1. Overview & Pathophysiology
Hyperglycemia in the hospital setting is a strong predictor of adverse outcomes, including increased mortality, infection rates, and length of stay.
- Definition: In-hospital hyperglycemia is defined as any glucose value .
- Prevalence: Occurs in ~38% of hospitalized patients (26% known diabetes, 12% no prior history).
- Stress Hyperglycemia: Acute illness increases stress hormones (cortisol, catecholamines) and inflammatory cytokines, which increase insulin resistance and hepatic glucose production.
2. Screening & Diagnosis
Identifying undiagnosed diabetes is a key opportunity during admission.
- A1C Screening:
- Perform on admission for all patients with diabetes or hyperglycemia if not done in the past 3 months.
- Helps differentiate stress hyperglycemia from undiagnosed diabetes.
- Interpretation: An A1C is highly specific for diagnosing dysglycemia post-hospitalization.
- Monitoring Frequency:
- Eating: Before meals and at bedtime.
- NPO/Enteral Feeds: Every 4–6 hours.
- IV Insulin/Critical Care: Every 1–2 hours.
3. Glycemic Targets
The guidelines distinguish between critically ill and non-critically ill patients.
| Patient Population | Glycemic Target (mmol/L) | Notes |
| Non-Critically Ill | Preprandial: 5.0 – 8.0 Random: < 10.0 | Applies to the majority of medical/surgical patients.
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| Critically Ill | 6.0 – 10.0 | Avoid < 6.0 to minimize mortality/hypoglycemia risk.
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| CABG (Intraoperative) | 5.5 – 11.1 | Continuous IV insulin preferred to reduce sternal wound infections.
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| Perioperative (General) | 5.0 – 10.0 | For minor/moderate surgeries.
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4. Pharmacologic Management
Insulin is the preferred agent for in-hospital management due to its safety, efficacy, and adjustability.
- Preferred Regimen: Basal + Bolus + Correction (Basal-Bolus-Supplemental).
- Basal: Long-acting (e.g., glargine, detemir) controls fasting/inter-meal glucose.
- Bolus: Rapid-acting (e.g., aspart, lispro) covers meals.
- Correction: Rapid-acting covers hyperglycemia above target.
- Discouraged Regimen: Correction-only (Sliding Scale) insulin alone is strongly discouraged as it results in “reactive” management and poorer control.
- Insulin Naïve: Start 0.4–0.5 units/kg/day (50% basal, 50% bolus).
B. Critically Ill (Intravenous Insulin)
- Indication: Critically ill, NPO, or hyperglycemic emergencies (DKA/HHS).
- Protocol: Continuous IV insulin infusion targeting 6.0–10.0 mmol/L.
- Transitioning IV to SC:
- Calculate Total Daily Dose (TDD) based on the last 6–8 hours of stable IV requirements.
- Give 60–80% of this extrapolated dose as SC basal insulin.
- Overlap: Administer SC basal 2–3 hours (or rapid 1–2 hours) before stopping the IV drip to prevent rebound hyperglycemia.
C. Non-Insulin Agents
Oral agents (e.g., metformin, sulfonylureas) are often discontinued due to contraindications like renal variation, contrast dye exposure, or irregular eating.
5. Special Clinical Situations
Enteral & Parenteral Nutrition:
- Parenteral (TPN): Insulin can be added to the TPN bag (Regular insulin) or given SC.
- Enteral (Tube Feeds):
- Continuous: Basal insulin or longer-acting insulin (NPH) helps match the continuous carb load.
- Bolus Feeds: 50% Basal / 50% Bolus (divided to match feed times).
Corticosteroid Therapy:
- Steroids cause significant insulin resistance and postprandial hyperglycemia.
- Management: Basal-Bolus-Correction is superior to sliding scale. NPH may be used to match the steroid profile.
- Monitoring: Monitor BG for at least 48 hours after starting high-dose steroids.
Self-Management & Pumps (CSII):
- Patients who are mentally competent and physically able may continue self-management (including pumps) if hospital policy permits.
- Requirements: Must utilize a flowsheet, provide own supplies, and demonstrate competency (e.g., changing sets, calculating bolus).
6. Diabetes Canada Clinical Practice Guidelines Recommendations
- Screening: Measure A1C on admission for all with diabetes (if not done in 3 months) and those with new hyperglycemia [Grade D/C].
- Monitoring: Individualize frequency; usually AC+HS for eating, q4-6h for NPO/Enteral, q1-2h for IV insulin [Grade D].
- Preferred Therapy: Use proactive Basal-Bolus-Correction insulin rather than correction-only (sliding scale) [Grade A, Level 1A].
- Targets:
- Non-Critically Ill: 5.0–8.0 mmol/L (preprandial) [Grade D].
- Critically Ill: < 10.0 mmol/L and > 6.0 mmol/L [Grade B/D].
- CABG: Use IV insulin to target 5.5–11.1 mmol/L intraoperatively to reduce infection risk [Grade A, Level 1A].
- Safety: Implement nurse-initiated hypoglycemia protocols (including glucagon) [Grade D].
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