Impact of type 2 diabetes on adenoma detection in screening colonoscopies performed in disparate populations

Abstract

Background: The Black/African Ancestry (AA) population has a higher prevalence of type 2 diabetes mellitus (T2DM) and a higher incidence and mortality rate for colorectal cancer (CRC) than all other races in the United States. T2DM has been shown to increase adenoma risk in predominantly white/European ancestry (EA) populations, but the effect of T2DM on adenoma risk in Black/AA individuals is less clear. We hypothesize that T2DM has a significant effect on adenoma risk in a predominantly Black/AA population.

Aim: To investigate the effect of T2DM and race on the adenoma detection rate (ADR) in screening colonoscopies in two disparate populations.

Methods: A retrospective cohort study was conducted on ADR during index screening colonoscopies (age 45-75) performed at an urban public hospital serving a predominantly Black/AA population (92%) (2017-2018, n = 1606). Clinical metadata collected included basic demographics, insurance, body mass index (BMI), family history of CRC, smoking, diabetes diagnosis, and aspirin use. This dataset was combined with a recently reported parallel retrospective cohort data set collected at a suburban university hospital serving a predominantly White/EA population (87%) (2012-2015, n = 2882).

Results: The ADR was higher in T2DM patients than in patients without T2DM or prediabetes (35.2% vs 27.9%, P = 0.0166, n = 981) at the urban public hospital. Multivariable analysis of the combined datasets showed that T2DM [odds ratio (OR) = 1.29, 95% confidence interval (CI): 1.08-1.55, P = 0.0049], smoking (current vs never OR = 1.47, 95%CI: 1.18-1.82, current vs past OR = 1.32, 95%CI: 1.02-1.70, P = 0.0026), older age (OR = 1.05 per year, 95%CI: 1.04-1.06, P < 0.0001), higher BMI (OR = 1.02 per unit, 95%CI: 1.01-1.03, P = 0.0003), and male sex (OR = 1.87, 95%CI: 1.62-2.15, P < 0.0001) were associated with increased ADR in the combined datasets, but race, aspirin use and insurance were not.

Conclusion: T2DM, but not race, is significantly associated with increased ADR on index screening colonoscopy while controlling for other factors.

Keywords: Adenoma; African continental ancestry group; Colonoscopy; Diabetes mellitus, type 2; European continental ancestry group; Multivariate analysis.