Inpatient Glycemic Control

Consequences

• hypoglycemia
  • catacholaminergic state (arrhythmias, cardiac events)
  • transient cognitive deficits (falls, aspiration)
  • mortality
• hyperglycemia
  • catabolic state
  • electrolyte and fluid imbalances

Glycemic Targets for Hospitalized Diabetics

Population	BG Target (mM)
Noncritically ill	preprandial: 5.0-8.0; random: < 10.0
Critically ill	6.0-10.0
Perioperatively (non-CABG)	5.0-10.0
Acute coronary syndrome	7.0-10.0
L&D	4.0-7.0

• consider lower targets if stable with Hx of successful tight outpatient glycemic control
• consider higher targets if terminally ill or with severe comorbidities
• modify antihyperglycemic therapy if BG < 3.9 unless easily explained (e.g. missed meal)

Glucose Monitoring

If indicated, then the frequency should be about:

• fating, AC, and HS if eating;
• q4-6 h if NPO or with continuous enteral feeding;
• q1-2 h if on continuous IV insulin or critically ill.

Consider monitoring on glucose-altering interventions (glucocorticoids, octreotide, parenteral or enteral nutrition, etc).

CBG may be inaccurate in critically ill due to peripheral hypoperfusion.

SC Insulin

Basal

• must continue in T1DM due to risk of DKA
• continue for insulin-dependent T2DM
• new basal insulin dose is about 0.2-0.4 u/kg/d, as either NPH Q12H or glargine/degludec/detemir

Bolus

• should be a rapid-acting insulin analogue (aspart, lispro, glulisine), approx 0.05-0.1 u/kg/day if starting new, or 1/6 of TDD each

Correctional

• used in addition to basal + bolus to titrate control
• dose may vary according to degree of insulin resistance
• should be the same type of insulin as the bolus
• can be used to start or bridge insulin therapy in T2DM with Q6H regular insulin, correct marked nocturnal hyperglycemia, etc.

IV Insulin

• Less preferred; used in ICU, NPO, DKA, HHS states
• Would require BG measurements Q1-2H
• Usually needs concurrent glucose (PO/IV) administration except in DKA/HHS
• Transition to SC insulin:
  • Give short/rapid/fast acting insulin 1-2 hours before D/C IV insulin
  • Give intermediate/long acting insulin 2-3 hours before D/C IV insulin
  • Extrapolate a safe initial dose of SC insulin from the previous 6-8 hours to the 24-hour TDD, and give 50-80% of this calculated TDD as basal.

NPO

• T1DM - continue basal insulin at 75-100% of current dose depending on control
• T2DM - continue basal insulin at 25-75% of current dose depending on control
• No prandial insulin, obviously

Oral Antihyperglycemics

• If PO status preserved, can consider cautiously continuing oral agents.
• Discontinue or hold these medications in the following circumstances:
  • NPO/unable to eat normally
  • Day of a procedure, can resume afterwards
  • (potentially) contrast administration
• as well, ideally hold the following regardless of PO status:
  • SGLT2i (risk of euglycemic DKA)
  • GLP1 agonist (risk of nausea)
• in specific scenarios, hold the following regardless of PO status:
  • metformin (renal failure - risk of lactic acidosis)
  • TZDs (heart failure)
  • sulfonylureas (acute coronary syndrome)

Corticosteroids

• Hyperglycemia develops in 20-50% of people without previous hx of DM on corticosteroids
• Consider monitoring BG for 48 hours after initiating steroids w/wo hx of DM
• Can be treated with basal-bolus regimen as above

References

1. Management of diabetes mellitus in hospitalized patients - UpToDate
2. Pocket Medicine - Sabatine
3. Diabetes Canada | Clinical Practice Guidelines - Chapter 16: In-hospital Management of Diabetes