What diabetics need to know about surgery

Patients with diabetes know that the disease complicates everyday life, from testing your blood sugar to dietary changes. Most are aware that it can also have long-term consequences on your health, especially your heart, kidneys and blood vessels. Not all realise that it can complicate routine surgery, from medication changes to your recovery. Here are four things you need to know about surgery if you have diabetes.

Medication changes

Some blood sugar medications need to be stopped before surgery or taken at different times. There are several reasons for this.  Surgery and some anaesthetic medications change your metabolism in ways that can alter how your body uses sugar. In addition, you'll be fasting so should not require some medications at the same dose or at all. Some medications such as insulin and sulfonylureas carry a risk of low blood sugar are stopped to prevent your blood sugar dropping to dangerous levels during the surgery.  The Australian Diabetes Society recommends that oral medications to control blood sugar such as metformin and sulfonylureas like gliclazide should generally not taken on the day of surgery.  Insulin will usually require very careful management about when to stop and what needs to be done from there.  Often you'll need to be admitted prior to your surgery so that your blood sugar can be carefully monitored while fasting.  This may be done as you receive insulin and sugary fluid through a drip to optimise your blood sugars before the surgery.

People with diabetes are more likely to be on other medications for conditions such as high blood pressure, high cholesterol and blood thinners. These medications also sometimes need to be stopped before surgery. Your doctor will let you know exactly which medications need to be stopped before surgery and when they need to be stopped.


Fasting before surgery is important to reduce the chance of complications from anaesthetics and sometimes from the surgical procedure itself.  While you will still be told to fast the regular guidelines are sometimes altered for a patient with diabetes given the impact it will have on your blood sugar.  Your surgery may be the first on the list to reduce the risk of delays which would mean you'd be fasting for longer than necessary.

Infection risk

Diabetes and the high blood sugar levels that come from it are both associated with an increased risk of infection after surgery.  Your doctors and nurses will keep a close eye on your recovery to make sure you have no signs of infection.  You'll need to make sure you take any antibiotics as they are prescribed.  Eating well, testing blood sugars at regular intervals and taking your diabetes medication as prescribed will reduce your risk of getting an infection after your surgery.  Make sure that you know the signs of infection and when to seek further medical review before you're discharged.

Healing times

Unfortunately, high blood sugar impairs wound healing.  This means that your body takes longer to repair tissues that have been damaged.  Given this, people with diabetes may take longer to heal after surgery.  For this reason, it's important to keep a close eye on your blood sugars throughout your recovery period.  Aim to keep them within the target range as best you can.  Discuss the recovery period with your doctor before the surgery and how you can monitor your wounds to make sure they're healing as they should.

Make sure you have very clear instructions about all of these things from your doctor before your surgery.  While these are general guidelines it's important to not stop any medication or fast without clear advice from your doctor.  Your individual situation may mean you need different care. If you understand exactly what needs to be done you can reduce the risk of complications during your surgery and recovery.