Diabetic patients before surgery — HbA1c, HOMA-IR, and glucose management
Diabetes changes wound healing, infection risk, anaesthesia interactions, and recovery time. Before any operation on a diabetic patient, Dr. Khaled Ghalwash and Dr. Mohamed Ghalwash add an extended workup to the standard panel, with thresholds that follow 2025 ADA and 2024 ASA guidance.
The most cited number on this page is the elective-surgery target. The most asked question on this page is when HOMA-IR is ordered, and what it actually tells the surgeon. Both are answered explicitly below.
The diabetic add-on panel
Beyond the standard panel that every patient receives, Dr. Khaled Ghalwash adds the following to every diabetic patient before any operation. Each test answers a specific question about safety or healing.
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1
HbA1c plus fasting glucose
HbA1c gives a 3-month average. Fasting glucose gives the now. Both are needed because a recent infection or steroid course can shift the now without yet shifting the average.
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2
Fasting insulin and HOMA-IR (when indicated)
For pre-bariatric patients and for any patient with BMI > 35 plus uncertain diabetes status. HOMA-IR is calculated, not measured, so the cost is the cost of fasting insulin.
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3
Microalbuminuria and renal function
Diabetes is the leading cause of kidney disease. The standard panel covers creatinine; we add urine microalbumin to detect early diabetic nephropathy that changes contrast and antibiotic dosing.
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4
Lipid panel and fundoscopy referral
Total cholesterol, LDL, HDL, triglycerides. Plus a referral to ophthalmology for retinal screening if not done in the past 12 months.
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5
Medication and injection plan
GLP-1 agonists (Ozempic, Mounjaro), SGLT2 inhibitors (Forxiga, Jardiance), Metformin, sulphonylureas, and insulin each have their own stop-and-restart timing. The plan is built once and given to the patient on paper.
When we order HOMA-IR (and what it does not predict)
HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is a calculation from fasting glucose and fasting insulin: HOMA-IR = (fasting insulin × fasting glucose) ÷ 405. The number describes how hard the pancreas is working to keep blood sugar normal. Higher numbers mean more insulin resistance.
Dr. Khaled Ghalwash treats HOMA-IR like a metabolic snapshot, not a crystal ball. Before bariatric surgery, the number tells us where you are. After surgery, it tells us how far you've moved. The before-and-after pair is the value, not the single reading.
HbA1c targets and the optimisation window
| HbA1c | Elective surgery | Urgent (within weeks) | Emergency |
|---|---|---|---|
| < 7% | Proceed | Proceed | Proceed |
| 7.0 — 7.9% | Proceed | Proceed | Proceed |
| 8.0 — 8.9% | Optimise 2-4 weeks | Proceed with tight glucose plan | Proceed |
| > 9% | Optimise 4-8 weeks | Endocrinology co-management | Proceed with insulin protocol |
GLP-1, SGLT2, and Metformin handling
The 2024 ASA guidance on GLP-1 agonists and the 2024 FDA warning on SGLT2 euglycaemic ketoacidosis changed pre-operative practice. Skipping these stops is no longer optional.
| Medication | Stop before surgery | Restart | Why |
|---|---|---|---|
| GLP-1 weekly (Ozempic, Mounjaro, Wegovy) | 7 days | Day 3-5 post-op once eating resumes | Slowed gastric emptying = aspiration risk under anaesthesia (2024 ASA) |
| GLP-1 daily (Victoza, Saxenda) | 24 hours | Day 2-3 post-op | Same mechanism, shorter half-life |
| SGLT2 (Forxiga, Jardiance, Invokana) | 3 days | Once eating, hydrated, glucose stable | Euglycaemic DKA risk (2024 FDA warning) |
| Metformin | Morning of surgery; 48 hours after if IV contrast given | Day 2 post-op once eating | Lactic acidosis risk in dehydration or contrast-affected kidneys |
| Sulphonylureas (gliclazide, glimepiride) | Morning of surgery | Once eating | Hypoglycaemia risk during fast |
| Long-acting insulin (Lantus, Toujeo, Tresiba) | Reduce by 20-30% night before | Same dose unless glucose pattern changed | Fasting reduces basal needs slightly |
| Short-acting insulin | Hold morning of surgery | Sliding scale until eating resumes | No food = no bolus need |
Day-of glucose management
The day-of-surgery target for elective procedures is 140 to 180 mg/dL (7.8 to 10 mmol/L). Below 140 is fine and we do not give correction. Above 250 to 300, we usually postpone unless emergent. The team monitors every 1 to 2 hours intra-operatively and corrects with insulin as needed. We do not cancel for borderline numbers; we manage them.
After surgery: continuing the plan
The post-operative diabetes management plan is built before surgery, not after. Stress hormones from surgery typically raise blood sugar for 3 to 7 days, even in well-controlled diabetes. We anticipate this, increase insulin temporarily, then taper back. Patients leave with a written sliding scale and follow-up arranged.
Bariatric surgery patients have their own track: medications often reduce within days because of caloric restriction, and full medication review happens at the 2-week and 6-week visits. The science of recovery covers what your body does in the first weeks.
Frequently asked questions
What is HOMA-IR and what does it tell us before surgery?
HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is a simple calculation from fasting glucose and fasting insulin. It measures how much insulin your body needs to keep blood sugar normal. Before bariatric surgery, Dr. Khaled Ghalwash uses it as a metabolic snapshot, not as a tool to predict whether your diabetes will go into remission. 2025 evidence is clear: HOMA-IR describes your current state, it does not predict the future.
I have type 2 diabetes and want a gastric sleeve, what tests do I need?
Standard panel plus extended diabetic workup: HbA1c, fasting glucose and insulin, HOMA-IR, lipid panel, microalbuminuria, fundoscopy referral, and renal function. We aim for HbA1c under 8% before elective bariatric surgery. If you are above that, we optimize for 4 to 8 weeks before scheduling.
My HbA1c is 7.8%, can I have surgery?
Yes. The 2025 ADA target for elective surgery is under 8%, which you meet. Different societies set different targets between 7.0% and 9.0% but 8% is the most defensible threshold for elective procedures. For emergency surgery, we operate at any HbA1c.
Should I stop metformin before surgery?
Hold metformin on the morning of surgery and for 48 hours after if IV contrast is given or kidney function may be stressed. For uncomplicated bariatric or laparoscopic surgery without contrast, restart on day 2 once eating resumes. Talk to the team about your specific procedure.
I take Ozempic, do I need to stop it before surgery?
Yes. The 2024 ASA guidance recommends holding GLP-1 agonists like Ozempic for 1 week before any surgery requiring anesthesia. They slow gastric emptying and increase aspiration risk. For weekly injections, the last dose is 7 days before. For daily injections, 24 hours.
If my blood sugar spikes the day of surgery, will it be cancelled?
Sometimes. The day-of target is 140 to 180 mg/dL for elective surgery. Above 250 to 300 we usually postpone unless emergent. Below 140 is fine. The team monitors and corrects with insulin during and after surgery. We do not cancel for borderline numbers, we manage them.
Schedule with Dr. Khaled Ghalwash and Dr. Mohamed Ghalwash
Diabetic patients planning surgery: book a pre-operative consultation. We coordinate with your endocrinologist, build your medication plan, and confirm timing only when your numbers are where they need to be.
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