have an inhibitory effect on loss of response to anti-tumor necrosis factor (TNF)-alpha antibody therapy; however, the current level of evidence is not sufficient. The objective of this meta-analysis was to determine whether EN in combination anti-TNF-alpha antibody therapy is useful in maintaining remission. PubMed was used to identify all relevant studies. A total of nine articles were identified including one randomized control trial, two prospective cohort studies, and six retrospective cohort studies. We performed a meta-analysis on all these articles to assess the remission maintenance effect of EN (n = 857). The remission or response maintenance effect in the EN group was 203/288 (70.5%), which was higher than 306/569 (53.8%) in the non-EN group. The odds ratio for long-term remission or response using fixed effects model and random effects model were 2.23 (95% CI 1.60-3.10) and 2.19 (95% CI 1.49-3.22), respectively. The usefulness of EN was unclear in two prospective studies that were conducted immediately after remission induction with anti-TNF-alpha antibody therapy was detected. Differences in the definition of relapse and the observation period among articles were considered to be limitations. This analysis suggests that EN is effective for maintaining remission in patients already in remission or response as a result of anti-TNF-alpha antibody maintenance therapy.

Pharmacological Prevention and Management of Postoperative Relapse in Pediatric Crohn's Disease

Pediatric Crohn's disease (CD) is characterized by an aggressive course that commonly requires more intensive pharmacological and surgical treatments. In spite of the therapeutic advances in monitoring and management, including the widespread use of biologic therapy, the cumulative incidence of surgery in children with CD is still high. However, surgery is usually not curative and disease recurrence after small bowel resection is common. Gastrointestinal endoscopy is currently the gold standard to evaluate disease progression after surgery, but other non-invasive methods have been suggested. Although the efficacy of several drugs as medical prophylaxis to reduce the rate of disease recurrence following intestinal resection has been evaluated, selecting the most appropriate preventive therapeutic intervention remains a challenge. The current recommendations, mostly based on adult studies due to limited pediatric data, state that treatment should be guided by risk for recurrence. Low-risk patients may be given no prophylaxis or only 5-ASA. Maintenance enteral nutrition may also be considered. Thiopurines may be used in moderate risk of CD recurrence. In high risk patients for postoperative recurrence (extensive disease, short disease duration from diagnosis to surgery, recurrent surgery, long resected segment, surgery for fistulizing disease, disease complications, perianal disease, smoking), prophylactic treatment with anti-TNFα is recommended. subsequently, therapy should be guided by repeated measurement of objective measures including endoscopic re-evaluation at 6-12 months following surgery.

Role of Obesity, Mesenteric Adipose Tissue, and Adipokines in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs) are a group of disorders which include ulcerative colitis and Crohn's disease. Obesity is becoming increasingly more common among patients with inflammatory bowel disease and plays a role in the development and course of the disease. This is especially true in the case of Crohn's disease. The recent results indicate a special role of visceral adipose tissue and particularly mesenteric adipose tissue, also known as "creeping fat", in pathomechanism, leading to intestinal inflammation. The involvement of altered adipocyte function and the deregulated production of adipokines, such as leptin and adiponectin, has been suggested in pathogenesis of IBD. In this review, we discuss the epidemiology and pathophysiology of obesity in IBD, the influence of a Western diet on the course of Crohn's disease and colitis in IBD patients and animal's models, and the potential role of adipokines in these disorders. Since altered body composition, decrease of skeletal muscle mass, and development of pathologically changed mesenteric white adipose tissue are well-known features of IBD and especially of Crohn's disease, we discuss the possible crosstalk between adipokines and myokines released from skeletal muscle during exercise with moderate or forced intensity. The emerging role of microbiota and the antioxidative and anti-inflammatory enzymes such as intestinal alkaline phosphatase is also discussed, in order to open new avenues for the therapy against intestinal perturbations associated with IBD.

