IBD Updates: Microbiome afer surgery, Anti-TNF agents NOT changing hospitalizations/surgeries, Biobanking Genetics

X Fang et al. Inflamm Bowel Dis 2021; 27: 603-616. Full Text: Gastrointestinal Surgery for Inflammatory Bowel Disease Persistently Lowers Microbiome and Metabolome Diversity

  • Methods: The UC San Diego IBD Biobank was used to prospectively collect 332 stool samples (every 6 months) from 129 subjects (50 ulcerative colitis; 79 Crohn’s disease). Of these, 21 with Crohn’s disease had ileocolonic resections, and 17 had colectomies.
  • Key finding: Intestinal surgeries in IBD patients seem to reduce the diversity of the gut microbiome and metabolome in IBD patients. Colectomy has a larger effect than ileocolonic resection.
  • Limitations: Confounding variables (eg. antibiotics) and selection bias (patients with more severe disease

C Verdon et al. Inflamm Bowel Dis 2021; 27: 655-661. No Change in Surgical and Hospitalization Trends Despite Higher Exposure to Anti-Tumor Necrosis Factor in Inflammatory Bowel Disease in the Québec Provincial Database From 1996 to 2015

Key findings:

  • 34,644 newly diagnosed patients with IBD (CD = 59.5%)
  • The probability of first and second hospitalizations remained unchanged in Québec and the probability of major surgery was low overall but did increase despite the higher and earlier use of anti-TNFs. However, the authors note that “in the present study, biologics use under the public reimbursement plan was 13% in patients with UC and 16% in patients with CD.”
  • My take: This study is provocative but probably misleading; it is quite likely that use of anti-TNF agents do lower the risk of hospitalization and surgery.

K Gettler et al. Gastroenterol 2021; 160: 1546-1557. Full text PDF: Common and Rare Variant Prediction and Penetrance of IBD in a Large, Multi-ethnic, Health System-based Biobank Cohort

  • Methods: The authors used the Mount Sinai BioMe Biobank, which contains genetic data on
    32,595 patients. After rigorous phenotype validation, 19,541 individuals were retained, of whom 339 were IBD patients (273 CD, 28 UC, and 37 individuals who were classified as both) and 19,202 were controls
  • Key findings: In this study, the authors identified several rare VEO-IBD variants with high genetic penetrance using the biobank samples and then replicated results in large case control African American and European data sets.
  • One of the variants with the highest genetic penetrance located in the gene LRBA was predicted to result in a deleterious change to the amino acid structure. Reduced expression of CTLA-4 secondary to the variants we identified in LRBA may result in autoinflammation that contributes to IBD. “Targeting reduced CTLA-4 expression is an exciting treatment venue, because expression of CTLA-4 has been shown to be increased by chloroquine treatment in vitro.”
  • Enteropathy is present in 63% of all known individuals with LRBA deficiency, with 27% having chronic diarrhea as the presenting symptom

Mangroves in John Pennekamp State Park (Key Largo)

For the Next Insurance Appeal: Therapeutic Drug Monitoring in Adalimumab Treatment (Pediatrics) & Satire on Prior Authorizations

There is a lot of data supporting the use of therapeutic drug monitoring (TDM) for anti-TNF agents. A recent study (MJ Kim et al. JPGN 2021; 72: 870-876. Therapeutic Drug Monitoring of Adalimumab During Long-term Follow-up in Paediatric Patients With Crohn Disease) adds to this data and supports increased adalimumab (ADL) dosing if below target values.

In this prospective study of 31 pediatric patients with Crohn’s disease, the authors found correlations between ADL values and the endpoints of clinical remission (CR) and mucosal healing (MH). The authors checked TLs at 4 months, 1, 2, and 3 years. Key findings:

  • The median trough levels (TLs) of ADL were higher in patients in CR (7.6 ± 3.5 μg/mL) than in patients with active disease (5.1 ± 2.2 μg/mL).
  • ADL TLs were significantly higher in patients who achieved MH than in those who did not (14.2 ± 7.6 vs 7.8 ± 5.2 μg/mL). 
  • The optimal cut-point for predicting MH at 1 year of ADL treatment was 8.18 μg/mL
  • MH was noted in 42% at 4 months and 55% at 1 yr; CR was noted in 90% at 4 months and 84% at 1 yr. ADL treatment was associated with positive effects on growth indicators as well.

