Risk Factors for Lymphoma in Patients with Inflammatory Bowel Disease: A Case-control Study

Background:Subgroups of patients with inflammatory bowel disease (IBD) may have an increased risk of developing lymphoma. We sought to identify factors that were associated with lymphoma in patients with IBD.Methods:Cases and controls were identified through a centralized diagnostic index. We identified 80 adult patients with IBD who developed lymphoma between 1980 and 2009. For each case, 2 controls were matched for subtype of IBD, geographic location, and length of follow-up. Conditional logistical regression was used to assess associations between risk factors and the development of lymphoma.Results:Sixty patients were males (75%) versus 77 controls (48%). Median age at index date was 59 years for cases and 42 years for controls. Twenty patients (25%) and 23 controls (14%) were receiving immunosuppressive medications at the index date. Four patients (5%) and 6 controls (4%) were receiving anti-tumor necrosis factor agents at the index date. In multiple variable analysis, age per decade (odds ratio, 1.83; 95% confidence interval, 1.37-2.43), male gender (odds ratio, 4.05; 95% confidence interval, 1.82-9.02) and immunosuppressive exposure at the index date (odds ratio, 4.20; 95% confidence interval, 1.35-13.11) were significantly associated with increased odds of developing lymphoma. Disease severity and use of anti-tumor necrosis factor agents were not independently associated with developing lymphoma. When testing was performed on patients exposed to immunosuppressive or anti-tumor necrosis factor medications, Epstein-Barr virus was identified 75% of the time.Conclusions:In this case-control study, increasing age, male gender, and use of immunosuppressive medications were associated with an increased risk of lymphoma in patients with IBD.