Corticosteroids and Diabetes: How Steroids Cause High Blood Sugar and How to Manage It

When you take corticosteroids like prednisone or dexamethasone for asthma, arthritis, or an autoimmune flare-up, your body doesn’t just fight inflammation-it also starts spiking your blood sugar. For many people, this isn’t just a side effect. It’s a full-blown metabolic crisis that can happen within days of starting treatment. Even if you’ve never had diabetes before, high-dose steroids can push your blood glucose into dangerous territory. And most patients don’t see it coming.

Why Corticosteroids Raise Blood Sugar

Corticosteroids don’t just cause high blood sugar-they actively rewire how your body handles glucose. It’s not a simple case of eating too much sugar. These drugs trigger a cascade of changes in your liver, muscles, fat, and pancreas that work together to flood your bloodstream with glucose.

In your liver, corticosteroids turn on the glucose factory. They ramp up gluconeogenesis-the process of making new glucose from scratch-by 35-40%. That means your liver is pumping out extra sugar even when you haven’t eaten. At the same time, they boost the effect of other stress hormones like glucagon and epinephrine, which also tell your liver to release more glucose.

In your muscles, insulin loses its grip. Normally, insulin opens the door for glucose to enter muscle cells for energy. But corticosteroids block that signal by interfering with GLUT4 transporters. Studies show this cuts glucose uptake by around 30%. Your muscles become insulin resistant, meaning they can’t soak up sugar like they used to.

Your fat tissue isn’t helping either. Corticosteroids increase lipolysis-the breakdown of fat-by 25-30%. This floods your blood with free fatty acids, which further block insulin signaling and make your cells even more resistant. The result? More sugar in your blood, less sugar getting used.

And then there’s your pancreas. Corticosteroids directly reduce insulin production by 20-35%. They lower the expression of GLUT2 and glucokinase, two key proteins your beta cells need to sense glucose and release insulin. At the same time, the extra fatty acids from fat breakdown poison the beta cells, leading to long-term damage. So you’re stuck with rising blood sugar and falling insulin-a double hit.

Who’s Most at Risk?

Not everyone on steroids gets high blood sugar. But some people are far more likely to. The biggest red flags:

• Dose matters: Taking 7.5 mg or more of prednisone daily increases your risk 3.2 times. Every extra 5 mg raises risk by 18%.
• Drug potency: Dexamethasone is 6-8 times more likely to cause hyperglycemia than prednisone at the same anti-inflammatory dose.
• Duration: Risk climbs 12% per week after the first two weeks of treatment.
• Age: Over 50? Your risk jumps 3.1 times.
• Weight: BMI over 25? That’s a 2.5-fold increase.
• History: Previous gestational diabetes? Your risk skyrockets to 4.3 times higher.
• Kidney function: If your eGFR is below 60, your risk is nearly 4 times higher.

People with a family history of type 2 diabetes or those already prediabetic are especially vulnerable. But even healthy, young patients on high-dose steroids can develop steroid-induced diabetes. It’s not about being "unhealthy"-it’s about biology being overwhelmed.

What Does It Feel Like?

Many patients don’t realize their blood sugar is soaring until they’re hospitalized. About 40% of cases show no symptoms at all. But when signs do appear, they’re easy to miss because they look like regular steroid side effects.

• Thirst and frequent urination: 65% and 72% of symptomatic patients report these-classic signs of high glucose pulling water out of your body.
• Extreme fatigue: 81% of patients feel unusually tired, even after rest.
• Blurred vision: High sugar swells the lens of your eye, making focus hard. Happens in 32% of cases.
• Increased hunger: 85% of steroid users report this-but it’s not hunger for food. It’s your body screaming for energy because cells can’t use glucose.
• Mood swings: 67% report irritability or anxiety. This isn’t just stress-it’s your brain reacting to unstable glucose levels.

And here’s the cruel twist: weight gain from steroids (2.5-4 kg in the first month) gets mistaken for just another side effect. But it’s often visceral fat building up because of insulin resistance. Your body is storing fat instead of burning fuel.

How Doctors Monitor and Diagnose It

There’s no single test for steroid-induced diabetes. Diagnosis relies on timing, dose, and glucose readings. The NIH recommends checking blood sugar at least twice daily for anyone on prednisone 20 mg or higher. For dexamethasone or other potent steroids, monitoring should start immediately.

