More on Gut Microbiome and Crohn Disease

Earlier this week on NPR there was a story summarizing the altered microbiome in Crohn disease and a related recent paper; here’s the link: Mix Of Gut Microbes May Play Role In Crohn’s Disease.  Other media outlets covered the story too:

The graphical abstract (Cell Host & Microbe, Volume 15, Issue 3, 382-392, 12 March 2014) is noted below:

Graphical Abstract

The link to the full study is listed below if you want to see the source article.  The amount of data that is presented is impressive but easy to follow with the figures:

Full link to article (from Kipp Ellsworth twitter feed): http://goo.gl/603Rbz 

Related blog posts:

Calprotectin: Part of diagnostic algorithm for IBD?

Full text available at this link from Jeremy Adler: cghjournal.org/article/S1542-3565(13)01044-6/abstract#.Ut5vnV5z8Cw.twitter …

This article describes the use of fecal calprotectin (FC) levels as a screen for inflammatory bowel disease.  The false-negative rate for this assay is related to pre-test probability of having IBD.  Thus, in patients with a low probability of IBD, a normal calprotectin may allow avoidance of endoscopic evaluation and may be “particularly cost-effective when baseline clinical suspicion for IBD is low to moderate…the low FC cutoff value of 50 μg/g would substantially reduce the likelihood of false-negative FC, minimizing delayed diagnosis of true IBD.” In those with persistent symptoms, the article’s algorithm recommends proceeding with endoscopic evaluation.

Excerpt from abstract:

Conclusions

Screening adults and children to measure fecal levels of calprotectin is effective and cost-effective in identifying those with IBD on a per-case basis when the pre-test probability is ≤75% for adults and ≤65% for children. The utility of the test is greater for adults than children. Increasing the FC cutoff level to ≥50 μg/g increases diagnostic accuracy without substantially increasing total cost.

Related blog posts:

UC SUCCESS

The results of the “UC SUCCESS” trial show that combination therapy with infliximab and azathioprine is more effective than either medication as monotherapy in ulcerative colitis (UC) (Gastroenterol 2014; 146: 392-400). This study findings are similar to the SONIC trial in Crohn’s disease (CD).

Study Design: randomized, double-blind trial with evaluation at 16 weeks with a total of 239 patients.  In patients assigned to infliximab (IFX) alone, they were given daily oral placebo pills. In patients with azathioprine monotherapy (AZA), dosed at 2.5 mg/kg/day, they also received placebo infusions.  Patients had moderate to severe UC as defined by Mayo scores at baseline and had not responded adequately to a course of corticosteroids.  All patients were naive to tumor necrosis factor α antagonists (anti-TNFα).  Mean age was approximately 40 years.

Results:

  • IFX/AZA had a 39.7% corticosteroid-free remission at week 16 compared with 22.1% with IFX monotherapy and 23.8% with AZA monotherapy.
  • Mucosal healing at week 16 was evident in 62.8% of combination group compared with 54.6% IFX monotherapy and 36.8% with AZA monotherapy.
  • Serious adverse events were noted more frequently in the AZA monotherapy group, though this did not reach statistical significance.
  • A subset of patients had antibodies to infliximab (ATIs) measured.  ATI-positivity was more common with IFX monotherapy (19%, 7 of 37) than for IFX/AZA combination (3%, 1 of 31)

While this study indicates that for moderate to severe UC combination therapy with IFX/AZA was superior in this age group, there were several limitations.  Given the slow onset of action of azathioprine, more patients may have responded to this therapy if longer treatment duration was studied.

Take-home message: Combination therapy for UC, like CD, is more effective.  In this small study population, the adverse events were not increased. In the pediatric population, particularly males, the concern for malignancy in patients (especially males) treated with combination therapy may limit the frequency of combination therapy.

Related blog posts:

Other recent IBD articles of interest:

Inflamm Bowel Dis 2014; 20: 291-300. “Malignancy and Mortality in Pediatric Patients with Inflammatory Bowel Disease”  This article presented the results of a survey of 20 European countries and Israel.  Key finding: 18 cases of cancer and 31 deaths in 44 children. 5 of the deaths were due to cancer; the most common cause of mortality was infectious (n=14).  In this cohort, all HSTCL or EBV-positive lymphomas were treated with thiopurine monotherapy.

