Inflammatory bowel disease on the rise in specific populations

Jun 1 2009

Researchers are making great strides in understanding the development and treatment of inflammatory bowel disease, a chronic inflammatory condition of the digestive tract that affects more than a half million Americans, according to several studies being presented at Digestive Disease Week® 2009 (DDW®). DDW is the largest international gathering of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

Inflammatory bowel disease (IBD) is a term that refers to both ulcerative colitis and Crohn's disease. Ulcerative colitis is a disease of the colon in which inflammation of the lining of the large intestine occurs. Crohn's disease causes inflammation of the lining and wall of the large and/or small intestine. When inflamed, the lining of the intestinal wall is red and swollen, becomes ulcerated, and bleeds.

"There is still a lot we don't know about the natural history and course of inflammatory bowel disease," said Sunanda V. Kane, MD, AGAF, Mayo Clinic, Rochester. "Work in the epidemiology of these conditions suggests an increase in incidence, making the study of its genesis and treatment that much more important."

Patients with IBD Are Exposed to Potentially Serious Excesses of Ionizing Radiation (Abstract #650)

Patients with inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC) have frequent radiologic examinations and may be at risk for excessive radiation exposure. These gastrointestinal conditions often affect young people, who are then frequently examined with a CT scan to assess for complications or the activity of their disease. Investigators sought to discover how many radiological procedures patients underwent and to how much ionizing radiation they were exposed.

Frequency and age are key factors in the question of whether too much radiation exposure is problematic in part because CD is a chronic, incurable disease. The patient who is diagnosed at a young age may receive multiple imaging tests, and the younger a patient is when first exposed to radiation, the more at risk they are of having damage to their DNA.

Investigators identified approximately 500 patients with CD and UC to study the number and type of radiologic tests taken over a five-year period to learn how many scans or X-rays patients had been exposed to in an effort to measure radiation exposure rates. They found that patients with CD were exposed to twice as much radiation as patients with UC. Lead researcher Karen Kroeker, MD, fellow with the division of gastroenterology at the University of Alberta, said this may be because CD often leads to complications, such as intestinal obstruction and/or fistula that require radiologic tests for their diagnosis.

Dr. Kroeker found that the majority of radiation - about 66 percent to 75 percent - was generated from CT scans, a finding she says is attributable to the fact that CT scans have become readily available in most hospitals over the last 20 years and are excellent tools for diagnosing the complications associated with IBD. Almost every hospital has a CT scanner, which is beneficial because they provide very good information, said Dr. Kroeker, fellow, division of gastroenterology at the University of Alberta. But CT scans invariably produce more radiation than a simple X-ray or MRI. However, Kroeker adds that X-rays and MRIs are generally less valuable than CT scans in diagnosing the complications associate with IBD.

"We know that CT scans are excellent diagnostic tests, however they do have the potential risk of exposure to ionizing radiation. Physicians need to test, explore and learn about new and better diagnostic modalities, such as intestinal ultrasound, that could eventually replace CT scan," said Dr. Kroeker. "In addition, physicians need to be aware of how many CT scans their patients have been exposed to so that they can determine the risk of additional CT scans."

Dr. Kroeker will present these data on Tuesday, June 2 at 10:30 a.m. CDT in S406A, McCormick Place.

A Randomized Controlled Trial of Growth Hormone in Active Pediatric Crohn's Disease (Abstract #74)

Administering growth hormone to pediatric Crohn's disease (CD) patients may not only reverse growth failure, but may also be effective in reducing symptoms and improving disease activity.

Researchers at Cincinnati Children's Hospital Medical Center sought to determine whether previous success in improving symptoms with growth hormone in adult CD patients could be replicated for pediatric CD patients along with an improvement in growth failure. As many as 80 percent of children with CD experience growth failure, low muscle build up and weakened bones as a result of the disease. The best window for "catch-up growth" is before age 12.

Twenty children, ranging in age from seven to 18, were enrolled in the study, with 10 receiving the growth hormone and 10 in the control group. Investigators found that after three months, the disease in two-thirds of the patients receiving the growth hormone went into remission. After one year, study participants continuing to receive the growth hormone also achieved a significant improvement in growth. For most, this resulted in "catch-up" towards the height they would have been predicted to reach prior to becoming ill.

"Our results are very encouraging," said Lee Denson, MD, director of the Schubert-Martin Inflammatory Bowel Disease Center at Cincinnati Children's and associate professor of pediatrics at the University of Cincinnati College of Medicine. "With minimal side effects, including the burden of receiving daily injections and mild joint pain, growth hormone holds tremendous potential for improving both symptoms and growth in pediatric CD patients."

