Abstract
Introduction The risk of inflammatory bowel disease-associated colorectal cancer (IBD-CRC) is known to increase with primary sclerosing cholangitis (PSC) and a family history of CRC. However, the impact of comorbidities such as liver disease, obesity, diabetes, chronic lung, heart, and renal disease, and psychiatric illness on the risk of IBD-CRC remains unclear. We evaluated the effect of these comorbidities on the risk of IBD-CRC. Methods A retrospective review from 2009 to 2014 was conducted using the National Inpatient Sample data for adults 18 years and older. Patients with IBD (360,892), of whom 2,831 had CRC were identified using the International Classification of Diseases, Ninth Revision codes (ICD-9). Data on comorbidities were also obtained. Adjusted odds ratios (aOR) and confidence intervals (CI) were computed via logistic regression to evaluate the effect of comorbidities on the risk of IBD-CRC; the p-value was set at <0.05. Results The mean age of IBD patients in this study was 52.36±0.03. A majority of the patients with IBD-CRC were white and were significantly older compared to those without cancer (60 vs 52 years, p<0.05). The risk of colon cancer in IBD was increased by having a non-cholestatic liver disease (aOR 1.51, CI 1.23-1.86, p<0.01). Also, patients younger than 50 years with liver disease were at an increased risk of IBD-associated colon cancer in comparison to older patients (aOR 1.83 vs 1.34, p<0.05). Notably, diabetes, chronic pulmonary disease, renal failure, psychiatric illnesses, and rheumatoid diseases, were inversely associated with the risk of IBD-CRC (p<0.05). After stratifying by IBD subtypes, non-cholestatic liver disease was still independently associated with a higher risk for colon cancer in patients with ulcerative colitis or Crohn's disease (ulcerative colitis: aOR 1.43, CI 1.08-1.89; Crohn's disease: aOR 1.46, CI 1.10-2.00). Conclusions Patients with IBD who have non-cholestatic liver disease might have a higher risk for colon cancer, even at a younger age. These patients may require close colon cancer surveillance.