Category Archives: inflammatory bowel disease

Global increases in IBD incidence

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Two more studies have shown increasing incidence of pediatric inflammatory bowel disease.

First in Victoria, Australia (mostly Melbourne) (Inflamm Bowel Dis 2013; 19: 1-6).

Over a 60-year span (1950-2009), a retrospective review was undertaken of ulcerative colitis (UC) pediatric patients. In total, 342 children were diagnosed with UC. Key finding: The number of reported cases increased by 11-fold during the study period with a marked increase since 1990 (0.15 –>1.61/100,000).  In addition, recently diagnosed children have had more extensive disease.

Next in Spain (Inflamm Bowel Dis 2013; 19: 73-80).

This retrospective study from hospitals’ databases looked at the incidence between 1996-2009 in the pediatric population (<18 years).  A total of 2107 patients were identified: 1165 with Crohn’s disease, 788 ulcerative colitis, and 154 IBD unclassified. Median age at diagnosis was 12.3 years.  Key finding: in the last 14 years, pediatric IBD incidence has almost tripled (0.9 –>2.8/100,000).

Both of these studies have limitations related to large retrospective reviews in terms of potential problems with capturing all of the patients and the potential for misdiagnosis.  However, the trend is clear.  In addition, these studies show incidence rates comparable to several other Western studies.  The increasing incidence of IBD ‘argue for a common environmental factor in their pathogenesis.’  While interest has focused on microbial factors, the basis for this increased incidence currently remains elusive.

Related blog posts:

True red flags in recurrent abdominal pain

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For pediatricians and pediatric gastroenterologists alike, identifying which children need additional workup for recurrent abdominal pain (RAP) is facilitated by recognizing “red flags.”  “Red flags” are clinical features that indicate a higher likelihood of a nonfunctional disorder.  A recent study notes that reports of waking from sleep and joint pains do not distinguish functional from nonfunctional causes of RAP (J Pediatr 2013; 162: 783-7).

This study, performed between 2005 to 2008, had patients presenting to an outpatient pediatric gastroenterology clinic for RAP prospectively complete a detailed questionnaire. Data, though, was extracted retrospectively. In this population (n=606), 85% were Caucasian.  After their evaluation, patients with functional GI diseases (FGID, n=478) were compared with patients confirmed with Crohn’s disease (CD, n=128).  All FGIDs underwent biochemical testing, 41% had upper endoscopy, and 32% underwent colonoscopy.

Additional key findings:

  • Using a tree analysis, the cumulative sensitivity for Crohn’s disease was 54% with the presence of anemia, 78% when blood in stool was added to anemia, and 94% when weight loss was added as well.
  • FGID patients were more likely to report stress and headaches, more likely to have family history of FGID, and less likely to have anemia, hematochezia, or growth issues.
  • FGID patients were more likely to experience vomiting.

The sensitivity and specificity of these symptoms/signs will vary based on the population.  For a general pediatric clinic, it is likely that the sensitivity of these red flags would remain high; the specificity would likely be lower than in a pediatric gastroenterology office due to the increased prevalence of functional diseases in the general pediatric setting.

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Paris Classification of Pediatric Crohn’s Disease

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A recent study described the phenotypic results of a prospective, web-based registry of new-onset pediatric inflammatory bowel disease (IBD) in 17 European countries and Israel (Inflamm Bowel Dis 2013; 19: 378-85).

The EUROKIDS Registry included 582 pediatric Crohn’s Disease (CD) patients classified according to Paris classification:

  • 16% with L1 involvement of the terminal ileum only
  • 27% with L2 colonic involvement only (more common in younger children)
  • 53% with L3 involvement of the ileum and colon
  • 4% with L4 isolated upper GI disease.  Upper tract disease can be further subdivided into L4A esophagogastric disease and L4B jejunal/proximal ileal disease.
  • *Upper GI disease can coexist with L1, L2 or L3.  In this study, 34 (6%) had esophageal involvement, 102 (18%) had gastric involvement, and 100 (17%) had duodenal involvement.
  • In this study, 165 of the 507 patients did not undergo small bowel imaging. Of those who did, 64% had small bowel follow-through, 38% had MRI, 6% CT, and 5% video capsule.

