OBJECTIVES
Population-based data on risk factors and protective factors for colorectal dysplasia and cancer in patients with inflammatory bowel disease (IBD) are sparse. We conducted a nested case–control study of such factors in two well-described IBD cohorts from Copenhagen County, Denmark and Olmsted County, Minnesota.
METHODS
Forty-three neoplasia cases were matched on six criteria to 1–3 controls (N = 102). Medical records were scrutinized for demographic and clinical data. For each variable, the odds of neoplasia were estimated using conditional logistic regression.
RESULTS
Primary sclerosing cholangitis (PSC) (odds ratio [OR] 6.9, 95% confidence interval [CI] 1.2–40), percentage of disease course with clinically active disease (OR [per 5% increase] 1.2, 95% CI 0.996–1.4), and ≥1 yr of continuous symptoms (OR 3.2, 95% CI 1.2–8.6) were associated with neoplasia, whereas a borderline association with median number of small-bowel x-rays (OR 1.3, 95% CI 0.96–1.6) was observed. We did not observe a protective effect of frequency of physician visits (OR 1.4, 95% CI 0.96–2.0), number of colonoscopies (OR 1.4, 95% CI 1.0–2.1), cumulative dose of sulfasalazine (OR [per 1,000 g] 1.1, 95% CI 1.0–1.3) and mesalamine (OR [per 1,000 g] 1.3, 95% CI 0.9–1.9), or partial intestinal resections (OR 1.5, 95% CI 0.3–7.1).
CONCLUSIONS
Subgroups of IBD patients—those with PSC, severe long-standing disease, and exposure to x-ray—were at greater risk of colorectal neoplasia. The protective effect of close follow-up, colonoscopy, and treatment with 5-aminosalicylates was questionable.
