Diabetes Management in the Acute Care Setting

Adil Abbasi, MD

Introduction

Diabetes mellitus is a common comorbidity among hospitalized patients, whether they are admitted for a diabetes-related illness or another acute condition. The physiological stress of acute illness, surgery, infection, trauma, or medication changes can significantly alter glycemic control, even in individuals without a prior diagnosis of diabetes (Umpierrez et al., 2012). Optimal inpatient glucose management is critical, as both hyperglycemia and hypoglycemia are independently associated with increased morbidity, mortality, and length of hospital stay (American Diabetes Association [ADA], 2024).

Pathophysiology and Risks

Acute illness triggers a complex hormonal response that includes increased levels of counter-regulatory hormones such as cortisol, catecholamines, glucagon, and growth hormone. These changes lead to increased gluconeogenesis, glycogenolysis, and insulin resistance, making glycemic control more difficult (Draznin et al., 2021). Hospitalized patients may also receive medications that impact glucose (e.g., steroids, vasopressors, parenteral nutrition), have altered nutrition (NPO status, enteral or parenteral feeding), and fluctuating renal or hepatic function.

Risks of Poor Glycemic Control:

• Hyperglycemia increases risk for infection, impaired wound healing, polyneuropathy, and mortality.
• Hypoglycemia increases risk of neurologic injury, falls, arrhythmia, and mortality.
• Glycemic variability itself is a risk factor for adverse outcomes.

Glycemic Targets:

General Targets (Non-critical care):

• Pre-meal glucose: 100–140 mg/dL
• Random glucose: <180 mg/dL

Critically Ill Patients (ICU):

• Target glucose range: 140–180 mg/dL
• Avoid: Glucose <110 mg/dL, or persistent >180 mg/dL

Tighter control (110–140 mg/dL) may be appropriate in selected patients, but increases risk of hypoglycemia and is generally not recommended (ADA, 2024; NICE-SUGAR Study, 2009).

Insulin Therapy: Mainstay of Inpatient Management

Insulin is the preferred agent for glucose management in most hospitalized patients, regardless of prior outpatient therapy, because of its potency, flexibility, and rapid titratability.

Types of Insulin Therapy

1. Basal–Bolus Regimen (Preferred for most non-ICU patients)

• Basal insulin: Maintains baseline glucose (e.g., glargine, detemir)
• Nutritional (prandial) insulin: Covers carbohydrate intake with meals (e.g., lispro, aspart, regular)
• Correction (supplemental/“sliding scale”) insulin: Corrects unexpected hyperglycemia

2. Sliding Scale Insulin (SSI) Alone

• Reactive approach: Uses only correction insulin
• Inferior outcomes compared to basal–bolus; higher risk of both hyper- and hypoglycemia
• Acceptable only for very short-term management (e.g., NPO, perioperative) or those with very mild hyperglycemia

3. IV Insulin Infusion (Critically ill/ICU, DKA, HHS)

• Allows tight titration and rapid adjustment
• Requires frequent (hourly) blood glucose monitoring

Oral Agents

• Generally avoided in acute care due to variable absorption, risk of hypoglycemia, renal/hepatic contraindications, and drug–drug interactions.
• Metformin should be held due to risk of lactic acidosis in the setting of renal dysfunction, sepsis, hypoxia, or contrast administration.
• SGLT2 inhibitors and other agents are held due to risk of ketoacidosis, dehydration, and infection.

Special Clinical Scenarios

NPO (Nothing by Mouth)

• Hold prandial (nutritional) insulin.
• Continue basal insulin at 60–80% of usual dose (to prevent ketosis/hyperglycemia).
• Use correction insulin every 4–6 hours.

Enteral/Parenteral Nutrition

• Adjust insulin regimen to match feeding schedule (e.g., regular insulin every 6 hours for continuous feeds, rapid-acting insulin with bolus feeds).
• Increased frequency of monitoring due to risk of hypoglycemia if feeds interrupted.

Steroid-induced Hyperglycemia

• Glucose can rise rapidly; consider intermediate-acting insulin (e.g., NPH) to match steroid peak.
• May require significant temporary dose escalation.

Acute Kidney or Liver Dysfunction

• Decreased insulin requirements (reduced clearance).
• Increased risk of hypoglycemia; adjust doses downward and monitor closely.

Monitoring

• Point-of-care (POC) blood glucose: Before meals and at bedtime (q4–6h if NPO or on enteral feeds; hourly if on IV insulin).
• Continuous glucose monitoring is emerging but not yet standard in acute care.

Hypoglycemia Management

• Definition: Blood glucose <70 mg/dL (severe <54 mg/dL)
• Immediate treatment: 15–20g oral glucose if able, IV dextrose if not
• Monitor and repeat every 15 minutes until >70 mg/dL, then provide snack/meal if able.
• Investigate cause and adjust insulin regimen.

Key Clinical Pearls

• Always review trends—avoid making large changes based on a single value.
• Assess for secondary causes (infection, medication changes, renal function, missed doses).
• Discharge planning: Reassess regimen, provide education, coordinate follow-up care.
• Special populations: Elderly, cognitive impairment, renal/hepatic dysfunction—use more conservative targets and regimens.

