Supporting people with diabetes undergoing endoscopy: Clinical considerations
By Carolien Koreneff, Credentialled Diabetes Educator, Registered Nurse
Hospital admission is common across the general population, but people living with diabetes are at higher risk due to the potential for complications. Approximately 25% of patients admitted to Australian hospitals also have diabetes. Among the most frequently performed procedures that can impact glycaemic control are endoscopies, including gastroscopies, sigmoidoscopies, and colonoscopies.
These procedures often involve fasting, sedation, and altered dietary intake, all factors that can significantly disrupt usual diabetes management. In this article we look at how you can best support your clients before, during, and after an endoscopic procedure.
Understanding endoscopic procedures
Endoscopies are diagnostic and sometimes therapeutic tools that involve inserting a flexible camera (endoscope) into the gastrointestinal tract:
- Gastroscopy: via the mouth into the oesophagus and stomach
- Sigmoidoscopy/Colonoscopy: via the rectum into the colon and small intestine
These procedures typically require sedation or general anaesthesia. While not classified as surgery, the fasting and bowel preparation involved can pose risks for people with diabetes, particularly hypoglycaemia and dehydration.
Indications and risks
Endoscopies are commonly indicated for investigation of gastrointestinal symptoms including abdominal pain, bleeding, ulcers, or suspected malignancy. During colonoscopies, polyps may be removed or biopsies taken.
The overall risk profile is low; however, complications can include:
- Adverse reaction to sedation or anaesthetic
- Bleeding post-polypectomy or biopsy
- Infection
- Aspiration (particularly in those on GLP-1 medications with delayed gastric emptying)
Pre-procedure risk stratification and glycaemic management planning are essential.
Preparation considerations in diabetes
Gastroscopy
- Fasting from approximately 10pm the night prior if scheduled in the morning. For afternoon procedures, a light breakfast may be permitted.
- Minimal dietary disruption, so glycaemic stability is generally maintained.
Colonoscopy
- Soft diet Two days before (low fibre, higher GI foods)
- Clear fluids only the day prior
- Bowel prep (typically consumed the day before)
This preparation can increase the risk of hypoglycaemia and dehydration. Discuss with your client how to manage their medications and advise on appropriate carbohydrate intake using clear fluids with glucose where needed.
Diabetes medication adjustments
Medication adjustments should be individualised and communicated clearly. Key considerations include:
Insulin
- Rapid-acting insulins: Usually withheld during fasting or clear fluid periods
- Premixed insulins: Often reduced or withheld to avoid hypoglycaemia
- Basal insulins: May require dose reduction (e.g. 20–50%) depending on the individual’s usual management, timing, and fasting period
Metformin
- Commonly withheld 24–48 hours pre-procedure due to rare risk of lactic acidosis, particularly with renal impairment or when IV contrast is used.
Sulphonylureas (e.g. gliclazide, glimepiride)
- Generally withheld due to hypoglycaemia risk, particularly in the context of bowel prep and fasting.
SGLT-2 Inhibitors (e.g. empagliflozin, dapagliflozin)
- Should be ceased a day or two pre-procedure due to increased risk of diabetic ketoacidosis (DKA) and dehydration, especially when fasting or during bowel prep.
GLP-1 antagonists and GLP-1/GIP receptor agonists (e.g. Ozempic, Trulicity, Mounjaro)
- Can delay gastric emptying, increasing aspiration risk under sedation.
- May compromise bowel cleansing efficacy.
- May need to be withheld for one or two weeks prior, depending on half-life and clinical urgency of the procedure.
Clinicians must weigh the risks of medication withdrawal (e.g. hyperglycaemia) against procedural safety. Multidisciplinary planning is recommended.
Post-procedural care
- Monitor for delayed return of appetite or gastrointestinal function.
- Advise clients to resume usual diabetes treatment unless otherwise instructed.
- Ensure discharge instructions include clear guidance on medication timing and symptom monitoring.
Clinical tips for supporting clients
- Plan ahead: Provide written instructions and a medication adjustment plan covering two days before, day of, and day after the procedure.
- Flag the diabetes diagnosis with medical teams and recovery staff.
- Avoid double dosing missed medications post-procedure.
- Anticipate glucose variability: Mild hyperglycaemia is common post-procedure; reinforce that this typically resolves within 24–48 hours.
- Encourage people to contact their GP or local hospital if they feel unwell following discharge.
Medication plan template
Encourage clients to record a personalised plan like the following:
| Date | Medications to take (adjusted doses) |
|---|---|
| 2 days before | |
| 1 day before | |
| Procedure day | |
| Day after procedure |
Final notes
Each person requires individualised assessment and planning. Engage early with the medical team to ensure procedural safety and optimal glycaemic outcomes. Ensure clients have a clear understanding of how to self-monitor and when to escalate concerns.