What are the adult hyperglycemia diagnosis and management guidelines using mmol/L units?

Guidelines for Hyperglycemia Management (mmol/L)

Diagnostic Criteria for Diabetes Mellitus

Diabetes is diagnosed when fasting plasma glucose ≥7.0 mmol/L on two separate occasions, or 2-hour post-load glucose ≥11.1 mmol/L during oral glucose tolerance test, or random plasma glucose ≥11.1 mmol/L with classic symptoms. 1

• Fasting plasma glucose ≥7.0 mmol/L measured on two different days confirms diabetes 1
• 2-hour plasma glucose ≥11.1 mmol/L after 75g oral glucose tolerance test is diagnostic 1
• Random plasma glucose ≥11.1 mmol/L with symptoms (polyuria, polydipsia, unexplained weight loss) confirms diabetes without need for repeat testing 1
• HbA1c ≥6.5% can also establish the diagnosis and should be confirmed with repeat testing unless unequivocal hyperglycemia is present 1, 2
• Measurement of fasting blood glucose is the recommended first-line screening test 1

Hyperglycemia Thresholds by Clinical Context

Stress Hyperglycemia (Perioperative/Acute Illness)

Stress hyperglycemia is defined as glucose ≥10.0 mmol/L in previously non-diabetic patients during acute illness or invasive procedures. 1

• Characterized by transient elevation to ≥10.0 mmol/L that resolves after stressor removal 1
• Represents an independent prognostic factor for morbidity and mortality 1
• Distinguish from pre-existing diabetes by checking HbA1c: if <6.5%, suggests stress-induced rather than chronic hyperglycemia 2

Type 2 Diabetes: Hyperosmolar Risk

In Type 2 diabetes, hyperglycemia >10.0 mmol/L with polyuria/glycosuria requires urgent assessment for hyperosmolar hyperglycemic state, especially if not compensated by adequate hydration. 1, 2

• Main acute risk is hyperosmolar hyperglycemic state when glucose >10.0 mmol/L 1
• This threshold is critical in unconscious patients or those unable to maintain adequate fluid intake 1

Glycemic Targets for Management

Outpatient/Ambulatory Targets

For Type 1 diabetes, target fasting plasma glucose 5–7 mmol/L on waking and 4–7 mmol/L before meals at other times, with postmeal glucose <9.0 mmol/L. 1

• Premeal capillary plasma glucose should be 4.4–7.2 mmol/L 1
• Peak postmeal glucose target is <10.0 mmol/L 1
• These targets should be individualized to avoid hypoglycemia 1

For Type 2 diabetes, aim for HbA1c <7% with individualized targets based on comorbidities and hypoglycemia risk. 1

Hospitalized Patients (Non-Critical)

For hospitalized non-critically ill patients, target premeal glucose <7.8 mmol/L and random glucose <10.0 mmol/L. 1, 2

• Premeal glucose target: <7.8 mmol/L 1
• Random glucose target: <10.0 mmol/L 1
• These targets apply to most hospitalized patients with non-critical illness 1

Critically Ill Patients (ICU)

In critically ill patients, avoid hyperglycemia >10.0 mmol/L and target blood glucose around 8.0 mmol/L (range 7–9 mmol/L). 1

• Target range of 7.8–10.0 mmol/L is appropriate for general ICU populations 1, 2
• More stringent targets (4.4–6.1 mmol/L) are not recommended due to hypoglycemia risk 1
• More liberal targets (10.0–11.1 mmol/L) should be avoided 1
• Specific populations (cardiovascular surgery, head trauma) may have different optimal ranges 1

Treatment Approach by Diabetes Type

Type 1 Diabetes: Mandatory Insulin

All Type 1 diabetes patients require basal-bolus insulin therapy with basal insulin never discontinued, even with normal glucose, to prevent diabetic ketoacidosis. 1, 2

• Basal insulin (long or intermediate-acting) must be supplied constantly, representing ~50% of daily requirements 1
• Ultra-rapid insulin analogues (5-minute onset) should be used for prandial coverage 1, 2
• Regular insulin is no longer recommended due to delayed action (20 minutes vs. 5 minutes) and prolonged duration (6 hours vs. 3 hours) 1
• Never stop basal insulin even if glucose is normal—cessation leads to ketoacidosis within hours 1, 2
• If hypoglycemia occurs, reduce basal dose modestly but maintain continuous coverage 1, 2

Type 2 Diabetes: Escalating Therapy

Type 2 diabetes initially managed with oral agents; insulin should be initiated when oral therapies no longer control glycemic levels. 1, 2

• First-line: oral glucose-lowering drugs, with metformin preferred 2
• GLP-1 receptor agonists may be added but can cause gastroparesis due to delayed gastric emptying 1
• Insulin indicated when glucose remains >10.0 mmol/L despite oral agents 1
• Insulin and oral agents can be safely combined 1

Acute Hyperglycemic Crisis Management

For diabetic ketoacidosis, start IV regular insulin at 0.1 units/kg/h after initial fluid resuscitation with 0.9% saline at 15-20 mL/kg in the first hour. 3

• Confirm DKA with pH <7.3, bicarbonate <15 mEq/L, and moderate-to-large ketones 3
• Initial fluid replacement: 0.9% saline 15-20 mL/kg/h (approximately 1-1.5 L first hour for 70 kg adult) 3
• Regular insulin by continuous IV infusion at 0.1 unit/kg/h after fluid bolus 3
• Continue insulin at 0.05 unit/kg/h even when glucose normalizes, adding IV glucose to maintain 8.3–11.1 mmol/L until acidosis resolves 3
• Resolution criteria: glucose <11.1 mmol/L, bicarbonate ≥18 mEq/L, pH >7.3 3
• Transition to subcutaneous insulin with 1-2 hour overlap once DKA resolved 3

For hyperosmolar hyperglycemic state, use more aggressive fluid replacement (8-10 L deficit) and lower insulin doses (0.05-0.1 unit/kg/h). 3

Monitoring Requirements

Check capillary blood glucose hourly during acute hyperglycemic crisis and every 2-4 hours for electrolytes, renal function, and venous pH. 3

• Hourly glucose monitoring during acute phase 3
• Electrolytes, urea, creatinine, osmolality, venous pH every 2-4 hours 3
• Blood glucose should be measured at every routine clinical visit for all diabetic patients 2

Critical Pitfalls to Avoid

Never discontinue basal insulin in Type 1 diabetes—abrupt cessation precipitates rapid ketoacidosis even with normal glucose levels. 1, 2, 3

• Stress hyperglycemia (≥10.0 mmol/L) is an independent predictor of mortality and requires treatment even without established diabetes 1
• Overly aggressive glucose lowering in elderly or critically ill patients increases mortality risk through hypoglycemia 2
• Do not use sliding-scale insulin alone—it treats hyperglycemia reactively rather than preventively 3
• Confirm abnormal glucose values with venous plasma measurements, not capillary or continuous monitors alone 2