Summary

• Hyperglycemia and hypoglycemia both increase morbidity and mortality in hospitalized patients.
• Insulin is the preferred agent; basal–bolus regimens are superior to sliding scale alone.
• Usual targets: 140–180 mg/dL for most; avoid hypoglycemia at all costs.
• Oral agents are generally held; resume if appropriate at discharge.
• Adjust insulin in the setting of NPO status, enteral/parenteral feeds, steroids, renal/hepatic dysfunction.
• Frequent blood glucose monitoring is essential.
• Immediate action is needed for hypoglycemia (<70 mg/dL).
• Individualize therapy based on comorbidities, cognitive status, and risk factors.

References

1. American Diabetes Association (ADA). (2024). Standards of Medical Care in Diabetes—2024. Diabetes Care, 47(Supplement_1): S217–S229. Link
2. Draznin, B., et al. (2021). Management of Hyperglycemia in Hospitalized Patients in Non-critical Care Setting: An Endocrine Society Clinical Practice Guideline. The Journal of Clinical Endocrinology & Metabolism, 106(12), 3655–3670.
3. Umpierrez, G. E., & Pasquel, F. J. (2012). Management of Inpatient Hyperglycemia and Diabetes in Older Adults. Diabetes Care, 35(2), 260–268.
4. NICE-SUGAR Study Investigators. (2009). Intensive versus conventional glucose control in critically ill patients. N Engl J Med, 360(13), 1283–1297.

Comparison Table of Inpatient Insulin Regimens

Clinical Case Examples

Case 1: Medical Floor – Patient Eating Regular Diet

Patient: 65-year-old male with type 2 diabetes admitted for pneumonia. Eating regular diet.
Home regimen: Metformin and glipizide (both held on admission).

Order:

• Start basal-bolus regimen:

• Glargine 20 units SQ at bedtime (basal)
• Lispro 6 units SQ before each meal (prandial)
• Correctional lispro per protocol before meals and at bedtime (e.g., 1 unit for every 25 mg/dL >150 mg/dL)

• Blood glucose checks before meals and at bedtime

Course:
BG runs 160–200 after meals, 120–150 fasting. Adjust prandial insulin up by 2 units per meal. Monitor for hypoglycemia.

Key teaching point:
Basal-bolus regimen with correction is preferred for most patients eating in the hospital. Oral agents usually held.

Case 2: NPO for Procedure

Patient: 74-year-old woman with T2DM, on glargine 32 units nightly at home, NPO after midnight for surgery.

Order:

• Hold prandial insulin
• Give 60–80% of usual basal (e.g., glargine 20–24 units)
• Blood glucose q4–6h
• Correction insulin per protocol if BG >140

Course:
Fasting BG remains 120–160. No hypoglycemia. Resume full regimen when eating restarts.

Key teaching point:
Do not stop basal insulin completely in NPO patients; reduce dose to lower risk of hypoglycemia.

Case 3: ICU – Septic Shock (Critically Ill, IV Insulin)

Patient: 56-year-old man, newly diagnosed DM, in septic shock, intubated, on pressors, TPN.

Order:

• Start regular insulin IV infusion per hospital protocol (e.g., initial rate 2 units/hr, titrate hourly)
• Target BG 140–180 mg/dL
• Monitor BG every hour
• Transition to subcutaneous regimen when stable and oral intake resumed

Key teaching point:
IV insulin infusions provide rapid, precise control but require intensive monitoring. Titration per protocol.

Case 4: Steroid-Induced Hyperglycemia

Patient: 70-year-old woman, no history of diabetes, started on prednisone 60 mg for COPD exacerbation. BG now 200–250 mg/dL.

Order:

• Initiate NPH insulin 0.1–0.2 units/kg AM (covers daytime steroid effect)
• Blood glucose before lunch/dinner and at bedtime
• Add correction insulin as needed

Key teaching point:
Steroids cause postprandial/daytime hyperglycemia—use intermediate-acting insulin to match steroid profile.

Case 5: ESRD (End-Stage Renal Disease)

Patient: 68-year-old male with insulin-dependent diabetes, ESRD on dialysis, now hospitalized for infection.

Order:

• Decrease all insulin doses by 25–50% (decreased clearance)
• Frequent BG monitoring (before/after dialysis)
• Watch for hypoglycemia, especially post-dialysis

Key teaching point:
Renal failure reduces insulin clearance; adjust doses downward and monitor closely.

References

1. American Diabetes Association (ADA). (2024). Standards of Medical Care in Diabetes—2024. Diabetes Care, 47(Suppl 1): S217–S229. Link
2. Umpierrez, G.E., & Pasquel, F.J. (2012). Management of Inpatient Hyperglycemia and Diabetes in Older Adults. Diabetes Care, 35(2), 260–268.
3. Draznin, B., et al. (2021). Management of Hyperglycemia in Hospitalized Patients in Non-critical Care Setting: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab, 106(12), 3655–3670.