Intest Res.  2014 Apr;12(2):139-145. 10.5217/ir.2014.12.2.139.

Does Metformin Affect The Incidence of Colonic Polyps and Adenomas in Patients with Type 2 Diabetes Mellitus?

• Cho YH
• Ko BM
• Kim SH
• Myung YS
• Choi JH
• Han JP
• Hong SJ
• Jeon SR
• Kim HG
• Kim JO
• Lee MS

• KMID: 2284899
• DOI: http://doi.org/10.5217/ir.2014.12.2.139

Abstract

BACKGROUND/AIMS
Colorectal cancer (CRC) develops from colonic adenomas. Type 2 diabetes mellitus (DM) is associated with a higher risk of CRC and metformin decreases CRC risk. However, it is not certain if metformin affects the development of colorectal polyps and adenomas. This study aimed to elucidate if metforminaffects the incidence of colonic polyps and adenomas in patients with type 2 DM.
METHODS
Of 12,186 patients with type 2 DM, 3,775 underwent colonoscopy between May 2001 and March 2013. This study enrolled 3,105 of these patients, and divided them in two groups: 912 patients with metformin use and 2,193 patients without metformin use. Patient clinical characteristics, polyp and adenoma detection rate in the two groups were analyzed retrospectively.
RESULTS
The Colorectal polyp detection rate was lower in the metformin group than in the non-meformin group (39.4% vs. 62.4%, P<0.01). Colorectal adenoma detection rate was significantly lower in the metformin group than in the non-metformin group (15.2% vs. 20.5%, P<0.01). Fewer advanced adenomas were detected in the metformin group than in the non-metformin group (12.2% vs. 22%, P<0.01). Multivariate analysis identified age, sex, Body mass index and metformin use as factors associated with polyp incidence, whereas only metforminwas independently associated with decreased adenoma incidence (Odd ratio=0.738, 95% CI=0.554-0.983, P=0.03).
CONCLUSIONS
In patients with type 2 DM, metformin reduced the incidence of adenomas that may transform into CRC. Therefore, metformin may be useful for the prevention of CRC in patients with type 2 DM.

Keyword

Colon adenoma; Adenoma detection rate; Polyp detection rate; Metformin; Diabetes mellitus, type 2

MeSH Terms

Adenoma*
Body Mass Index
Colon
Colonic Polyps*
Colonoscopy
Colorectal Neoplasms
Diabetes Mellitus, Type 2*
Humans
Incidence*
Metformin*
Multivariate Analysis
Polyps
Retrospective Studies
Metformin

Figure

• 

  Fig. 1 Overview of the selection process. DM, diabetes mellitus.

• 

  Fig. 2 Comparison of polyp detection rate (PDR) and adenoma detection rate (ADR) based on duration of metformin use.

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