How should I manage a 40-year-old woman with type 2 diabetes on a ketogenic low-carbohydrate diet who has refused her diabetes medication for three months and now has an HbA1c of 13.5%?

Management of a 40-Year-Old Woman with Type 2 Diabetes, HbA1c 13.5%, on Ketogenic Diet, Refusing Medications

This patient requires immediate insulin therapy regardless of her dietary preferences; an HbA1c of 13.5% represents severe, uncontrolled hyperglycemia that places her at imminent risk for diabetic ketoacidosis, hyperosmolar hyperglycemic state, and irreversible microvascular complications.

Immediate Assessment and Risk Stratification

Check for diabetic ketoacidosis immediately by obtaining venous blood gases, serum electrolytes, blood urea nitrogen, creatinine, and urine ketones, because ketogenic diets combined with severe hyperglycemia create a perfect storm for euglycemic or hyperglycemic DKA 1. The combination of carbohydrate restriction and insulin deficiency dramatically increases ketone production 2, 3.

• Assess for DKA symptoms: polyuria, polydipsia, fatigue, Kussmaul respirations, altered mental status, nausea, or vomiting 1
• Measure serum β-hydroxybutyrate if available, as it is more accurate than urine ketones for detecting ongoing ketosis 4
• Obtain baseline fasting glucose, complete metabolic panel, lipid panel, and liver function tests 1

The ketogenic diet is contraindicated in this clinical scenario. While very low-carbohydrate diets may show modest short-term benefits in well-controlled type 2 diabetes 5, 6, 7, the American Diabetes Association explicitly states this approach is only appropriate for 3–4 months maximum and only when glycemic control is already adequate 5. At an HbA1c of 13.5%, she has severe hyperglycemia that requires pharmacologic intervention, not dietary manipulation alone.

Insulin Initiation Protocol

Start basal insulin immediately at 0.3–0.5 units/kg/day (approximately 18–30 units for a 60 kg woman), given as a single daily injection of long-acting insulin glargine or detemir 1, 8. For insulin-naïve type 2 diabetes patients, the FDA-approved starting dose is 0.2 units/kg or up to 10 units daily 8, but given her HbA1c of 13.5%, she requires the higher end of the dosing spectrum.

If She Refuses Insulin

Counsel her that at this HbA1c level, diet alone—even a ketogenic diet—cannot achieve adequate glycemic control. The evidence shows that while ketogenic diets can reduce HbA1c by 0.2–0.5% in controlled settings 5, she needs a reduction of approximately 6.5 percentage points to reach target. Research demonstrates that even intensive low-carbohydrate interventions in type 2 diabetes achieve HbA1c reductions from 8.9% to 5.6% only when combined with medication adjustments 6, 7.

Explain the immediate risks:

• Diabetic ketoacidosis can develop within days, especially on a ketogenic diet 2, 3
• HbA1c >9% is associated with exponentially increased microvascular complication risk 9
• At 13.5%, she is at risk for hyperosmolar hyperglycemic state, which carries 10–20% mortality 1

If She Accepts Insulin

Initiate basal-bolus insulin therapy because glucose levels corresponding to HbA1c 13.5% (estimated average glucose ~330 mg/dL) require both fasting and postprandial glucose control 1, 10:

• Basal insulin: Start glargine 20–25 units once daily (0.3–0.4 units/kg for a 60 kg woman) 8
• Prandial insulin: Add rapid-acting insulin 4–6 units before each meal if she resumes normal carbohydrate intake 1
• Titration: Increase basal insulin by 2–4 units every 3 days until fasting glucose reaches 80–130 mg/dL 1, 10

If she insists on continuing the ketogenic diet while on insulin:

• Reduce prandial insulin doses proportionally to carbohydrate intake (approximately 1 unit per 10–15 grams of carbohydrate) 1
• Monitor for hypoglycemia 4 times daily initially, as ketogenic diets increase insulin sensitivity 6
• Educate her to never stop basal insulin during illness or fasting, as this precipitates DKA 1

Monitoring Protocol

Daily fasting glucose checks are mandatory during the first 2–4 weeks of insulin titration 1, 10:

• Target fasting glucose: 80–130 mg/dL 1
• If fasting glucose ≥180 mg/dL, increase basal insulin by 4 units every 3 days 10
• If fasting glucose 140–179 mg/dL, increase by 2 units every 3 days 10

Check HbA1c in 3 months to assess treatment effectiveness 1. Given her starting HbA1c of 13.5%, expect a reduction of 2–3 percentage points in the first 3 months with adequate insulin therapy 9.

Monitor for ketosis weekly during the first month if she continues the ketogenic diet, using either urine ketone strips or serum β-hydroxybutyrate 4, 2. Persistent ketones >1.0 mmol/L warrant immediate medical evaluation 4.

Addressing the Ketogenic Diet

The American Diabetes Association states that ketogenic diets (<50 g carbohydrate/day) are only appropriate for short-term use (3–4 months) and only when desired by the patient with adequate glycemic control 5. This patient does not meet these criteria.

Counsel her to transition to a moderate carbohydrate intake (44–46% of total calories) once insulin therapy is initiated 5:

• This approach is sustainable long-term, whereas ketogenic diets show loss of benefit over time 5
• Moderate carbohydrate intake reduces the risk of euglycemic DKA 2, 3
• Individualize macronutrient distribution to her usual intake to increase adherence 5

If she refuses to modify the diet:

• Provide at least 150–200 grams of carbohydrate daily through liquid sources (juice, broth) to suppress starvation ketosis 4
• Warn her that the combination of ketogenic diet and insulin deficiency caused by medication refusal is the exact mechanism that triggers euglycemic DKA 2, 3

Common Pitfalls to Avoid

Do not delay insulin therapy in the hope that dietary modification alone will suffice. At HbA1c 13.5%, she has severe hyperglycemia that requires immediate pharmacologic intervention 5.

Do not use sliding-scale insulin alone without basal insulin coverage, as this achieves target glucose in only 38% of patients compared to 68% with proper basal-bolus therapy 10.

Do not attribute her hyperglycemia solely to dietary choices. An HbA1c of 13.5% after 3 months of a ketogenic diet indicates profound insulin deficiency that cannot be overcome by carbohydrate restriction alone 5, 6.

Monitor potassium closely if she develops DKA, as insulin therapy drives potassium intracellularly; never start insulin if serum potassium is <3.3 mEq/L 4.

Patient Education

Educate her that insulin is not a failure but rather a necessary tool to prevent blindness, kidney failure, neuropathy, and cardiovascular disease 9. The UKPDS demonstrated that every 1% reduction in HbA1c reduces microvascular complications by 37% 9.

Teach her to recognize hypoglycemia symptoms (shakiness, sweating, confusion, hunger) and always carry fast-acting carbohydrate (glucose tablets, juice) 5, 1.

Instruct her to maintain hydration with non-caloric fluids during illness and to contact medical care immediately if she develops nausea, vomiting, or persistent ketones 1.