Body mass index and risk of inflammatory bowel disease: A systematic review and dose-response meta-analysis of cohort studies of over a million participants

The relationship between body mass index (BMI) and risk of inflammatory bowel disease (IBD) is controversial. We performed a dose-response meta-analysis to investigate the association between BMI and risk of incident ulcerative colitis (UC) and Crohn's disease (CD) using prospective cohort studies. A systematic search was conducted in MEDLINE/PubMed, SCOPUS, Cochrane, and Web of Science databases from inception to January 2019. DerSimonian and Laird random-effects model was used to estimate combined hazard ratios (HRs). Overall, 882 articles were screened, and 42 full-text articles were reviewed for inclusion using the study eligibility criteria. Five studies evaluated the association between BMI and IBD with 1 044 517 participants. Pooled results showed a significant association between participants affected by obesity and risk of CD (HR: 1.42, 95% CI: 1.18-1.71, I² : 0.00). There was a significant nonlinear association between BMI and risk of CD (P = .01, coeff = 0.5024). Pooled results did not show any significant association between being underweight and risk of UC (HR: 1.07, 95% CI: 0.96-1.19, I² : 0.00) or CD (HR: 1.11, 95% CI: 0.93-1.31, I² : 12.8). There was no difference in the risk for UC among participants affected by obesity compared with participants categorized as having normal BMI (HR: 0.96, 95% CI: 0.80-1.14, I² : 8.0). This systematic review and meta-analysis identified significant dose-response relationship between being affected by obesity, as a risk factor, and incidence of CD.

Systematic review of nutrition screening and assessment in inflammatory bowel disease

BACKGROUND

Malnutrition is prevalent in inflammatory bowel disease (IBD). Multiple nutrition screening (NST) and assessment tools (NAT) have been developed for general populations, but the evidence in patients with IBD remains unclear.

AIM

To systematically review the prevalence of abnormalities on NSTs and NATs, whether NSTs are associated with NATs, and whether they predict clinical outcomes in patients with IBD.

METHODS

Comprehensive searches performed in Medline, CINAHL Plus and PubMed. Included: English language studies correlating NSTs with NATs or NSTs/NATs with clinical outcomes in IBD. Excluded: Review articles/case studies; use of body mass index/laboratory values as sole NST/NAT; age < 16.

RESULTS

Of 16 studies and 1618 patients were included, 72% Crohn’s disease and 28% ulcerative colitis. Four NSTs (the Malnutrition Universal Screening Tool, Malnutrition Inflammation Risk Tool (MIRT), Saskatchewan Inflammatory Bowel Disease Nutrition Risk Tool (SaskIBD-NRT) and Nutrition Risk Screening 2002 (NRS-2002) were significantly associated with nutritional assessment measures of sarcopenia and the Subjective Global Assessment (SGA). Three NSTs (MIRT, NRS-2002 and Nutritional Risk Index) were associated with clinical outcomes including hospitalizations, need for surgery, disease flares, and length of stay (LOS). Sarcopenia was the most commonly evaluated NAT associated with outcomes including the need for surgery and post-operative complications. The SGA was not associated with clinical outcomes aside from LOS.

CONCLUSION

There is limited evidence correlating NSTs, NATs and clinical outcomes in IBD. Although studies support the association of NSTs/NATs with relevant outcomes, the heterogeneity calls for further studies before an optimal tool can be recommended. The NRS-2002, measures of sarcopenia and developments of novel NSTs/NATs, such as the MIRT, represent key, clinically-relevant areas for future exploration.