Inflamm Bowel Dis 2014; 20: 196-212.  “Opportunistic Infections Due to Inflammatory Bowel Disease Therapy”  This review article covers a broad range of pathogens and includes recommendations for prophylaxis and treatment (Table 3).  In addition the authors  provide suggestions for checking for several infections prior to treatment and vaccinations.

Superiority of Anti-TNF Therapy in Children

This study’s conclusion comes as no surprise:

“In children newly diagnosed with comparably severe CD, early monotherapy with anti-TNFα produced better overall clinical and growth outcomes at 1 year than early monotherapy with an immunomodulator. Further data will be required to best identify children most likely to benefit from early treatment with anti-TNFα therapy.”

Here’s the reference:

Gastroenterology Volume 146, Issue 2 , Pages 383-391, February 2014

Here’s a link to the full text article:  Increased Effectiveness of Early Therapy with Anti-Tumor Necrosis Factor-α Versus an Immunomodulator in Children with Crohn’s Disease

Methods: “From 2008 through 2012 at 28 pediatric gastroenterology centers in North America. Patients were managed by physician dictate. From 552 children (median age, 11.8 y; 61% male; 63% with pediatric CD activity index scores >30; and median C-reactive protein level 5.6-fold the upper limit of normal), we used propensity score methodology to identify 68 triads of patients matched for baseline characteristics who were treated with early anti-TNFα therapy, early immunomodulator, or no early immunotherapy.”

Another reference/link from same issue:

Accuracy of Magnetic Resonance Enterography in Assessing Response to Therapy and Mucosal Healing in Patients with Crohn’s Disease

Does Sun Exposure Lower the Risk of Crohn Disease?

An intriguing recent study suggests that individuals who spend more time outside are less likely to develop Crohn disease (CD) (Inflamm Bowel Dis 2014; 20: 75-81).

In this prospective cohort study from France, 123 cases of inflammatory bowel disease (45 CD, 71 ulcerative colitis, and 7 indeterminant colitis)  developed among the 91,870 women in the study.  The study period had a mean followup of 13.1 years and followed women between 40 and 65 years. The authors estimated residential sun exposure by utilizing a database (derived from satellite collection) containing the mean daily ultraviolet radiation dose for each French county.

Key findings:

  • Higher levels of sun exposure were associated with a decreased risk of Crohn disease with a Hazard Ratio (HR) of 0.49.
  • Sun exposure did not affect the likelihood of developing UC (HR 1.21).
  • In women with information about dietary vitamin D intake, higher sun exposure had a HR of 0.29 for developing CD.  That being said, the authors note a low dietary vitamin D intake in their population.

Despite the large cohort, this study has a number of limitations. The absolute number of IBD patients can lead to a Type 1 error (false-positive conclusion).  In addition, the age of the study population and the lack of data regarding individual sun exposure limit the conclusions as well.  Besides these factors, there may be confounders such as changes in diet and soil exposure which are not accounted for.

At the same time, there have been other studies which have shown a latitude effect.  As with this study, those living in sunny areas had a lower incidence of CD.

Bottomline: This study suggests that additional sun exposure is associated with a lower risk of developing Crohn disease.  Whether this lower risk is directly through better vitamin D levels or simply an epiphenomenon is unclear.

Other recent unrelated studies:

Gut 2013; 62: 1122-30.  A randomized phase 1 study of etrolizumab (rhuMAb β-7) in moderate to severe ulcerative colitis.  Etrolizumab is an adhesion cell molecular blocker.

Inflamm Bowel Dis 2014; 20: 21-35.  Meta-analysis of 23 randomized controlled trials of probiotics for UC, Pouchitis, and CD.  Probiotics, in particular VSL#3, increased UC remission rates and helped maintain remission in patients with pouchitis.

Inflamm Bowel Dis 2014; 20: 213-27. Review article of cutaneous manifestations of inflammatory bowel disease.  Good pictures of multiple problems including metastatic Crohn disease, erythema nodosum, pyoderma gangrenosum, Sweet’s syndrome, aseptic abscess syndrome, and epidermolysis bullosa acquisita.