Other findings:

  • Perianal disease (e.g.. fistula or abscess) noted in 9% at diagnosis.
  • Granulomas were found in 43% of patients who had biopsies from at least 10 segments of the GI tract
  • 82% of CD patients had nonstricturing, nonpenetrating disease (B1), 12% had stricturing disease (B2) and 5% had penetrating disease (B3).  2% had both stricturing and penetrating disease.
  • Extraintestinal manifestations were seen in 20% of the study population.
  • The authors estimated that the diagnostic yield of upper endoscopy  in the workup for pediatric IBD was  7.5% and for intubation of the ileum/ileoscopy 13%.

Study limitations included a selection bias of centers and pediatric gastroenterologists with a special interest in IBD.  Also, in this registry, older adolescents are underrepresented. In about one-third of the centers, patients older than 15 years are seen primarily by adult gastroenterologists.

Don’t Fix What’s Not Broken

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A recent study provides information about elective switching from infliximab (IFX) to adalimumab (ADA) in stable Crohn’s disease (CD) (Inflamm Bowel Dis 2013; 19: 761-66).  As a practical matter, patients and families inquire about switching therapy due to potential convenience and flexibility.  Thus far, there is little data to guide clinicians.  As such, the authors explored this question by designing an open-label study which would allow enrollment of any patients who had stable disease for >6 months (Harvey-Bradshaw Index ≤ 8) on IFX therapy.

In total, 29 patients with CD were enrolled with an average age of 39.  Twelve had previous resections.

Key results:

  • 21 patients (72%) were able to remain on ADA at 54 weeks.  8 patients discontinued ADA due to disease activity (n=3), side effects (n=4), or other symptoms (n=1).
  • 4 patients were restarted on IFX therapy; 1 required dose intensification.
  • At 54 weeks, 13 patients indicated a preference for IFX due to efficacy (n=9) or safety profile (n=4).  12 patients indicated a preference for ADA.  4 patients had no preference.

The authors state that a recommendation to avoid elective switching.  In their study, 28% were not able to be maintained on ADA therapy, more patients preferred IFX after experiencing both therapies, and switching back to IFX has been associated (in some) with reduced efficacy.  The main concern with an elective switch is the potential loss of response with very limited therapeutic alternatives.

The authors note that their study showed better results with an elective change than a previous study (the SWITCH trial, n=73).  In the SWITCH trial, “elective switch from IFX to ADA in patients with stable CD led to 47% of patients requiring dose intensification or interruption of treatment” in the ADA arm compared with 16% of patients who continued IFX therapy.  (Adalimumab in Crohn’s Disease Controlled by Infliximab)

The better outcomes in the current trial may have been due to selection of patients with milder disease and the more frequent use of concomitant immunosuppression.  In the current trial, 52% had concomitant immunosuppression (48% thiopurine, 4% methotrexate); in contrast, only 17% received concomitant immunosuppression in the SWITCH trial.  Another important difference was that the patients in the current trial received 160-80 loading doses rather than 80-40 induction.  Also, the trial designs were different.  The current trial enrolled patients without randomization; in contrast, the SWITCH trial randomized some patients to continue IFX and others to change to ADA therapy.

Related reference:

  • -Gut 2012; 61: 229-34. SWITCH trial.