The authors discuss TDM for anti-TNF therapy, noting that for infliximab, the AGA recommends values >5 mcg/mL and the ACG >7.5 mcg/mL. There are fewer studies of ADL TDM -prior studies have indicated goals of >5.8, >7.1, >8, and >8.1; thus, this study is in agreement with these prior studies.

My take: This study further supports the value of TDM; better drug levels correlate with better outcomes.

Related blog posts:

Fort Jefferson, Dry Tortugas. The fort has reportedly 16 million bricks (I didn’t confirm this figure).

More satire —On Prior Authorizations:

Trial by Diet Approach for Crohn’s Disease in Children

RS Boneh et al. Clin Gastroenterol Hepato 2021; 19: 752-759. Dietary Therapies Induce Rapid Response and Remission in Pediatric Patients With Active Crohn’s Disease

The authors collected  data from a multicenter randomized trial of the CD exclusion diet (CDED) in children (mean age, 14.2 ± 2.7 y) with Crohn’s disease who were randomly assigned to groups given either exclusive enteral nutrition (EEN, n = 34) or the CDED with 50% (partial) enteral nutrition (PEN) (n = 39). 

The CDED has been discussed previously on this blog; it aims to avoid animal and saturated fat, milk fat, gluten, specific emulsifiers, taurine, red (reduced heme) and processed meat, and certain fibers from some fruits and vegetables. In addition to excluding patients who received competing therapies (eg. steroids, immunomodulators, and biologics), the authors excluded patients with isolated large bowel disease (L2).

Key findings:

  • At week 3 of the diet, 82% of patients in the CDED group and 85% of patients in the EEN group had a dietary response or remission. Median serum levels of C-reactive protein had decreased from 24 mg/L at baseline to 5.0 mg/L at week 3 (P < .001)
  • Among the 49 patients in remission at week 6, 46 patients (94%) had had a diet response or remission by week 3 and 81% were in clinical remission by week 3

The authors note that the rapid response to dietary therapy suggests a role for a ‘trial by diet’. As such, dietary therapy could be used as monotherapy, for patients failing other therapies, or as a bridge to biological therapy. The authors note that the exact reasons for response to dietary therapy are unsettled and could be “due to both foods excluded and foods enriched in the diet.” In addition, they note that diet appears to be a trigger for inflammation and that reintroduction of foods leads to rebound in inflammation (eg. higher calprotectin) and dysbiosis.

My take: This study shows that dietary therapy works quickly. In this small study, the effectiveness of combined CDED with 50% PEN was similar to EEN.

Related blog posts:

Rhododendrum

NY Times: Crohn’s Disease is On the Rise (4/26/21)

NY Times: Crohn’s Disease Is on the Rise

Some excepts:

Dr. Joseph D. Feuerstein, gastroenterologist at Beth Israel Deaconess Medical Center in Boston… “It’s rising in incidence and prevalence throughout the world,” he said, and gastroenterologists are still trying to figure out why it shows up when it does in different people.

Crohn’s disease was first described in 1932 by Dr. Burrill B. Crohn…

Prompt diagnosis and appropriate therapy to suppress inflammation in the digestive tract are extremely important because a delay can result in scar tissue and strictures that are not reversed by medication…

Crohn’s is not curable and most patients have to stay on medication indefinitely. That can create yet another stumbling block. The biologics are very costly…

Related blog posts:

Passive Smoking and Worsening Crohn’s Disease

S Scharrer et al. Inflamm Bowel Dis 2021; 27: 379-385. Passive Smoking Increases the Risk for Intestinal Surgeries in Patients With Crohn’s Disease

This was a retrospective cohort study which included 169 patients who never smoked actively, 91 patients (54%) were exposed to passive smoking.