Inflamm Bowel Dis 2013; 19: 1753-63.  Review on hair loss associated with inflammatory bowel disease. Remember telogen effluvium?

Related posts:

For those who read from the top to the very bottom, here’s a tangential question: Do you know what a “sun dog” is?   Sun dog – Wikipedia, the free encyclopedia

Sanjay Gupta is Wrong… about Stem Cell Therapy

According to a 3 min video (and article) publicized on twitter by Dr. Sanjay Gupta, Stem Cell therapy for Crohn disease is 97% effective. ow.ly/smrJM I sent him a tweet asking for data to support this figure but have not heard back.  That being said, there are very few treatments that work in 97% of patients with any chronic disease.

The context of the video regards a model who has had 75 hospitalizations for Crohn disease and is unable to tolerate standard treatment.  “Thus far, there is a 97 percent success rate with this procedure, but it’s not fully covered by insurance, so Jocelyn must find the money for the procedure, her travel, and the long recovery.”

To my knowledge, stem cell therapy, while promising, for Crohn disease remains an experimental treatment without any large studies proving its effectiveness. 

An abstract at DDW last year (Stem Cell Transplantation Halts Crohn’s Disease – Medscape) reported that among the 22 patients in the stem cell treatment group (who were refractory to multiple other medications), 40% had mucosal healing and 58% had segmental healing. The presenting physician, Dr. Christopher Hawkey, noted ‘there were serious adverse events and many patients were not cured…. We need controlled trials showing a long-term risk/benefit ratio.’

Another study (Blood. 2010;116:6123-6132) with 24 patients, reported that “the percentage of clinical relapse-free survival defined as the percent free of restarting CD medical therapy after transplantation is 91% at 1 year, 63% at 2 years, 57% at 3 years, 39% at 4 years, and 19% at 5 years.”

Bottomline: I think the information in the video is not accurate.  Inevitably, it will lead to a lot of ill-informed questions by families.  When a respected physician posts this type of unsupported information, it has the potential to undermine not just his credibility but other physicians as well. Perhaps, Dr. Gupta will consider revising this information.

Related article:

Clin Gastroenterol Hepatol 2014; 12: 64-71: “A phase 2 study of allogeneic mesenchymal stromal cells for luminal Crohn’s disease refractory to biologic therapy.” Results: among the 15 patients (of 16) who completed the study, the mean CDAI score was reduced from 370 to 203.  Twelve patients had a clinical response and eight had clinical remission.  All patients received 4 weekly infusions of mesenchymal stromal cells.  One patient had a stage 1 adenocarcinoma (colon) but the authors think that this was likely present prior to the infusions. Why this study is important? If shown effective in larger studies, mesenchymal stromal cells  are much safer than allogeneic stem cells as donor to recipient matching is not needed nor chemotherapeutic marrow conditioning.

IBD Update 2014 (part 2)

5. Inflamm Bowel Dis 2013; 19: 2927-36.  This reference is another article that tries to help discuss the risks and benefits of biologic therapy for pediatric inflammatory bowel disease.  After reviewing the potential risks, the authors provide their “Option Grid” (Page 2932).  The authors state, “in summary, the adult literature supports the concept of the early use of combination therapy…the risks associated with anti-TNF therapy are really not significantly different as compared with thiopurine therapy and perhaps in some cases safer.  Therefore, we should be moving closer to the idea of using anti-TNF therapy early, with or without an immunomodulator.  In the sickest patients, combination therapy probably adds benefit, and then once in remission, consideration can be given for stopping one of the medications, more likely the thiopurine.

6. Gut 2013; 62: 689-94.  Risk of ischemic heart disease in patients with inflammatory bowel disease: a nationwide Danish cohort study.  From 1997 to 2009, the authors compared 28,833 IBD persons to >4.5 million persons without IBD who were matched for age, gender, socioeconomic status, and calendar year.  With a mean follow-up of 13 years, they identified a 59% higher incidence rate of ischemic heart disease in patients with IBD.  Long-term use of immunosuppressive medications, such as azathioprine and anti-tumor necrosis factor-alpha agents, was not associated with an increased risk of ischemic heart disease.

