Management of Hyperglycaemia

1. Treatment Goals

• The ADA recommends targeting HbA1c < 7.0% in most patients. This level has been clearly shown to reduce microvascular complications (retinopathy, nephropathy, neuropathy). - Symptom to Diagnosis, 4th Ed.
• Intensive control (HbA1c < 6.5%) does not consistently reduce macrovascular events and may be harmful in older patients with established cardiovascular disease.
• Goals must be individualised - frail elderly patients, those with cognitive impairment, and those on insulin/complex regimens prioritise avoidance of hypoglycaemia over tight control.
• In patients with HbA1c > 9%, start with dual therapy. If HbA1c > 10%, consider combination injectable therapy from the outset.

HbA1c - Mean Plasma Glucose Correlation

2. Monitoring

• HbA1c: every 3 months when targets are not met or therapy is changing; every 6 months in stable patients at goal. Note that 50% of the HbA1c value reflects glycaemia in the month before measurement, 25% from days 30-60, and 25% from days 60-90.
• Home blood glucose monitoring (SMBG): Patients on multiple daily insulin doses should test fasting, pre-lunch, pre-dinner, and pre-bed. Those on basal-only insulin should test fasting each morning.
• Continuous glucose monitoring (CGM): Increasingly integrated with insulin pumps (sensor-augmented pump; hybrid closed-loop systems). - Washington Manual of Medical Therapeutics

3. Lifestyle Modification

• Weight loss: goal of at least 10% of body weight
• Diet modification: reduced caloric and carbohydrate intake; Mediterranean-type or low-glycaemic diets
• Exercise: at least 150 minutes/week of moderate-intensity activity - improves insulin sensitivity in skeletal muscle and reduces hepatic glucose output
• Best instituted with a certified diabetes educator or dietician

4. Pharmacological Treatment

Step 1 - Monotherapy

Step 2 - Dual Therapy (add to metformin if HbA1c target not met after ~3 months)

Based on cardiovascular outcome trials (CVOTs): GLP-1 receptor agonists should be considered first-line in patients with established CVD or stroke; SGLT2 inhibitors should be first-line in patients with heart failure or diabetic kidney disease. - Washington Manual of Medical Therapeutics

Step 3 - Triple Therapy

• Metformin + Sulfonylurea + TZD / DPP-4i / SGLT-2i / GLP-1 RA / Insulin
• Metformin + SGLT-2i + Sulfonylurea / TZD / DPP-4i / GLP-1 RA / Insulin
• Metformin + GLP-1 RA + Sulfonylurea / TZD / SGLT-2i / Insulin

Step 4 - Insulin Therapy

• Failure of oral/injectable agents to achieve glycaemic control
• Metabolic decompensation (DKA, HHS)
• Newly diagnosed with severe hyperglycaemia (HbA1c > 10%)
• Chronic kidney disease precluding other agents
• Pregnancy

• A typical regimen provides 50% basal + 50% bolus (prandial) insulin.
• Insulin pump (CSII) with CGM integration (hybrid closed-loop) is increasingly used, especially in T1DM.
• Absorption is fastest from the abdomen, then arm > buttocks > thigh.

5. Special Populations

6. Acute Hyperglycaemic Crises

Diabetic Ketoacidosis (DKA)

• Occurs in T1DM (and sometimes T2DM with precipitating illness)
• Management: IV fluid resuscitation (0.9% NaCl), insulin infusion (0.1 units/kg/h), potassium replacement (hyperkalaemia may mask total body K+ depletion; severe hypokalaemia can develop after insulin is started), correction of acidosis, identify and treat precipitant.

Hyperosmolar Hyperglycaemic State (HHS)

• Occurs in T2DM; typically blood glucose > 600 mg/dL, severe dehydration, no significant acidosis
• Management similar to DKA but with focus on gradual fluid replacement and lower-dose insulin (once fluids started); sodium correction must be done cautiously.

7. Perioperative Hyperglycaemia

• Perioperative hyperglycaemia is associated with increased morbidity and mortality.
• Target blood glucose of 140-180 mg/dL in most hospitalised/perioperative patients.
• Metformin should be withheld in patients with acute illness, surgery, or iodinated contrast imaging.
• Insulin infusion protocols are used for tight intraoperative control when indicated. - Barash's Clinical Anesthesia, 9th Ed.; Miller's Anesthesia, 10th Ed.

Key Evidence Updates (2025-2026)