Key finding:

  • Exposed patients were more likely to undergo intestinal surgery than nonexposed patients (67% vs 30%; P < 0.001). Multivariate Cox regression analysis revealed that passive smoking was an independent risk factor for intestinal surgeries (hazard ratio, 1.7; 95% CI, 1.04–2.9; P = 0.034)

The associated editorial (RA John, RB Geary, pgs 386-387, Full Text: Smoking Cessation for Patients With Crohn Disease: Not Just for the Patient?) makes several useful points:

  • Smoking has long been identified as one of the strongest environmental risk factors for both the development of Crohn disease (CD) and the worsening of the disease course.
  • Studies in smokers with CD have reported that the risk of flares and complications matches that of nonsmokers with CD after 1 year of abstinence.
  • It would be reasonable to expect that a similar risk reduction exists for patients who can become passive-smoke-free. In addition, their likelihood of remaining smoke-free themselves is increased if they live in a smoke-free household.

My take (from editorial): “Clinicians should consider widening the scope of smoking cessation counseling to include not just patients but also their cohabitants.”

STRIDE II -Updated Crohn’s Disease Target Goals

From Tauseef Ali’s Twitter Feed — a summary slide of Crohn’s disease targets for both pediatric and adult patients and a slide showing typical response/remission/healing times to medications.

From the following article: D Turner et al. Gastroenterology (12/31/20, Online Ahead of Print): DOI: 10.1053/j.gastro.2020.12.031 STRIDE-II: An Update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) Initiative of the International Organization for the Study of IBD (IOIBD): Determining Therapeutic Goals for Treat-to-Target strategies in IBD

Recommendations were based on a systematic review of the literature and iterative surveys of 89 IOIBD members, recommendations were drafted and modified in two surveys and two voting rounds.

Getting Lost in the Pathophysiology of Inflammatory Bowel Disease

A recent review (JT Chang. NEJM 2020; 383: 2652-2664. Pathophysiology of Inflammatory Bowel Diseases) provides an in-depth description of the pathophysiology of inflammatory bowel disease (IBD). Digesting the article is akin to putting together a 1000 piece puzzle due to the complex interactions.

Some of the Key Points:

  • Based on genomewide association studies, there are “more than 240 risk variants that affect intracellular pathways recognizing microbial products (eg. NOD2); the autophagy pathway, which facilitates recycling intracellular organelles and removal of intracellular microorganisms (eg. ATG16L1); genes regulating epithelial barrier function (eg. ECM1); and pathways regulating innate and adaptive immunity (eg. IL23R and IL10).”
  • In this article, Figure 1 and 2 describe the intestinal mucosal immune system in health and disease. At baseline, this system promotes an antiinflammatory state “by virtue of active down-regulation of immune responses. For example, unlike macrophages in other parts of the body, intestinal macrophages do not produce inflammatory cytokines” after exposure to bacteria.

Other points:

  • Dysbiosis is present with IBD; however, studies have been “unable to infer causal relationships.”
  • Germ-free mice, when given fecal material from patients with IBD have increased susceptibility to colitis as compared to those who received fecal material from a healthy person.
    • Thus, this leads to potential for mitigating intestinal inflammation by modulation of the microbiome.
    • However, the authors note that humans are colonized by trillions of viral, fungal, bacterial, and eukaryotic microbes.
  • Other components of IBD pathophysiology: reduced mucus layer, increased microbial adherence, dysregulation of tight junctions/increased permeability, dysfunctional Paneth cells, TNF, IL23, IL12, IL6, IL 17A, IL17F, IL22, Interferon-gamma, integrins, JAK inhibitors, T-cells

My take: This article is a useful reference detailing the complexity of IBD pathophysiology and tries to summarize a whole textbook of information into 12 pages.

Related blog posts:

Disease Activity, Not Medications, Linked to Neonatal Outcomes Among Women with IBD

U Mahadevan at el. Gastroenterology; 2020: (in press) DOI:https://doi.org/10.1053/j.gastro.2020.11.038. Pregnancy and Neonatal Outcomes after Fetal Exposure To Biologics and Thiopurines among Women with Inflammatory Bowel Disease

Methods: Between 2007 and 2019, pregnant women with IBD were enrolled in a prospective, observational, multicenter study across the United States (PIANO registry). 