7.   Gastroenterol 2013; 145: 1459-63.  AGA Guideline for Use of Thiopurines, Methotrexate, and Ant-TNF-alpha Biologic Drugs for the Induction and Maintenance of Remission in Inflammatory Crohn’s Disease. This reference was previously noted in blog (with a link) AGA Guidelines for the Use of Thiopurines and Anti  – gutsandgrowt.  The print version does have a nice algorithm (pg 1463).  The accompanying technical review: Gastroenterol 2013; 145: 1464-78.

8. BMJ 2013;347:f6633. Free full-text BMJ article PDF. (Thanks to Mike Hart for this reference) From the abstract:  During 3 421 972 person years of follow-up, we documented 284 cases of Crohn’s disease and 363 cases of ulcerative colitis. The risk of Crohn’s disease was inversely associated with physical activity (P for trend 0.02). Compared with women in the lowest fifth of physical activity, the multivariate adjusted hazard ratio of Crohn’s disease among women in the highest fifth of physical activity was 0.64 (95% confidence interval 0.44 to 0.94). Active women with at least 27 metabolic equivalent task (MET) hours per week of physical activity had a 44% reduction (hazard ratio 0.56, 95% confidence interval 0.37 to 0.84) in risk of developing Crohn’s disease compared with sedentary women with ❤ MET h/wk. Physical activity was not associated with risk of ulcerative colitis (P for trend 0.46). The absolute risk of ulcerative colitis and Crohn’s disease among women in the highest fifth of physical activity was 8 and 6 events per 100 000 person years compared with 11 and 16 events per 100 000 person years among women in the lowest fifth of physical activity, respectively. Age, smoking, body mass index, and cohort did not significantly modify the association between physical activity and risk of ulcerative colitis or Crohn’s disease (all P for interaction >0.35). Conclusion In two large prospective cohorts of US women, physical activity was inversely associated with risk of Crohn’s disease but not of ulcerative colitis.

Comment: While physical activity may directly reduce the risk of Crohn’s disease, it could also be an epiphenomenon of another unmeasured variable (eg. dietary habits) that modifies this risk.

Related blog post:

Understanding IBD Therapy Risks -A Good Link | gutsandgrowth  Provides link to useful 6-minute internet video for families.

IBD Update 2014 (part 1)

A number of recent articles that may be helpful for clinicians who help patients with inflammatory bowel disease.

1. Inflamm Bowel Dis 2013; 19: 2778-86.  “The Incidence and Predictors of Lupus-Like Reaction in Patients with IBD treated with Anti-TNF therapies.”  Key result: 20 of 289 (6.9%) developed lupus-like reactions (LLRs).  Female gender and IBD-unclassified were more prevalent in this group.  Clinical features included arthropathy (100%); fatigue and dermatitis were common.  All tested positive for ANA, 16 of 20 also had anti-dsDNA.  LLRs resolved with cessation of culprit agent and steroids.  Only one patient had recurrence who had switched to an alternative anti-TNF.

2. Inflamm Bowel Dis 2013; 19: 2753-62. This phase 3, randomized open-label multicenter study enrolled 60 children and provided data regarding infliximab pharmacokinetics in patients with moderate-to-severe ulcerative colitis.  The findings indicate that infliximab exposure-response is similar to adult patients.  At week 8, those with higher serum infliximab levels (≥41.1 mcg/mL) had higher efficacy (response 92.9%, remission 64.3%) compared with those with a lower levels <18.1 mcg/mL (response 53.9%, remission 30.8%).  Trough levels (at week 30) for q8 week-dosing was 1.9 mcg/mL compared with 0.8 mcg/mL for q12 week-dosing.

3. Inflamm Bowel Dis 2013; 19: 2744-52. A lot of pediatric IBD patients are colonized with Clostridium difficile.  In this prospective study of 85 outpatient IBD pediatric patients and 78 age-matched controls, asymptomatic C difficile carriage was noted in 17% of IBD patients compared with 3% of controls.  Use of proton pump inhibitors was associated with an increased carriage rate.

4. Inflamm Bowel Dis 2013; 19: 2937-48.  Excellent review article regarding fertility and pregnancy for women with IBD.  This review includes a discussion about the timing of pregnancy with regard to remission, effects of surgery and medications, acceptable radiology testing in pregnant patients, and issues regarding delivery.