Related blog references:

Budesonide for Ulcerative Colitis

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Budesonide (Uceris) has been formulated with the MMX delivery technology and now has been FDA approved for mild to moderate ulcerative colitis in adults.  The potential advantage of budesonide compared with conventional corticosteroids is for targeting anti-inflammatory activity to the colon with less systemic side effects.  The potential downside includes the high cost.  According to one website (see below), the average wholesale cost is just below $1500 per month.  In addition, only a minority of individuals responded to budesonide in published studies:

Induction of Remission in Studies 1 and 2 (reference below)

Treatment Group

Study 1 n/N (%)

Study 2 n/N (%)

UCERIS 9 mg

22/123 (17.9)

19/109 (17.4)

UCERIS 6 mg

16/121 (13.2)

9/109 (8.3)

Reference Arm*

15/124 (12.1)

13/103 (12.6)

Placebo

9/121 (7.4)

4/89 (4.5)

Treatment Difference between UCERIS 9 mg and Placebo (95% CI)†

10.4% (2.2%, 18.7%)

12.9% (4.6%, 21.3%)

Data for budesonide for pediatric patients with ulcerative colitis is not available.

How effective are aminosalicylates for pediatric UC?

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In a prospective, multicenter, inception cohort study (JPGN 2013; 56: 12-18) with 213 newly diagnosed ulcerative colitis (UC) patients, oral aminosalicylate (5-ASA) therapy was effective in 86 (40%).  That is, 40% were considered to be in corticosteroid-free remission at 1 year using 5-ASA as primary maintenance therapy.

This study took place between 2002-2010.  Of 1669 children enrolled in the registry from 32 sites, 440 (26%) were diagnosed with UC.  Of this group, 353 had followup >1 year and 213 met inclusion/exclusion criteria; all patients had to be treated with only 5-ASA or corticosteroids in the initial 30 days following diagnosis.  Most of those excluded had other therapies.  Among those with primary oral 5-ASA treatment, only 98 started treatment without a steroid induction.

Some interesting aspects of the study group:

  • 82% had pancolitis
  • 62% had moderate/severe disease at diagnosis based on physician global assessment
  • No laboratory or clinical features were associated with a higher likelihood of response
  • Mean daily dosage of 5-ASA was 52 mg/kg/day; 23% had a dose >60 mg/kg/day

The authors note that improved patient adherence and possibly higher 5-ASA dosing schedules may improve response to 5-ASA treatment.

Related blog entry:

Once daily Mesalamine | gutsandgrowth

A-OK for Accutane

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Another article has reaffirmed that isotretinoin (Accutane) does not increase the risk of IBD (JAMA Dermatol 2013; 149: 216-20).  Thanks to Mike Hart for this reference. However, this data will not reverse the millions of dollars that have been lost in litigation (Isotretinoin – Wikipedia, the free encyclopedia).

Using a large U.S. health claims database (68 million patients), the authors examined women ages 18-46 years who had received at least one oral contraceptive prescription between 2001-2009.  For each patient with IBD, 20 controls were identified in a nested case-control study design.

In total, 2159 IBD cases (1056 UC, 1103 CD) were matched with 43,180 controls.  Only 10 patients with IBD were exposed to isotretinoin compared with 191 controls.  The adjusted relative risk (RR) for IBD was 0.99; for ulcerative colitis the RR was 1.1 (confidence intervals 0.44-2.7) and for Crohn’s disease the RR was 0.91 (confidence interval 0.91).  For the meta-analysis which was a secondary part of this study, the RR for IBD with 5 studies was 0.94.

Conclusion: The study results do not suggest an increase risk of IBD with isotretinoin use.

Why did previous studies suggest a link between IBD and isotretinoin? The authors note that this is the first study to adjust for two main confounders, mainly a diagnosis of acne and use of oral tetracycline antibiotics.  Oral antibiotics, including tetracyclines, have been associated with IBD previously.  In addition, the design limits the confounding of contraceptive usage.