The Role of Adipose Tissue in the Pathogenesis and Therapeutic Outcomes of Inflammatory Bowel Disease

Though historically regarded as an inert energy store, adipose tissue is a complex endocrine organ, which is increasingly implicated in the pathogenesis of inflammatory bowel disease (IBD). Accumulating evidence points to visceral adipose tissue and specifically to its mesenteric component, or “creeping fat” as impacting on the disease course through its immunomodulatory properties. On the one hand, mesenteric fat acts as a physical barrier to inflammation and is involved in controlling host immune response to translocation of gut bacteria. On the other hand, however, there exists a strong link between visceral fat and complicated course of the disease with unfavorable therapeutic outcomes. Furthermore, “creeping fat” appears to play different roles in different IBD phenotypes, with the greatest pathogenetic contribution probably to an ileal form of Crohn’s disease. In this review, we summarize and discuss the existing literature on the subject and identify high-priority areas for future research. It may be that a better understanding of the role of mesenteric fat in IBD will determine new therapeutic targets and translate into improved clinical outcomes.

Visceral Adipose Tissue Is Associated With Stricturing Crohn's Disease Behavior, Fecal Calprotectin, and Quality of Life

BACKGROUND

Visceral adipose tissue (VAT) has been proposed to play a pathogenic role in Crohn's disease (CD); however, prospective clinical data are lacking. The aim was to evaluate whether VAT, beyond body mass index (BMI), is associated with CD behavior, disease activity, quality of life (QoL), or outcomes.

METHODS

Body composition data and clinical, anthropometric, disease activity (fecal calprotectin [FC]), and QoL scores were gathered prospectively on adults with CD at 0, 12, and 24 months. BMI and, VAT metrics (visceral adipose tissue volume [cm3]/height [m2] index and VAT:subcutaneous adipose tissue [SAT] ratio) were calculated. Inflammatory bowel disease-related surgery and hospitalization were recorded over extended follow-up (median, 51 months). Multivariable linear mixed effects and logistic regression analyses were performed.

RESULTS

Ninety-seven participants were assessed at baseline (55% male; median age, 31 years), 84 at 12 months, and 72 at 24 months. VAT:SAT was positively associated with stricturing disease behavior (log odds ratio [OR], 1.7; 95% confidence interval [CI], 0.32 to 3; P = 0.01) and elevated FC in patients with ileocolonic disease (β, 1.3; 95% CI, 0.32 to 2.3; P = 0.01). VAT:SAT was associated with lower QoL, particularly in those with ileal disease (β, -12; 95% CI, -19 to -4.5; P = 0.05). However, no prospective associations were observed between serial VAT measurements and time to surgery or hospitalization. No correlations were found between BMI and disease behavior, activity, or QoL.

CONCLUSIONS

VAT:SAT, rather than BMI, is associated with stricturing CD behavior, elevated FC, and reduced QoL in a disease distribution-dependent manner. Further studies are required to substantiate the role of VAT as a useful biomarker in CD.

Lower Subcutaneous or Visceral Adiposity Assessed by Abdominal Computed Tomography Could Predict Adverse Outcome in Patients With Crohn's Disease

BACKGROUND AND AIMS

Changes in body composition have been described in patients with Crohn's disease, but their predictive performances on disease evolution remain undefined. The aims of our study were to assess, in patients with Crohn's disease requiring abdominal computed tomography, body composition by computed tomography, and to study the outcome according to various body composition parameters at the time of the computed tomography.

METHODS

Patients with Crohn's disease who underwent abdominal computed tomography for suspected complications were retrospectively included. The definition of adverse outcome included death or need for surgery within 6 months of the computed tomography. Skeletal muscle index and visceral and subcutaneous adiposity indexes were calculated from tissue surface areas measured at the third lumbar vertebra, divided by the height squared.

RESULTS

The prevalence of underweight was 26.8% and the prevalence of sarcopenia was 33.6%. After gender adjustment, skeletal muscle index tended to be reduced in patients with adverse outcome, compared with patients without surgery or death [p = 0.07]. Moreover, subcutaneous adiposity index and visceral adiposity index were significantly lower in patients with surgery or death [p = 0.009 and p < 0.001, respectively]. These differences were almost equivalent in both genders for the subcutaneous adiposity index but were clearly stronger in men for the visceral adiposity index.

