Type II Diabetes Mellitus, A Risk Factor for Colonic Adenomas: 1506

Purpose: Type 2 diabetes mellitus and colorectal cancer are major causes of morbidity and mortality in the United States. Studies have demonstrated that patients with type 2 diabetes mellitus are associated with a 30-40% increased risk of colorectal cancer; however, the association between type 2 diabetes mellitus and risk of colonic adenomas has not been well studied. While it has been postulated that hyperinsulinemia may promote proliferation of adenomas through adenoma-carcinoma sequence; to our knowledge, no previous study has addressed the clinical presentation and behavior of adenomatous polyps in patients with type 2 diabetes mellitus compared to the general population. The aim of this study is to assess the outcomes of index screening colonoscopy between patients with type 2 diabetes mellitus and the average risk population. Methods: A retrospective chart review was performed of index colonoscopies in patients with type 2 diabetes mellitus and average risk population. The EPIC database at MetroHealth Medical Center was interrogated for all patients with index screening colonoscopies and those with a diagnosis of type 2 diabetes mellitus between January 2007 and January 2010. First screening colonoscopies were compared between 269 type 2 diabetic patients and 591 patients of average risk population. Data was evaluated for patient characteristics and colonoscopy outcomes. P-values were determined using SAS software and the chi square test. Statistical significance was determined as p<0.05. Results: A total of 860 patients who had undergone index screening colonoscopy were identified. Patient characteristics are shown in Table 1 and are comparable between the two groups. Table 2 reveals the colonoscopy outcomes between the diabetic and average risk population. Of note, the frequency of three or more adenomas, adenomas >1cm, mean number of polyps, and the proximal location of advanced adenomas were significantly greater compared to the average risk population.Table 1: Clinical characteristicsTable 2: Index colonoscopy outcomesConclusion: This study demonstrates the increased prevalence of adenomas and advanced adenomas in patients with type 2 diabetes mellitus compared to the general population. Patients with type 2 diabetes mellitus were twice as likely to have adenomas > 1 cm and on average had almost twice the number of polyps on index screening colonoscopy. The evidence demonstrates that diabetes not only increases the risk of the number of adenomatous polyps but impacts the location of advanced adenomas. In this study, diabetics were noted to have a significantly increased risk for proximally located advanced adenomas. Together, this suggests an association between diabetes and colorectal adenomas and adds plausibility that diabetes may play a role in the adenomacarcinoma sequence.