Steroid-Induced Diabetes

How steroids raise blood sugar

Glucocorticoids:

• make the liver produce more glucose
• reduce how well muscle and fat respond to insulin (insulin resistance)
• reduce insulin release from the pancreas
• increase appetite and promote weight gain

With a single morning dose of prednisone or prednisolone, blood sugar typically starts rising 4 to 8 hours later, peaks in the afternoon and evening, and returns toward normal overnight. Longer-acting steroids such as dexamethasone can raise blood sugar throughout the day.

Who is at risk

• People with existing type 2 diabetes or prediabetes
• Family history of diabetes
• Overweight or obesity
• Older age
• History of gestational diabetes
• High steroid doses or long courses
• Certain ethnic backgrounds with higher diabetes rates
• Hospital patients receiving high-dose IV steroids

Inhaled, nasal, skin and joint injection steroids rarely cause significant problems, although joint injections can raise blood sugar for a few days in people with diabetes.

Symptoms

Many people have no symptoms. When blood sugar is high, symptoms include:

• Excessive thirst
• Frequent urination, including at night
• Tiredness
• Blurred vision
• Increased hunger
• Slow-healing infections such as thrush or skin infections

Very high levels can lead to hyperosmolar hyperglycemic state, a serious emergency.

Diagnosis and monitoring

Because blood sugar rises later in the day, a morning fasting test can miss steroid-induced diabetes. Recommended approaches:

• Check blood sugar before lunch or the evening meal, or 1 to 2 hours after lunch, when steroids have their greatest effect
• In hospital, regular finger-stick checks for people on high-dose steroids
• A random blood sugar of 200 mg/dL (11.1 mmol/L) or more with symptoms suggests diabetes
• HbA1c is useful for checking pre-existing diabetes but is less reliable for short steroid courses, since it reflects the previous 2 to 3 months

Treatment

For people without previous diabetes

• Mild elevations may need only monitoring and diet changes
• If blood sugar is consistently high (often above about 200 to 250 mg/dL in the afternoon), medicines are started

Medicines

• NPH (intermediate-acting) insulin given in the morning alongside the steroid dose is commonly used, because its action matches the steroid's effect
• Mealtime insulin for larger post-meal rises
• Oral medicines such as metformin, sulfonylureas (taken in the morning) or DPP-4 inhibitors may be used in milder cases
• Basal insulin adjustments for people already on insulin, plus extra doses as needed

When steroids are reduced or stopped

Diabetes medicine doses must be reduced in step with steroid tapering to prevent low blood sugar. Your healthcare team will give you a plan.

Lifestyle

• Limit sugary drinks and refined carbohydrates, especially at lunch and dinner
• Stay active as health allows
• Monitor weight

Outlook

For most people without previous diabetes, blood sugar returns to normal within days to weeks after stopping steroids. Some, especially those with prediabetes or other risk factors, develop persistent type 2 diabetes. People who have had steroid-induced diabetes should have periodic diabetes screening afterward.

Long-term steroid use has other effects, including weight gain, bone loss and muscle weakness. See steroid-induced complications and Cushing syndrome.

Frequently asked questions

Can steroids cause diabetes?

Yes. Glucocorticoid steroids such as prednisone and dexamethasone raise blood sugar by increasing glucose production and causing insulin resistance. This can cause diabetes in people who did not have it before, especially with high doses or existing risk factors.

How long does steroid-induced diabetes last?

It often resolves within days to weeks after steroids are stopped. In people with prediabetes, obesity or a family history of diabetes, it may reveal underlying type 2 diabetes that persists.

When should blood sugar be checked on steroids?

With a morning steroid dose, check blood sugar before lunch or before the evening meal, when levels are highest. A fasting morning check alone can miss steroid-related high blood sugar.

How is steroid-induced diabetes treated?

Treatment depends on severity. Options include diet changes, oral medicines such as metformin or a morning sulfonylurea, and often NPH insulin given in the morning to match the steroid's effect. Doses are reduced as steroids are tapered.

Do steroid inhalers raise blood sugar?

Usually not significantly. Inhaled, nasal and topical steroids have little effect on blood sugar at standard doses. Steroid injections into joints can cause a temporary rise for a few days in people with diabetes.