Malignancy Risk with Thiopurines

Based on a large retrospective, nationwide cohort study, it has been estimated that patients with ulcerative colitis have a 4-fold increase in the risk of lymphoma compared with patients who have not been treated with thiopurines (Gastroenterol 2013; 145: 1007-15).  While this study enrolled data from 36,891 patients followed for a median of 6.7 years, this study should not be interpreted in isolation.  The editorial (pages 927-30) provides some important context.

Besides the risk of lymphoma in patients treated with the thiopurines, the editorial briefly states the potential for life-threatening infections, primarily varicella and hemophagocytic lymphohistiocytosis which may complicate primary EBV infection.  The latter is much more common in younger patients.

With regard to malignancy, besides lymphoma, thiopurines also increase the frequency of nonmelanoma skin cancer.  Since these are not life-threatening, in many patients the risk of lymphoma is “the major limiting factor for the prolonged use of thiopurines.”  Furthermore, the risk of lymphoma may increase relative to treatment duration according to the above-referenced study. The editorial notes that there are three types of lymphoma to be considered:

  1. Posttransplant-like lymphoma associated with EBV seropositivity. Absolute risk in all IBD patients ~ 1 per 1000 patient-years.  All EBV-seropositive patients are at risk.
  2. Early post-mononucleosis lymphomas. Absolute risk in all IBD patients ~0.1 per 1000 patient-years; however, the risk in young men who are seronegative for EBV (<35 years) is ~3 per 1000 patient-years.
  3. Hepatosplenic T-cell lymphomas.  Absolute risk in all IBD in all IBD patients ~0.05 per 1000 patient-years; again, in young patients (mostly men) the risk is ~0.1 per 1000 patient-years.

The second and third types of lymphomas can be reduced by limiting thiopurines in young men.

Despite the risks posed by thiopurines, the overall benefit-risk balance needs to consider the fact that the risk of colorectal cancer “is markedly reduced in patients with long-standing extensive colitis exposed to thiopurines.”  Thus, the lowered risk of colorectal cancer “may outweigh the excess risk of lymphoma.”

Also, in considering thiopurines:

Inflamm Bowel Dis 2013; 19: 2801-08.  “Thiopurines are Associated with a Reduction in Surgical Re-resections in Patient’s with Crohn’s Disease.”  This study was a retrospective review of 567 patients of whom 237 (41.8%) developed a surgical recurrence after a median of 70 months.  Taking thiopurine was associated with a hazard ratio of 0.51.  Due to small numbers, the results with anti-TNF therapy was not conclusive, but “seems promising as well.”

Related blog posts:

Predicting Remission in Pediatric Ulcerative Colitis

Trying to offer realistic information to families on the long-term success of infliximab (Remicade) for pediatric ulcerative colitis has been difficult due to a limited amount of data.  In addition, many studies have a number of limitations which can make it difficult to extrapolate to a less-selected population (According to the study which you would never qualify for ).

A recent post hoc analysis (Clin Gastroenterol Hepatol 2013; 11: 1460-65) from 51 children (age 6-17 years) provides some insight into this issue.  The authors used data collected prospectively during the T72 clinical trial (Clin Gastroenterol Hepatol; 10: 391-99 -reviewed in blog post: Infliximab for children with Ulcerative Colitis | gutsandgrowth).

Results:

  • Week 8 PUCAI scores best predicted which patients would be in steroid-free remission after 1 year of treatment: 9 of 17 (53%) with scores <10 points were in sustained remission compare with 4 of 20 (25%) with scores ≥10.
  • Week 8 PUCAI outperformed mucosal healing in predicting remission.

Key points:

  • PUCAI may have outperformed mucosal healing because the latter can lag behind clinical response.  Furthermore, mucosal healing is more subjective with less interobserver reliability.
  • In patients with known inflammatory bowel disease, endoscopic assessment remains important in several situations: condition or reason for symptoms is in question (eg. exclude irritable bowel symptoms or medication-induced symptoms), acute severe colitis not responding to 3-day treatment with intravenous steroids to exclude superinfection, and to assess mucosa before major treatment changes “such as when starting or stopping biologics and before referral for colectomy.”

Related blog posts: