How should diabetes be managed in a hospitalized adult, including insulin regimens, oral medication adjustments, and discharge planning?

Management of Diabetes in Hospitalized Adults

For non-critically ill hospitalized adults with diabetes, use scheduled basal-bolus insulin (basal, prandial, and correction components) for patients with good nutritional intake, targeting blood glucose 100-180 mg/dL, and avoid sliding scale insulin alone. 1, 2

Glycemic Targets

The target blood glucose range for most hospitalized patients is 100-180 mg/dL (5.6-10.0 mmol/L) 1, 2. This applies to both critically ill and non-critically ill patients. More stringent targets (110-140 mg/dL) may be appropriate for select stable patients with prior tight control, while less stringent targets (up to 250 mg/dL) may be acceptable in terminally ill patients or those with severe comorbidities 2.

Insulin Regimens by Clinical Scenario

Patients Already on Insulin at Home

Continue the scheduled insulin regimen, modified for nutritional status and illness severity 1. Key adjustments:

• Reduce basal insulin by 10-20% if on "basal-heavy" regimens (≥0.6-1.0 units/kg/day) where basal insulin inappropriately covers meals 1
• Maintain the basal-bolus structure but adjust doses based on current intake and glucose monitoring

Patients NOT on Insulin at Home (Diet or Oral Medications)

Start with correctional insulin alone for mild hyperglycemia (BG >140 mg/dL) 1. If persistent hyperglycemia occurs (≥2 point-of-care glucose measurements ≥180 mg/dL in 24 hours), add scheduled insulin therapy 1.

For confirmed admission glucose ≥180 mg/dL, initiate scheduled insulin immediately 1.

Patients with Good Oral Intake

Use basal-bolus insulin regimen (basal + prandial + correction insulin) 2, 1. This is the preferred approach and superior to correction-only insulin 2, 3. The basal-bolus regimen:

• Provides 50% of total daily dose as basal insulin (once daily)
• Divides remaining 50% as prandial insulin across three meals
• Adds correction doses before meals as needed

Patients with Poor/No Oral Intake (NPO)

Use basal insulin plus correction insulin only 2, 1. Do not give prandial insulin when patients are NPO. Monitor glucose every 4-6 hours and administer correction doses with short- or rapid-acting insulin 4, 3.

Patients on Enteral Nutrition

Use NPH-based or basal-bolus regimens 1. Adjust insulin timing to match continuous vs bolus feeding schedules.

Patients on Corticosteroids

Use prandial insulin (often NPH) for once-daily steroids 4. For long-acting glucocorticoids like dexamethasone or continuous use, add long-acting basal insulin to control fasting glucose. High-dose steroids often require extraordinary amounts of prandial and correctional insulin in addition to basal 4.

Oral Diabetes Medications in Hospital

Scheduled insulin therapy is preferred over noninsulin therapies for most hospitalized patients with hyperglycemia 1. However:

• Metformin: Withhold on day of surgery 4. Despite concerns about lactic acidosis, it can be used safely in many hospitalized patients with normal kidney function, though guidelines recommend caution 5
• Sulfonylureas: Withhold the morning of surgery 4
• DPP-4 inhibitors: May be considered in stable patients with mild-to-moderate hyperglycemia as alternative to complex insulin regimens 6
• GLP-1 receptor agonists: Limited data on perioperative safety and delayed gastric emptying 3
• SGLT-2 inhibitors: Generally avoided due to DKA risk in acute illness

Perioperative Management

Target blood glucose 80-180 mg/dL (4.4-10.0 mmol/L) perioperatively 4, 3. Stricter targets do not improve outcomes and increase hypoglycemia risk 3.

Key perioperative steps:

• Withhold metformin on day of surgery 4
• Give 50-80% of long-acting insulin dose or half of NPH dose 4
• Reduce basal insulin by 25% the evening before surgery (better achieves targets with less hypoglycemia) 3
• Monitor glucose every 4-6 hours while NPO 4
• Use basal-bolus insulin for noncardiac general surgery (superior to correction-only insulin) 3

Critical Care Setting

Use continuous intravenous insulin infusion for critically ill patients 2, 7. Initiate when glucose persistently exceeds 180 mg/dL, targeting 140-180 mg/dL 2. Use validated protocols with predefined adjustment algorithms 2.

Monitoring

• Before meals for patients eating 2
• Every 4-6 hours for NPO patients 4, 2
• Every 30 minutes to 2 hours for IV insulin infusions 2
• Measure HbA1c at admission if none available from prior 3 months to guide discharge planning 4, 1

Critical Pitfall: Sliding Scale Insulin Alone

The use of sliding scale insulin (correction-only insulin) as sole therapy is strongly discouraged 8, 2. This reactive approach has no proven benefit, increases hypoglycemia risk, and causes large glucose fluctuations 5. Always add scheduled basal insulin for persistent hyperglycemia.

Hypoglycemia Management

Implement a hospital-wide, nurse-initiated hypoglycemia protocol 8. Common triggers include:

• Sudden corticosteroid dose reduction
• Reduced oral intake or unexpected NPO status
• Inappropriate timing of short-acting insulin relative to meals
• Interruption of enteral/parenteral nutrition 7

Document and track all hypoglycemic episodes 8.

Discharge Planning

Begin discharge planning at admission and provide structured, individualized plans 4, 2. This reduces length of stay, readmission rates, and improves satisfaction 4, 7.

Essential Discharge Components

Medication reconciliation 4:

• Cross-check that no chronic medications were stopped
• Fill and review new prescriptions before discharge
• Ensure patient has access to medications and supplies

Diabetes education 1:

• Provide survival skills education (glucose monitoring, hypoglycemia recognition/treatment, nutrition basics)
• Use diabetes care and education specialists when available
• Prioritize high-risk patients: those admitted for diabetes complications, newly diagnosed, or newly starting insulin

Follow-up appointments 4:

• Schedule within 1 month for all patients with hyperglycemia in hospital
• Schedule within 1-2 weeks if glycemic medications changed or glucose control suboptimal at discharge
• Communicate clearly with outpatient providers about cause of hyperglycemia, complications, and recommended treatments

Discharge Regimen by Patient Type

Type 1 diabetes: Resume basal-bolus regimen at hospital doses 9. Follow-up timing based on HbA1c:

• HbA1c <8%: primary care at 1 month
• HbA1c 8-9%: endocrinology consultation
• HbA1c >9% or unstable glucose: endocrinology before discharge

Type 2 diabetes on oral agents only 9:

• HbA1c <8%: resume previous medications at same doses
• HbA1c 8-9%: add basal insulin (e.g., glargine) with protocol for dose adjustment
• HbA1c >9%: continue basal-bolus insulin, endocrinology consultation

Type 2 diabetes on insulin 9:

• HbA1c <8%: resume previous regimen after 48 hours (if creatinine clearance >30 mL/min for oral agents, >60 mL/min for metformin)
• HbA1c 8-9%: resume oral agents, continue basal insulin
• HbA1c >9%: continue basal-bolus insulin

Stress hyperglycemia (elevated glucose with HbA1c <6.5%) 9:

• Taper insulin as glucose normalizes
• No treatment at discharge
• Critical: 60% develop diabetes within one year—measure fasting glucose at 1 month, then annually

Carbohydrate Counting

For noninsulin-treated type 2 diabetes requiring prandial insulin: do not use carbohydrate counting 1. For type 1 diabetes or insulin-treated type 2 diabetes: either carbohydrate counting or fixed prandial dosing is acceptable 1. Carbohydrate counting requires hospital policies, trained staff, and may need ICR adjustments for illness 1.