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5-Aminosalicylic Acid and Risk of Colorectal Polyps in Patients with Inflammatory Bowel Disease: Presented at UEGW

By Chris Berrie

COPENHAGEN, DENMARK -- October 21, 2005 -- Patients with irritable bowel disease (IBD) have a marked reduction in the risk of developing colorectal polyps if they are treated with 5-acetylsalicylic acid (5-ASA), according to a retrospective case-control study presented at the 13^th United European Gastroenterology Week (UEGW).

Polypoid dysplasia is a critical point in the pathway to colorectal cancer in patients with IBD, said William Blumentals, PhD, Co-Investigator and Senior Scientist, Epidemiology, Procter & Gamble Pharmaceuticals, Mason, Ohio, United States, during his presentation here on here October 18^th.

To determine the impact of 5-ASAs prophylaxis on polyp development in these patients, Dr. Blumentals and colleagues pooled data from the Ingenix Lab/Rx Database(TM) relating to all first polyp diagnoses in patients 18 years and older between 1 January, 2001 and 30 April, 2004.

Polyp cases were validated by the database examination for a colonoscopy procedure within 60 days of the polyp diagnosis.

For every positive polyp case, the researchers selected randomly 10 control patients with continuous enrolment in the same or the prior calendar year. They excluded patients with a record of polyps, colorectal cancer or bowel surgery. Controls were age and gender matched to polyp cases with reference to the polyp index date.

To determine the role of 5-ASA therapy on IBD status, the researchers examined the database for 5-ASA therapy during the 12-month period prior to the polyp diagnosis dates.

The relative risk associated with each patient group was calculated through conditional logistics regression analysis using crude odds ratios (cORs), which in some cases were fully adjusted for patient age, gender, selected medication and medical history characteristics.

The 51,919 polyp cases and 519,190 controls had a prevalence of IBD of 0.78% and 0.19%, respectively. This provided a significant cOR of 4.06 (95% confidence interval [CI], 3.61-4.55), which shows that patients with polyps had a 4-times greater prevalence of IBD than controls.

The corresponding data for the ulcerative colitis and Crohn's disease patients within the IBD cases were: for UC, 254 (0.49%) versus 583 (0.11%); and for Crohn's disease, 180 (0.35%) versus 497 (0.10%).

Drug use for the polyp and control groups was broken down into 5-ASAs (59.1% vs. 51.1%), nonsteroidal anti-inflammatory drugs (21.4% vs. 27.5%), glucocorticosteroids (35.0% vs. 26.2%) and immunomodulators (13.8% vs. 12.9%). This indicated that polyp cases used more 5-ASA and glucocorticosteroids.

When the researchers adjusted 5-ASA data for the specific medications used, the increased use was only significant for mesalamine.

To analyse this further, mesalamine use in the 12 months prior to the polyp index dates was determined as a measure of the number of prescriptions issued for mesalamine. With a single prescription used as reference, in ulcerative colitis patients in the polyp and control groups the issuing of 2 to 5 prescriptions for mesalamine demonstrated a reduced, but non-significant, cOR, which also remained non-significant when fully adjusted.

The suggestion of a protective role for mesalamine on polyp formation in patients with ulcerative colitis did, however, reach significance in Crohn's disease patients. This demonstrated that the issuing of 2 to 5 prescriptions for mesalamine in the Crohn's disease population resulted in a 57% reduction in the risk of polyp development.

Dr. Blumentals concluded that as this case-control study was able to demonstrate a higher risk of polyps in IBD patients and a marked reduction in the risk of developing polyps in the Crohn's disease patients receiving mesalamine, there is now the need to investigate in more detail the protective effect of 5-ASA on polyp development in IBD patients.

Procter & Gamble provided financial support for this study.


[Study title: 5-Aminosalicylic Acid Therapy and Risk of Colorectal Polyps among Patients with Inflammatory Bowel Disease: Results of a Case-Control Study. Abstract TUE-G-106]

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