Does insulin requirement increase or decrease during illness?

Insulin Requirements Increase During Illness

Insulin requirements increase during acute illness due to elevated counterregulatory hormones that induce insulin resistance and raise blood glucose levels, necessitating continued insulin administration and often requiring dose adjustments to prevent diabetic ketoacidosis. 1

Physiological Mechanism

• During acute illness, the body releases increased levels of counterregulatory hormones (cortisol, glucagon, catecholamines, growth hormone) that directly increase insulin requirements 1
• These hormones promote insulin resistance and stimulate hepatic glucose production, leading to hyperglycemia even when food intake is reduced 2
• In type 1 diabetes, this metabolic stress increases the risk of diabetic ketoacidosis if insulin is discontinued or inadequately dosed 1

Critical Management Principle

• The need for insulin continues during acute illness—insulin should never be stopped, even if the patient is not eating 1
• Many patients with type 2 diabetes who do not normally require insulin will need supplemental insulin during periods of stress or illness 1, 3

Specific Illness Management Guidelines

Monitoring Requirements

• Test blood glucose frequently during illness (more often than usual) 1
• Test blood or urine for ketones, particularly if blood glucose exceeds 240 mg/dL 1
• Drink adequate amounts of fluid to prevent dehydration 1

Carbohydrate Intake During Illness

• Ingest 150-200 grams of carbohydrate daily (45-50 grams every 3-4 hours) to prevent starvation ketosis while making insulin adjustments 1
• Carbohydrate intake is especially important if blood glucose falls below 100 mg/dL (5.5 mmol/L) 1
• This carbohydrate provision, combined with medication adjustments, helps maintain glucose in the target range 1

Common Pitfalls to Avoid

• Never discontinue insulin during illness based on reduced food intake alone—this is the most dangerous error and can precipitate diabetic ketoacidosis in type 1 diabetes 1
• Do not assume that nausea, vomiting, or inability to eat means insulin should be stopped; insulin requirements typically remain elevated or increase during these conditions 3
• Establish a "sick day plan" with your physician before illness occurs, as insulin requirements may change unpredictably 3

Factors That Increase Insulin Requirements

• Infections and febrile illnesses 3
• Nausea and vomiting (despite reduced oral intake) 3
• Concurrent medications including oral contraceptives, corticosteroids, and thyroid replacement therapy 3
• Surgical stress and critical illness 4, 5

When to Seek Medical Attention

• Report ketone test results to your physician as instructed 3
• Contact your healthcare provider if blood glucose remains persistently elevated despite usual insulin doses 3
• Seek immediate care if unable to maintain adequate fluid intake or if ketones are moderate to large 1