Key findings:

  • Exposure was to thiopurines (242), biologics (642) or both (227) versus unexposed (379)
  • Medication exposure did not increase the rate of congenital malformations, spontaneous abortions, preterm birth, LBW, and infections over the first year of life
  • Higher disease activity was associated with risk of spontaneous abortion (HR 3.41, 95% CI 1.51-7.69) and preterm birth with increased infant infection (OR 1.73, 95% CI 1.19-2.51)

My take: This study provides some reassurance that treatments for IBD are unlikely to affect neonatal outcomes; however, increased IBD activity does affect outcomes

Related blog post: IBD and Pregnancy

Histologic Healing and IBD Outcomes

Several recent studies recently evaluated outcomes based on histologic healing compared to endoscopic remission.

RK Pai et al. Clin Gastroenterol Hepatol 2020; 18: 2510-2517. Full text link: Complete Resolution of Mucosal Neutrophils Associates With Improved Long-Term Clinical Outcomes of Patients With Ulcerative Colitis n=281.Key findings:

  • “We found histologic evidence of UC activity (Geboes score ≥ 2B.1) in biopsies from 182 patients (65%) and endoscopic evidence of UC activity in 149 patients (53%) (substantial agreement, κ = 0.60).”
  • “Histologic features of UC activity were associated with increased rates of systemic corticosteroid use, colectomy, and hospitalization in the entire cohort (P < .05 for all) and associated with increased rates of systemic corticosteroid use in an analysis limited to patients in endoscopic remission (P < .001).”

B Christensen et al. Clin Gastroenterol Hepatol 2020; 18: 2518-2525. Full text link: Histologic Healing Is More Strongly Associated with Clinical Outcomes in Ileal Crohn’s Disease than Endoscopic Healing This was a a retrospective study of 101 patients with CD (52% male) isolated to the terminal ileum. Key findings:

  • At ileo-colonoscopy, 63% of patients had endoscopic healing and 55% had histologic evidence of healing. The level of agreement between endoscopic and histologic activity was fair (62%, K = 0.2250, P = .0064)
  • On multivariate analysis, only histologic healing was associated with decreased risk of clinical relapse (hazard ratio [HR], 2.05; 95% CI, 1.07–3.94; P = .031), medication escalation (HR, 2.17; 95% CI, 1.2–3.96; P = .011), and corticosteroid use (HR, 2.44; 95% CI, 1.17–5.09; P = .018).
Kaplan-Meier analysis of effect of endoscopic and histologic activity on (A) clinical relapse-free survival versus histologic healing, (B) clinical relapse-free survival versus endoscopic healing

D Kevans et al. Inflamm Bowel Dis 2020; 26: 1722-1729. Histological Markers of Clinical Relapse in Endoscopically Quiescent Ulcerative Colitis Key finding: In endoscopically quiescent UC (n=76), active histological inflammation …[is] adjunctive histological marker associated with increased likelihood of disease relapse. The associated editorial (1730-32 by Asher Kornbluth) quotes Voltaire: “A wise Italian says that the best is the enemy of the good.” He notes that there is “a very real risk of abandoning an effective drug while chasing the goal of some yet to be universally defined histologic remission.” Currently organizational guidelines (ACG, AGA, ECCO, IOIBD) do NOT suggest the use of histologic normalization as an endpoint at this point.

My take: These studies show that histologic healing in ileal Crohn’s disease and in ulcerative colitis are associated with better outcomes that endoscopic appearance. However, there are a lot questions because many patients, possibly a majority, will not achieve histologic healing despite aggressive treatment. Related technical issues include how many biopsies are needed to assess histology and having a validated histologic assessment.

Related blog posts:

Disclaimer: This blog, gutsandgrowth, assumes no responsibility for any use or operation of any method, product, instruction, concept or idea contained in the material herein or for any injury or damage to persons or property (whether products liability, negligence or otherwise) resulting from such use or operation. These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  Because of rapid advances in the medical sciences, the gutsandgrowth blog cautions that independent verification should be made of diagnosis and drug dosages. The reader is solely responsible for the conduct of any suggested test or procedure.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

In Case You Missed It: IBD Year in Review (Eric Benchimol)

I did not have the opportunity to hear this #NASPGHAN20 lecture but Dr. Benchimol has shared his slides. Link to Dropbox Slides: IBD Clinical Science: Year in Review

Some of the key points on slides (links to articles below):

Some screenshots:

Links to many of the referenced papers:


Related links: