Glycemic Control, Colorectal Adenoma, and Cancer Risk in Patients With Type 2 Diabetes

Optimal glycemic control in patients with Type 2 diabetes mellitus (T2DM) was linked to a reduced risk of colorectal adenoma and colorectal cancer (CRC), with a clear dose-response relationship observed between glycemic control and CRC risk, Ka Shing Cheung, MBBS, MPH, said at Digestive Disease Week on May 19.

Dr Cheung, from the University of Hong Kong, reported on the “Association Between Glycemic Control and Colorectal Adenoma and Cancer Risk in Patients with Type 2 Diabetes Mellitus: A Population-Based Cohort Study.” He and colleagues aimed to investigate the relationship between glycemic control and the risk of colonic adenoma and CRC) development in patients with newly diagnosed T2DM. Conducted as a retrospective cohort study in Hong Kong using electronic healthcare data from 2005 to 2013, the research assessing their baseline glycemic levels and subsequent outcomes.

The primary exposure was defined as optimal glycemic control at baseline, characterized by a mean hemoglobin A1c (HbA1c) level below 7%. Propensity score matching was employed to derive subdistribution hazard ratios (SHR) for CRC and colonic adenoma, considering various covariates including age, sex, diabetic complications, body mass index, and comorbidities.

Results from 88,468 propensity score-matched T2DM patients revealed a beneficial effect of optimal glycemic control on CRC risk, with a SHR of 0.72 (95% CI: 0.65-0.81). This effect was particularly pronounced for tumors in the rectum and left-sided colon. Additionally, optimal glycemic control was associated with a decreased risk of any adenoma, nonadvanced adenoma, and advanced colonic adenoma.

Furthermore, a stepwise increase in CRC risk was observed with higher HbA1c levels, indicating a biological gradient. Suboptimal glycemic control at baseline/postbaseline was associated with a higher risk of CRC compared to optimal control during both time periods.

These findings emphasize the importance of glycemic management in mitigating colorectal neoplasia risk among diabetic individuals, Dr Cheung said.

Reference
Cheung KS, Xianhua M, Tan JT, Cheng HM, et al. Association between glycemic control and colorectal adenoma and cancer risk in patients with type 2 diabetes mellitus: a population-based cohort study. Poster presented at: Digestive Disease Week; May 18-21, 2024; Washington, DC.