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MRSA infection prevalent in inflammatory bowel disease; mortality rates high

Reuters Health • The Doctor's Channel Daily Newscast

CHICAGO (Reuters Health) – A Canadian study of patients with inflammatory bowel disease (IBD) shows that they are 42% more likely to acquire methicillin-resistant Staphylococcus aureus (MRSA) infections than are patients with other gastrointestinal illnesses, investigators announced here during the first full day of sessions at Digestive Disease Week 2009.

The evaluation of 7 years of data from the Nationwide Inpatient Sample, including 116,842 IBD admissions, was presented by Dr. Geoffrey C. Nguyen of the University of Toronto.

Dr. Nguyen reported the prevalence of MRSA infection increased from 1.6 cases per 1000 admissions to 3.8 cases per 1000 admissions between 1998 and 2004.

“This reflected an average 20% annual rise in odds of MRSA infection,” Dr. Nguyen announced at a news conference. “MRSA prevalence in IBD patients was higher in comparison to non-IBD GI inpatients,” with an adjusted odds ratio of 1.42.

The prevalence of MRSA was statistically equal in patients with Crohn’s disease and those with ulcerative colitis, at 2.7 and 2.5 cases per 1000, respectively.

In contrast, the prevalence of MRSA “was considerably higher among IBD patients who had coexisting C. difficile relative to those who did not,” Dr. Nguyen reported, at 6.6 cases per 1000 for IBD with C. difficile and 2.6 cases per 1000 for IBD without C. difficile infection.

Increasing age and IBD-related surgery during hospitalization had an adjusted OR of 2.11 for MRSA. Medicare and Medicaid insurance were also associated with increased likelihood MRSA infection, the Toronto researcher added. When these factors were controlled for, the adjusted OR for MRSA in IBD patients with C. difficile was 2.42.

“After adjustment for age, sex, comorbidity, health insurance, IBD-related surgery, and C. difficile infection, the presence of MRSA was associated with a four-fold higher in-hospital mortality relative to those without MRSA,” Dr. Nguyen said.

“This association of MRSA with mortality was higher in IBD patients than in non-IBD GI patients,” with an adjusted OR=2.43 for IBD compared with non-IBD status.

“IBD patients with MRSA also had a significantly longer length of stay than those without IBD, at 17.4 days versus 6.1 days, respectively,” Dr. Nguyen said.

“Patients with Crohn’s disease…are especially susceptible, possibly because they are often treated with an antibiotic for their condition and this may make them at increased risk for MRSA,” he commented.

“We also want to caution that the study does not necessarily mean that MRSA is a cause of increased mortality among IBD patients….We plan to conduct subsequent research to study IBD patients who contract MRSA and track their cases and see which ones are ‘fail’ cases and the actual proximal causes of death,” he told Reuters Health.

“I think the most important role for physicians is the control of infection at the hospital level.”