Dr. Denson, who conducted the study along with David Klein, MD, PhD, of the division of endocrinology at Cincinnati Children's, said that while the results of this study are encouraging, a larger, multi-center study would need to be conducted in order to determine which children with CD might receive the most benefit from growth hormone.

Dr. Denson will present these data on Sunday, May 31 at 8:45 a.m. CDT in S105, McCormick Place.

Increased Risk of Inflammatory Bowel Disease After Salmonella or Campylobacter Gastroenteritis: A Population-Based Study (Abstract #80)

Researchers in Denmark have discovered a link between inflammatory bowel disease (IBD) and an initial bacterial infection with either salmonella or campylobacter gastroenteritis, an important step in understanding the development of IBD that may help explain the increasing incidence of IBD over the past decade.

Denmark's system of tracking its citizens with individual identification numbers allowed researchers to examine patient interaction with the health-care system over a 15 year period. Investigators examined how many patients in a control group would develop IBD and compared them with those who have been exposed to bacteria in the past. They found that over 15 years, three times as many patients who had been exposed to bacteria later developed IBD as those who had not been exposed.

"This is the first time we are able to make such a clear association with an initial exposure to bacteria and subsequent development of IBD in the long term," said Nielsen Henrik, MD, professor of infectious diseases at Aalborg Hospital in Denmark. "Our research has important implications for food safety and disease prevention. If we can reduce and prevent the spread of food bacteria and infections, we may reduce or even largely eliminate IBD in the long term."

Dr. Nielsen is hopeful that further research will go beyond the association between bacteria exposure and IBD established in his study and attempt to prove causality by studying in detail the biology of individual patients.

Dr. Nielsen will present these data on Sunday, May 31 at 8:30 a.m. CDT in S103ABC, McCormick Place.

Associated of Methicillin-Resistant Staph Aureus (MRSA) with Higher Mortality Among Hospitalized IBD Patients (Abstract #S1103)

A new study suggests that patients with inflammatory bowel disease (IBD) who require frequent hospitalization and medications that weaken their immune systems may be more susceptible to MRSA (Methicillin-resistant Staph aureus) infection and other hospital-acquired infections.

"Our study showed that IBD patients with MRSA are four times as likely to die in the hospital," said lead investigator Geoffrey Nguyen, MD, PhD, assistant professor of medicine, Mount Sinai Hospital (University of Toronto) and Johns Hopkins School of Medicine. "But patients with other GI conditions who are infected with MRSA were half as likely to die."

Researchers looked at cases of IBD patients between 1998 and 2004 and found that hospitalized patients with IBD were 42 percent more likely to acquire MRSA than patients with other gastrointestinal illnesses. Patients with Crohn's disease were especially susceptible, possibly because their medication can weaken the immune system.

Dr. Nguyen cautioned that the study does not necessarily mean that MRSA is the cause of increased mortality among IBD patients, only that the possible relationship should be studied further. Also, the data looked at in this study were retrospective; investigators did not have information on the exact date and time of death, nor the exact cause of death. In subsequent research they plan to follow IBD patients who contract MRSA and track whether their cases are fatal. "Based on what this data seems to show, we think IBD patients are more susceptible to MRSA but we need further prospective studies to confirm this," said Dr. Nguyen.

The study also looked at other factors that could allow for the discrepancy and found that IBD patients with C.difficile infection were at double the risk of contracting MRSA. They also found differences in rate of infection depending on age - the older the patients were, the more susceptible they may have been. There also seemed to be increased risk associated with patients receiving Medicare or Medicaid, a factor which Dr. Nguyen said should be looked at more closely.

Dr. Nguyen will present these data on Sunday, May 31, 2009 at 8 a.m. CDT in South Hall, McCormick Place.

The Changing Pattern of Crohn's Disease Incidence According to Age in Northern France: A Constant Increase in the 0-19 Years Age Group (Abstract #114)

A population-based study of residents in northern France finds that the incidence of Crohn's disease (CD) is on the rise, most dramatically among young people less than 19 years of age. The findings raise a number of questions about the likely causes of the increase, which the investigators say could be related to environmental factors.

Investigators from the EPIMAD registry in France tracked rates of CD among nearly six million patients in northern France between 1988 and 2005. They found that the incidence of CD among all patients increased 20.7 percent but that rates had stabilized 10 years into the study. Among young people less than 19 years of age however, the incidence of CD increased linearly by 48.5 percent.

The cause of the increased incidence of CD among young people is unknown, but investigators say aggravating factors like environmental pollution and changes in diet or smoking habits could be culprits.

"Since we now know that CD disproportionately affects young people, future studies to uncover its cause should focus on this age group," said Guillaume Savoye, MD, EPIMAD registry and department of gastroenterology, University Hospital, Rouen, France.

Dr. Savoye will present these data on Sunday, May 31 at 11:30 a.m. CDT in S502, McCormick Place.