CONCLUSIONS

Subcutaneous and visceral adiposity indexes correlate inversely with adverse outcome in patients with Crohn's disease. Alteration of body composition assessed by computed tomography in these patients appears to be a marker of disease severity.

Obesity in Inflammatory Bowel Disease: Gains in Adiposity despite High Prevalence of Myopenia and Osteopenia

BACKGROUND

Rising rates of obesity have been reported in patients with inflammatory bowel disease (IBD); however, prospective data is lacking. The aim of this study is to prospectively evaluate body composition in adults with IBD over 24 months.

METHODS

Whole body dual energy X-ray absorptiometry (DXA) data was performed at 0 months, 12 months, and 24 months. Bone mineral density (BMD), fat mass index (FMI (kg)/height (m²)), appendicular skeletal muscle index (ASMI (kg)/height (m²)), visceral adipose tissue and the visceral adipose height index (VHI, VAT area (cm³)/height (m²)), and clinical and anthropometric assessments were performed at each time point. Multivariable linear mixed effects regression analyses were performed.

RESULTS

Initially, 154 participants were assessed at baseline (70% Crohn's disease, 55% male, median age 31 years), of whom 129 underwent repeated DXA at 12 months, and 110 underwent repeated DXA at 24 months. Amongst those undergoing repeated DXA, their body mass index (BMI) significantly increased over time, such that by 24 months, 62% of patients were overweight or obese (annual change BMI β = 0.43, 95%CI = [0.18, 0.67], p = 0.0006). Gains in BMI related to increases in both FMI and VHI (β = 0.33, 95%CI = [0.14, 0.53], p = 0.0007; β = 0.08, 95%CI = [0.02, 0.13], p = 0.001; respectively), whereas ASMI decreased (β = -0.07, 95%CI = [-0.12, -0.01], p = 0.01) with a concordant rise in rates of myopenia (OR = 3.1 95%CI = [1.2, 7.7]; p = 0.01). Rates of osteopenia and osteoporosis were high (37%), but remained unchanged over time (p = 0.23).

CONCLUSION

Increasing rates of obesity in patients with IBD coincide with decreases in lean muscle mass over time, while high rates of osteopenia remain stable. These previously undocumented issues warrant attention in routine care to prevent avoidable morbidity.

Sarcopenia is a Novel Predictor of the Need for Rescue Therapy in Hospitalized Ulcerative Colitis Patients

BACKGROUND AND AIMS

Acute severe ulcerative colitis [ASUC] affects one in four patients with UC. Clinical parameters perform modestly in predicting the need for rescue therapy. Sarcopenia and visceral adiposity predict natural history in Crohn's disease, but the role of such metabolic factors on ASUC outcomes is unknown. The aim of this study was to define the effect of sarcopenia and visceral adiposity on outcomes in ASUC.

METHODS

We studied patients hospitalized for ASUC who underwent an abdominal CT scan during the hospitalization. Quantification of skeletal muscle mass and visceral adiposity was performed by radiologists blinded to the outcome. Sarcopenia was defined as a skeletal muscle index of <55 cm2/m2 for men and <39 cm2/m2 for women. The primary outcome of interest was need for medical or surgical rescue therapy.

RESULTS

Our study included 89 patients with ASUC, among whom 39 [43.8%] patients required medical rescue therapy or surgery. Two-thirds of the cohort [70%] met the definition of sarcopenia [81% men, 48% women]. Patients with sarcopenia had similar disease characteristics and laboratory parameters to those with a normal muscle mass. However, a larger proportion of patients with sarcopenia required rescue therapy compared with those without (56% vs 28%, multivariable odds ratio [OR] 3.98, 95% confidence interval [CI] 1.12-14.1). Neither visceral [p = 0.23] nor subcutaneous adiposity [p = 0.53] predicted the need for rescue therapy.

CONCLUSIONS

Sarcopenia as determined on abdominal CT was a novel predictor of need for rescue therapy in hospitalized UC patients.