Limitations of this study:

  • Only women were studied; however, there are no known biologic factors that would make isotretinoin more problematic for males.
  • Other risk factors were not examined: smoking, ethnicity, diet, IBD family history

Additional references:

  • -Am J Gastroenterol 2009; 104: 2774-78.  Population-based study in Winnipeg, <40yrs.  n=1960 cases and 19,419 controls.  No differences in the proportions of IBD cases taking isotretinoin vs controls.  1.2% of IBD cases received isotretinoin prior to IBD diagnosis (n=25) compared with 1.1% of controls (n=213).  Mean # of days prior to IBD dx was 1102.  Thus, isotretinoin unlikely to be causally-associated with idiopathic IBD.
  • -IBD 2009; 12: Supplement -abstract O -0002  Increased risk of UC after isotretinoin.  OR 4.36 for developing UC
  • -Am J Gastroenterol 2009; 104: 2387-93.  7 country study found no causal association between isotretinoin & colitis.

Thiopurine Metabolite Testing -NASPGHAN Consensus Recommendations

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The inflammatory bowel disease committee of NASPGHAN has published a review and recommendations for the use of thiopurine metabolite testing (JPGN 2013; 56: 333-40).

The effectiveness of thiopurines is reviewed with a few key points:

  • Cochrane reviews have shown that azathioprine and 6-mercaptopurine are effective in inducing remission in Crohn’s disease.  For active disease the overall response rate has been reported as 54% compared with 33% for placebo.
  • For ulcerative colitis, a Cochrane analysis deemed the methodologic quality of 4 of the 6 studies as unsatisfactory and that all studies were small.  “The reviewers concluded that azathioprine may be effective treatment for patients with ulcerative colitis.”

The review covers the potential adverse effects of the thiopurines: myelosuppression, pancreatitis, elevated transaminases, susceptibility to infection, and malignancy.  The review suggests that the risk of non-Hodgkin lymphoma is probably increased up to 4-fold. Though, it is difficult to determine how much of the risk is truly due to the usage of thiopurines or other confounding factors.  The studies about the risk of non-melenoma skin cancer are not discussed.

Other covered topics: advantages of thiopurine metabolite testing (6-thioguanine [6-TGN] and 6-methylmercaptopurine[ 6-MMP]), potential disadvantages of metabolite testing (e.g.. cost), use of genotype versus phenotype (phenotypic testing is generally preferred), thiopurine metabolism, devising target levels, use of allopurinol, and misinterpretation of metabolite testing.

Specific Consensus Recommendations:

  • Obtain thiopurine methyltransferase (TPMT) testing prior to initiation of thiopurines.
  • Avoid use of thiopurines in individuals with extremely low TPMT activity or who are homozygous recessive for TPMT activity
  • TPMT testing does not predict all cases of leukopenia.  All individuals receiving thiopurines should have routine monitoring with CBCs.  “Most adverse effects from thiopurines are not directly related to 6-TGN or 6-MMP levels.”
  • Metabolite testing can help determine adherence to therapy
  • Metabolite testing may be helpful in guiding dose adjustment and/or adding allopurinol treatment
  • Routine and repetitive testing of metabolites is not recommended in patients who are doing well on an acceptable thiopurine dosage.

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Anti-TNFs and Pregnancy

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While pregnancy does not occur commonly while patients are in a pediatric gastroenterology practice, the possibility of becoming pregnant certainly influences our choice of medications.  With inflammatory bowel disease (IBD), I rarely recommend methotrexate in young women due to its teratogenicity.  With regard to the anti-TNF agents, there is less data available.   Two recent studies add some insight into this issue.

The first study ((Clin Gastroenterol Hepatol 2013; 11: 318-21) followed 31 pregnancies in 28 women with IBD (2006-2011).  18 patients received infliximab (IFX) and 13 adalimumab (ADA).  Most were receiving lower doses; only one IFX patient was receiving 10 mg/kg/dose and only two ADA patients were receiving weekly dosing.  Levels of anti-TNF agents were measured from cord blood from 18 newborns (12  IFX, 6 ADA).

