Researchers studied what happens to blood sugar levels when people with diabetes receive a steroid injection to help with pain. They found that blood sugar levels jumped significantly after the injection, reaching dangerous highs in many patients. The study of 50 diabetic patients showed that people whose diabetes was harder to control (measured by a test called HbA1c) experienced the biggest blood sugar spikes. This matters because doctors need to know which diabetic patients are at highest risk when receiving these common pain-relief injections, so they can monitor them more carefully.

The Quick Take

  • What they studied: How a steroid medication called dexamethasone affects blood sugar levels in people who have diabetes
  • Who participated: 50 people with diabetes who were having nerve pain procedures at a hospital in Japan. All received the same dose of steroid injection.
  • Key finding: Blood sugar levels more than doubled after the injection, peaking at an average of 328 mg/dL (normal is under 100). People whose diabetes was already harder to control had the biggest increases.
  • What it means for you: If you have diabetes and need a steroid injection for pain, your doctor should monitor your blood sugar closely afterward. People with poorly controlled diabetes should be especially careful and may need extra monitoring or medication adjustments.

The Research Details

This was a cohort study, which means researchers followed a group of 50 people with diabetes over time to see what happened after they received a steroid injection. All patients received the same dose of dexamethasone (a common steroid) as part of a nerve pain treatment procedure. The researchers used a special continuous glucose monitor (like a small sensor worn on the skin) to track blood sugar levels minute-by-minute before, during, and after the injection. They then looked at which patient characteristics predicted who would experience the biggest blood sugar spikes.

The researchers measured four things about each patient: their HbA1c level (a test showing average blood sugar control over 3 months), age, body weight, and their blood sugar level right before the procedure. They used statistical analysis to figure out which of these factors best predicted who would have dangerous blood sugar levels after the injection.

Understanding which diabetic patients are at highest risk for dangerous blood sugar spikes after steroid injections helps doctors make better decisions about monitoring and treatment. This is important because steroids are commonly used for pain relief, and diabetic patients need special care when receiving them.

This study has some strengths: it used continuous glucose monitoring (very accurate), had a clear definition of dangerous blood sugar levels, and used proper statistical methods. However, there are limitations: the sample size was relatively small (50 people), it was done at only one hospital in Japan, and researchers didn’t track all the details that might affect results (like what patients ate, exact insulin doses, or other medications that might interact with the steroid).

What the Results Show

Blood sugar levels increased rapidly after the steroid injection in all diabetic patients. The average peak blood sugar was 328 mg/dL, which is dangerously high (normal fasting blood sugar is under 100 mg/dL). It took about 10 hours for blood sugar to reach its highest point after the injection.

The most important finding was that two factors predicted who would have the biggest blood sugar problems: age and HbA1c level. Patients with higher HbA1c levels (meaning their diabetes was already harder to control) experienced significantly larger blood sugar spikes. Older patients also tended to have bigger increases.

Patients taking insulin for their diabetes had much higher blood sugar levels after the injection compared to those taking other diabetes medications or no medications at all. This suggests that insulin-dependent diabetes may be more sensitive to steroid effects.

The study found that body weight and blood sugar level before the procedure were not strong predictors of how much blood sugar would spike. This was somewhat surprising and suggests that the steroid’s effect on blood sugar is more related to how well someone’s diabetes is controlled overall rather than their current weight or pre-procedure blood sugar.

This study builds on earlier research showing that steroids increase blood sugar in people without diabetes. The new finding is that people with diabetes have much more dramatic increases, and that those with poorly controlled diabetes (higher HbA1c) are at highest risk. This helps explain why diabetic patients need special monitoring when receiving steroids.

Several factors could have affected the results but weren’t fully measured: the study didn’t track what patients ate before or after the procedure, didn’t record exact insulin doses and timing, didn’t account for stress from the procedure itself (which can raise blood sugar), and didn’t fully document other medications patients were taking that might interact with the steroid. The study was also done at only one hospital with a relatively small group of patients, so results may not apply to all diabetic patients everywhere.

The Bottom Line

If you have diabetes and need a steroid injection for pain relief: (1) Tell your doctor about your diabetes and ask about blood sugar monitoring after the procedure (moderate confidence); (2) Check your blood sugar more frequently for 24 hours after the injection (moderate confidence); (3) If your diabetes is hard to control (high HbA1c), ask your doctor if you need extra monitoring or temporary medication adjustments (moderate confidence). These recommendations are based on this single study and should be discussed with your healthcare provider.

This research is most important for: people with diabetes who need steroid injections for pain, their doctors, and people with poorly controlled diabetes (HbA1c above 7%). People without diabetes don’t need to worry about these findings. People whose diabetes is well-controlled should still be cautious but may have smaller blood sugar increases.

Blood sugar spikes occurred quickly—within hours of the injection—and peaked around 10 hours after the injection. Most patients likely returned to normal blood sugar levels within 24 hours, but this wasn’t fully documented in the study. People taking insulin may take longer to normalize.

Want to Apply This Research?

  • If you receive a steroid injection, track your blood sugar every 2-3 hours for the first 24 hours after the procedure. Record the time, blood sugar reading, and any symptoms (thirst, fatigue, headache). Compare these readings to your normal daily patterns.
  • Set phone reminders to check blood sugar at regular intervals after a steroid injection. If using a continuous glucose monitor, review the data with your doctor within 24-48 hours. Discuss with your doctor whether you need temporary adjustments to your diabetes medications on the day of the procedure.
  • Keep a log of steroid injections and corresponding blood sugar responses. Over time, this helps you and your doctor predict your personal reaction and plan better for future procedures. Share this information with all your healthcare providers.

This research describes what happened in one study of 50 people and should not replace medical advice from your doctor. If you have diabetes and need a steroid injection, discuss these findings with your healthcare provider before the procedure. Do not change your diabetes medications without talking to your doctor first. This information is educational and not a substitute for professional medical diagnosis, treatment, or care. Individual responses to steroid injections vary, and your doctor knows your specific health situation best.