Recommendations Issued for Diabetes-Specific Colonoscopy Preparation

Diabetes-specific protocols for colonoscopy preparation should be used to decrease risk for adverse events.

Individuals with diabetes preparing for colonoscopy should receive a personalized, pre-procedural dietary plan with appropriate adjustment of antihyperglycemic agents (AHAs), according to study results published in Journal of the Canadian Association of Gastroenterology.

Researchers from the University of Toronto and Sunnybrook Health Science Center in Canada searched publication databases from March 2001 to June 2022 for guidelines on colonoscopy preparations in individuals with diabetes. A total of 67 articles were included in their review.

Among the general population, the typical guidance is to maintain a clear fluid diet the day before colonoscopy. In patients with diabetes, this hypocaloric diet can cause electrolyte imbalance and/or diabetic ketoacidosis, both of which can lead to acute kidney injury. To avoid adverse outcomes, patients with diabetes should be advised to avoid clear fluids high in glucose, consume 45 g carbohydrates for meals and 15g to 30 g for snacks, and consume fluids that contain electrolytes. In addition, some evidence suggests that patients with diabetes who consume a normal breakfast the day before colonoscopy have improved bowel preparation and tolerability of the clear fluid diet.

For large bowel lavage, a polyethylene glycol (PEG) preparation is standard. In the setting of diabetes, a split-dose approach has been associated with reduced rates of inadequate bowel preparation. In addition, adding lubipristone to PEG, delaying clear fluid diet, providing patients with a low-residue dietary plan, and modifying AHA use have been associated with improved bowel preparation.

PWD should be given a personalized diet plan by their healthcare provider for the days leading up to their colonoscopy.

As colonoscopy preparation disrupts glucose intake patterns, glucose should be monitored before all meals and at bedtime. The day before colonoscopy, blood monitoring should occur every 4 hours from 7:00am or when symptoms occur. If glucose drops below 5 mmol/L, patients should be advised to consume high-glucose fluids and if glucose increases above 10 mmol/L, no glucose-containing fluids should be consumed. At sedation, a point-of-care glucose assessment should be performed.

The review authors recommended for sodium-glucose cotransporter 2 (SGLT-2) inhibitors to be stopped 3 days before colonoscopy, glucagon-like peptide 1 (GLP-1) antagonists to be stopped 2 days before colonoscopy, sulfonylureas to be stopped, intermediate acting AHAs and first-generation basal AHAs to be taken at an 80% dose, and second-generation basal AHAs to be taken at a 50% to 80% dose depending on type of diabetes the day before colonoscopy. Biguanides and meglitinides should be stopped and insulins should be reduced by half at clear diet initiation. Lastly, dipeptidyl peptidase IV (DPP-4) inhibitors should be stopped the day of colonoscopy.

The authors conclude, “PWD should be given a personalized diet plan by their healthcare provider for the days leading up to their colonoscopy. Additionally, diabetes-specific protocols for large bowel lavage should be used to decrease the likelihood of inadequate bowel preparation and its associated risks. AHAs must be appropriately adjusted due to the risk of AHA-related complications in the context of colonoscopy preparation. Lastly, PWD should be counselled on monitoring for symptoms of hypo- and hyperglycemia and should frequently check their blood glucose in the peri-colonoscopy period.”

Disclosure: An author declared affiliations with industry. Please refer to the original article for a full list of disclosures.

This article originally appeared on Gastroenterology Advisor


Chirila A, Nguyen ME, Tinmouth J, Halperin IJ. Preparing for colonoscopy in people with diabetes: a review with suggestions for clinical practice. J Can Assoc Gastroenterol. 2022:gwac035. doi:10.1093/jcag/gwac035