Doctors look for:

• Fasting glucose over 140 mg/dL (7.8 mmol/L)
• Random glucose over 180 mg/dL (10.0 mmol/L)
• HbA1c rising rapidly during treatment (even if it was normal before)

But here’s the problem: most primary care providers don’t screen unless symptoms appear. A 2022 audit found that 35% of patients on long-term steroids never got their blood sugar checked. That’s dangerous. Hyperglycemia can escalate fast-leading to hyperosmolar hyperglycemic state (HHS) in 4-8% of severe cases, with a 15-20% mortality rate.

Patients who report delayed diagnosis often wait 9.3 days from first symptoms to confirmation. By then, they’re already in crisis.

How to Manage Steroid-Induced Hyperglycemia

Management isn’t about diet and exercise alone. You need targeted medical intervention.

Insulin is the gold standard. Unlike oral meds, insulin works regardless of insulin resistance. The UCSF protocol recommends:

• Basal insulin: Increase by 20% for every 10 mg above 20 mg of prednisone daily.
• Mealtime insulin: Use a 1 unit per 5-10g carb ratio.

For example, someone on 40 mg prednisone would need about 40% more basal insulin than their usual dose. Timing matters too-steroids peak 4-8 hours after ingestion, so glucose should be checked 6 hours after the morning dose.

Oral meds? Proceed with caution. Sulfonylureas like glipizide can help by forcing the pancreas to release more insulin. But they’re risky. When steroids are tapered, insulin production doesn’t bounce back immediately. That creates a dangerous mismatch-medication still active, but less sugar to clear. This leads to hypoglycemia in 37% of cases if not adjusted.

GLP-1 receptor agonists (like semaglutide) are being studied in the NIH’s GLUCO-STER trial. Early results show 28% lower hypoglycemia risk compared to insulin. But they’re not yet standard for short-term use.

For patients with pre-existing type 2 diabetes, insulin needs often jump 50-100% during steroid treatment. Many don’t realize this until they’re in the ER.

What Happens When You Stop Steroids?

Good news: steroid-induced diabetes is usually temporary. Blood sugar typically normalizes within 3-5 days after stopping the drug. But here’s where things go wrong:

• Many patients keep taking diabetes meds out of habit.
• Doctors don’t always tell them to stop.
• Some patients are told they "have diabetes now"-even if it was only steroid-triggered.

One Reddit user, who took prednisone for a lupus flare, said her doctor prescribed metformin and never followed up. Three months later, she was still on it. Her blood sugar was normal. She had no symptoms. But she was taking a drug she didn’t need.

That’s why education matters. Patients need clear instructions: "When you finish your steroids, check your blood sugar daily for a week. If it’s under 100 mg/dL fasting and under 140 mg/dL after meals, you likely don’t need meds anymore. Call your doctor to confirm."

The Bigger Picture

Corticosteroids are essential. Millions rely on them. But their metabolic cost is underrecognized. About 1-2% of the population takes systemic steroids each year. For those over 65, it’s 8-10%. That’s millions of people at risk.

Hospitalized patients on high-dose steroids have a 45-60% chance of needing glucose control. That adds 2.3 extra days in the hospital and $2,800-$4,200 in costs per admission. Primary care is failing to catch cases early. The FDA has required hyperglycemia warnings on labels since 2018, but that doesn’t change practice.

Emerging therapies are making this worse. CAR-T cancer treatments now commonly include steroids, and 75-85% of those patients develop hyperglycemia. New autoimmune treatments are increasing steroid use. The Endocrine Society predicts steroid-induced diabetes will be the third most common cause of secondary diabetes by 2030.

But there’s hope. The European Association for the Study of Diabetes launched the STEROID-Glucose app in 2023. It gives real-time insulin dose suggestions based on steroid type and glucose readings. Pilot studies showed a 32% drop in high-blood-sugar events.

And researchers are developing new steroids-tissue-selective glucocorticoid receptor modulators-that fight inflammation without wrecking glucose control. Compound XG-201, in phase II trials, reduced hyperglycemia by 65% compared to prednisone at the same dose.

Until those drugs are available, the best defense is awareness. If you’re on steroids, ask: "Will this affect my blood sugar? Should I be checking it? What should I do if it goes high?" Don’t wait for symptoms. Don’t assume it’s just fatigue or hunger. Ask for a glucose monitor. It could save your life.