Results:

  • 28 live births.  3 miscarriages (1 IFX, 2 ADA).  No congenital malformations were noted.
  • Mean cord IFX level was 6.4 mcg/mL.  A level of 2.8 mcg/mL was noted in the early discontinuation group –stopping 10 weeks prior to delivery .
  • Mean ADA level was 1.7 mcg/mL in five infants.  One infant had an undetectable level. All mothers had stopped ADA at gestational week 22.

In the second study (Clin Gastroenterol Hepat 2013; 11: 286-92) there were 31 pregnant patients. Anti-TNF treatment: Certolizumab (CZP) (n=10), IFX (n=11), ADA (n=10).  Serum levels were measured at birth in the mother, infant, and in cord blood. Then, levels were followed monthly until undetectable.  Among women receiving IFX, two were receiving 10 mg/kg/dose.  Women were identified through the Crohn’s Colitis Foundation of America Pregnancy IBD and Neonatal Outcomes (PIANO) Registry.

Results:

  • IFX was detectable for 2-7 months postpartum (median interval prior to delivery and last dose was 35 days).  Median IFX level in the cord was 160% that of the mother.
  • ADA was detectable for at least 11 weeks in infant’s circulation (median interval prior to delivery and last dose was 5.5 weeks). Median ADA in the cord was 153% of the mother.
  • Median CZP in the cord was 3.9% that of the mother.
  • No congenital anomalies or complications were reported in any of the infants.

Bottomline from these studies:

Stopping these drugs after the second trimester lowers the level of these medications in the infant.  This likely results in a lower likelihood of the infant developing an opportunistic infection but also results in a low risk for the mother of an IBD flareup.  Certolizumab pegol has very low levels of placenta transfer.

Related references:

  • -J Am Acad Dermatol 2011; 65: 870.  Death noted in infant whose mother took IFX after BCG vaccination.
  • -J Crohns Colitis 2011; 5: 555-8.  Low levels of IFX detected in infants from nursing mothers with IBD  (1/200th of the maternal level in serum 2 to 3 days after infusion).
  • -Clin Gastroenterol & Hep 2010; 8: 509. n=2377. Crohn dz assoc w prematurity but not birth defects.
  • -Gastroenterol 2003;124: 9-17. Safety of 6-MP in pregnancy. n=155, at least 1 pregnancy. No adverse effect noted.
  • -Clin Gastroenterol & Hepatology; 2006: 4: 1255.  Infliximab crosses placenta but was not detected breastmilk.

Early antibiotic use and the development of inflammatory bowel disease

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Another study adds weight to the idea that early antibiotic use may increase the risk of developing inflammatory bowel disease (IBD) (J Pediatr 2013; 162: 510-4).

Using a nested case-control design, the authors matched 2377 controls to 294 children with IBD in a population-based database from Manitoba, Canada.  Specifically, the authors looked at the frequency of otitis media diagnosis and the likelihood of subsequent IBD.  By age 5 years, 89% of IBD cases had at least one diagnosis of otitis media, compared with 82% of the controls.  Despite the high frequency in both groups, the authors determined that individuals with a diagnosis of otitis media before age 5 years were 2.8-fold more likely to be an IBD case.

Some of the strengths of this study included the fact that it was a population-based analysis dating back to 1984 and likely captured almost all pediatric IBD cases (<19 years).  Nearly all physicians in Manitoba submit billing claims to a single publicly funded source.  Due to the nature of administrative data, this eliminates recall bias.

However, administrative data have several limitations as well.  Other confounding conditions may have been present and not identified; this could include family history and autoimmune diseases.

The authors “suspect” that the linkage between otitis media and IBD relates to the usage of antibiotics and subsequent alterations of the intestinal microflora.  Otitis media may serve as a “sensitive proxy measure” of antibiotic use.  Also, as boys are more frequently treated for otitis media, this may relate to the generally higher incidence of pediatric IBD in males.

For anyone interested in the association between antibiotic exposure and IBD, this study is useful and provides a number of references as well.

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