Steroid-Induced Hyperglycemia

Glucocorticoids can unmask diabetes that was previously compensated for, worsen established diabetes, or cause new hyperglycemia in a person with no prior diabetes history. This is common: Diabetes Canada reports a prevalence between 20% and 50% among people without a previous history of diabetes. The central problem is insulin resistance. In skeletal muscle, glucose transport into cells falls because insulin signalling no longer moves glucose transporters effectively to the cell surface. In the liver, insulin becomes less able to suppress glucose production, so hepatic gluconeogenesis rises. Visceral adiposity and, over time, beta-cell stress further weaken the body's ability to meet the higher insulin demand. This physiology produces a pattern that a morning fasting test can miss. When prednisolone is given as a single morning dose, it causes a distinctive daily pattern of hyperglycemia, with peak glucose approximately 8 hours after the dose and elevations mostly in the afternoon and evening. A patient taking prednisone at 0800 may have an acceptable glucose before breakfast, then develop marked hyperglycemia after lunch and dinner. Relying on a morning fasting glucose alone may underestimate...