Exploring the associations between colorectal polyps and type 2 diabetes mellitus in a colonoscopy clinic population

Introduction

An association has consistently been reported between type 2 diabetes mellitus (T2DM) and colorectal cancer (CRC). CRC develops within premalignant polyps. The aim of this work was to examine the relationship between colorectal polyp subtypes and T2DM across the population, including in low- and non-screening age groups.

Material and methods

A cross-sectional study was carried out using an audit of a colonoscopy database and histopathology reports at a tertiary teaching hospital during 2016. Included were consecutive patients undergoing colonoscopy for a diverse range of indications. Univariable and multivariable analyses were carried out to assess the associations between T2DM, age, sex, indications for the procedure and different types of colorectal polyps.

Results

Data were extracted from colonoscopies in 1395 patients. Evidence of T2DM was observed in 257 (18%) patients. Any adenoma was present in 109 (42%) patients with T2DM compared with 256 (22%) patients with no evidence of T2DM [odds ratio (OR) 2.5, 95% confidence interval (CI) 1.9-3.4, P < 0.001]. In patients <50 years of age, occult bleeding was associated with any adenoma (OR 3.1, 95% CI 1.2-7.8, P = 0.03) and advanced adenoma (OR 21, 95% CI 1.8-240, P = 0.02). A multinomial logistic regression determined that male sex, T2DM, blood in the stool and older age were all independently associated with the presence of any adenoma.

Conclusions

Adenomas were independently associated with T2DM. Given the consistent association between CRC and T2DM, these data suggest that a diagnosis of T2DM may warrant closer colorectal surveillance.