Clinical Implication of Sarcopenia in Patients with Inflammatory Bowel Disease

Recent studies have shown that inflammatory bowel disease (IBD) patients are affected by altered body composition, especially low muscle mass or sarcopenia. Detection of sarcopenia is important, as it can independently predict osteopenia, sarcopenic obesity, and poor disease outcomes during IBD progress. The challenges are needed to identify diagnostic and managing strategies for sarcopenia in IBD to improve disease outcomes and increase the quality of life in patients with IBD.

Anti-TNF Therapeutic Drug Monitoring in Postoperative Crohn's Disease

BACKGROUND

Anti-TNF prevents postoperative Crohn's disease recurrence in most patients but not all. This study aimed to define the relationship between adalimumab pharmacokinetics, maintenance of remission and recurrence.

METHODS

As part of a study of postoperative Crohn's disease management, some patients undergoing resection received prophylactic postoperative adalimumab. In these patients, serum and fecal adalimumab concentration and serum anti-adalimumab antibodies [AAAs] were measured at 6, 12 and 18 months postoperatively. Levels of Crohn's disease activity index [CDAI], C-reactive protein [CRP] and fecal calprotectin [FC] were assessed at 6 and 18 months postoperatively. Body mass index and smoking status were recorded. A colonoscopy was performed at 6 and/or 18 months.

RESULTS

Fifty-two patients [32 on monotherapy and 20 on combination therapy with thiopurine] were studied. Adalimumab concentration did not differ significantly between patients in endoscopic remission vs recurrence [Rutgeerts ≥ i2] [9.98µg/mL vs 8.43 µg/mL, p = 0.387]. Patients on adalimumab monotherapy had a significantly lower adalimumab concentration [7.89 µg/mL] than patients on combination therapy [11.725 µg/mL] [p = 0.001], and were significantly more likely to have measurable AAA [31% vs 17%, p = 0.001]. Adalimumab concentrations were lower in patients with detectable AAA compared with those without [3.59 µg/mL vs 12.0 µg/mL, p < 0.001]. Adalimumab was not detected in fecal samples. Adalimumab serum concentrations were lower in obese patients compared with in non-obese patients [p = 0.046].

CONCLUSION

Adalimumab concentration in patients treated with adalimumab to prevent symptomatic endoscopic recurrence postoperatively is, for most patients, well within the therapeutic window, and is not significantly lower in patients who develop recurrence compared with in those who remain in remission. Mechanisms of anti-TNF failure to prevent postoperative recurrence remain to be determined in these patients.

Relation of body mass index to risk of developing inflammatory bowel disease amongst women in the Danish National Birth Cohort

BACKGROUND

Crohn's disease (CD) has traditionally been associated with weight loss and low BMI, yet paradoxically obesity has recently been suggested as a risk factor for CD, but not for ulcerative colitis (UC). We therefore hypothesized that the relation between BMI and CD is U shaped.

AIM

To conduct a large population-based prospective cohort study of BMI and later risk of IBD, taking age at IBD diagnosis into account.

METHODS

A cohort of 74,512 women from the Danish National Birth Cohort, with BMI measured pre-pregnancy and 18 months after delivery, was followed for 1,022,250 person-years for development of IBD, according to the Danish National Patient Register. Associations were tested by Cox regression.

RESULTS

Overweight subjects (25≤BMI<30 kg/m2) had the lowest risk of CD, whereas obesity (BMI≥30kg/m2) increased the risk of CD at all ages, and low BMI (BMI<18.5kg/m2) associated with CD diagnosed at age 18-<40 years. Hence, using normal weight subjects as the reference, adjusted HRs for risk of developing CD (at age 18-<40 years) were 1.8(95%CI, 0.9-3.7) for underweight, 0.6(0.3-1.2) for overweight, and 1.5(0.8-2.7) for obese individuals (pre-pregnancy BMI). HRs were greater for BMI determined 18 months after delivery. Splines for CD risk according to waist:height ratio confirmed a U-shaped relationship with CD occurring <40 years, and a linear relationship with CD diagnosed at age 40+. There was no relationship between BMI and risk of UC.

CONCLUSION

For the first time, we demonstrate that both high BMI and low BMI are risk factors for CD. Underweight may be a pre-clinical manifestation of disease being present many years before onset with obesity being a true risk factor. This raises the question as to whether there may be two distinct forms of CD.

Sarcopenia is a predictive factor for intestinal resection in admitted patients with Crohn's disease

The relationship between skeletal muscle volume and the prognosis of patients with inflammatory bowel disease (IBD) remains undetermined. We conducted a retrospective study of 72 IBD patients who were admitted to the hospital due to disease exacerbation. We enrolled IBD patients who had undergone abdominal computed tomography and assessed the nutritional indices, such as the Onodera’s prognostic nutritional index (O-PNI) and the controlling nutritional status (CONUT) index. The L3 skeletal muscle index (SMI), which is the ratio of the cross-sectional area of skeletal muscles at the level of the third lumbar (L3) vertebra to the height squared, was used to identify sarcopenia. Sarcopenia, defined as a low SMI, was observed in 42% of all IBD patients (37% with Crohn’s disease (CD) and 48% with ulcerative colitis (UC)). In UC patients, the O-PNI and CONUT values, height, and albumin levels were significantly lower than in CD patients. The SMI strongly correlated with sex, body weight, albumin level, and O-PNI in IBD patients. Multivariate analysis using the Cox regression model demonstrated that the presence of sarcopenia (P = 0.015) and disease type (CD or UC) (P = 0.007) were significant factors predicting intestinal resection. The cumulative operation-free survival rate was significantly lower for sarcopenic patients than in all IBD patients (P = 0.003) and a stratified analysis of CD patients (P = 0.001) using the Kaplan–Meier method and log-rank test. The L3 skeletal muscle area is a prognostic factor for intestinal resection in patients with CD.

Body Composition in Crohn's Disease and Ulcerative Colitis: Correlation with Disease Severity and Duration

BACKGROUND

Results on body composition in Crohn's disease (CD) and ulcerative colitis (UC) have been heterogeneous and are lacking from Asia. Present study assessed body composition in CD/UC and correlated it with disease severity/duration.

METHODS

Patients of CD/UC following between Dec 2014 and Dec 2015 who consented for bioimpedance analysis for body fat measurement were included. Lean mass and fat-free mass index (FFMI) were calculated with standard formulae. Visceral fat area (VFA), subcutaneous fat area (SCA), and visceral to subcutaneous fat ratio (VF/SC) were evaluated in CD patients on abdominal CT.

RESULTS

Lean mass in CD (n = 44, mean age: 41.2 ± 15.8 years, 73% males) was significantly lower than UC (n = 53, mean age: 33.2 ± 11.2 years, 68% males; 44.2 ± 7.8 versus 48.3 ± 8.4 Kg, p = 0.01). In both UC/CD, disease severity was associated with nonsignificant decline in BMI (UC: 22.1 ± 4.9 versus 20.2 ± 3.2 versus 19.9 ± 3.2 kg/m², p = 0.23; CD: 22.1 ± 4.2 versus 19.9 ± 2.3 versus 19.7 ± 4.2 kg/m², p = 0.18) and fat mass (UC: 10.9 ± 8.9 versus 8.1 ± 5.9 versus 5.7 ± 3.6 kg, p = 0.14; CD: 11.2 ± 7 versus 7.9 ± 4.4 versus 7.2 ± 5.9 kg, p = 0.16), and disease duration was associated with significant decline in FFMI (p < 0.05). In CD, disease severity was associated with nonsignificant decline in SCA and increase in VF/SC.

CONCLUSIONS

CD patients have lower lean mass than UC. Body fat decreases with increasing disease severity and fat-free mass decreases with increasing disease duration in both UC/CD.