Mythbuster: Glucose Levels Must be Below a “Safe” Threshold Before Discharge

Background: Anyone who works in the Emergency Department has seen patients brought in by EMS or sent from the clinic with a chief complaint of “high blood sugar.”  Now, we are not talking about patients with diabetic ketoacidosis, but just simple hyperglycemia. This is a common complaint with no real consensus on optimal blood glucose levels before safe discharge.

What They Did:

  • Single Center, Retrospective, Cohort Chart Review
  • Patients received care determined by the MD working (No actual intervention or protocolized care was followed)


  • Determine if there is an association between discharge glucose and 7-day adverse outcomes:
    • Diabetic Ketoacidosis (DKA)
    • Hyperosmolar Hyperglycemic State
    • Repeat ED visit for Hyperglycemia
    • Hospitalization for Any Reason


  • ≥18 years of age
  • Glucose Level ≥400 mg/dL at any point during visit


  • Admission to the Hospital
  • Type 1 DM
  • Chief complaint of Hypoglycemia


  • 566 Hyperglycemia ED Encounters Included
  • 7 Day Adverse Outcomes:
    • DKA: 2 patients (0.4%)
    • Hyperosmolar Hyperglycemic State: 0 patients (0%)
    • Return Visit for Hyperglycemia: 62 patients (13%)
    • Hospitalization: 36 patients (7%)
    • Death: 0 patients (0%)
  • Mean Glucose at Discharge:
    • With 7-Day Adverse Outcome: 317 mg/dL
    • Without 7-Day Adverse Outcome: 336 mg/dL
  • Seven-Day ED Visit for Hyperglycemia
    • Discharge Glucose Level >350 mg/dL: OR 0.69 (95% CI: 0.26 – 1.82)
    • Intravenous Fluids Received: OR 0.92 (95% CI 0.65 – 1.30)
    • Insulin Received: OR 0.99 (0.94 – 04)


  • Outcome measures were patient-oriented
  • Countywide ambulance records were reviewed to look for patient visits to other EDs
  • Only 71 patients (13%) lost to follow up
  • Interobserver agreement in this study was excellent


  • Abstractors not blinded to study outcomes, but data for the outcome of interest were collected before other data points
  • Retrospective study design causes some limitations such as incomplete values in the charts
  • Care wasn’t standardized. Why some patients got certain treatments prior to discharge was not clear from this trial


  • It is important to remember that the assumed rates of repeat ED visits for hyperglycemia and hospitalizations have no previous data.
  • This is the first investigation describing ED treatments and 7-day outcomes for patients with elevated blood glucose levels, not in DKA.
  • Treatment of hyperglycemia is not without risk. 9 patients (2%) developed iatrogenic hypoglycemia

Author Conclusion: “ED discharge glucose in patients with moderate to severe hyperglycemia was not associated with 7-day outcomes of repeat ED visit for hyperglycemia or hospitalization.  Attaining a specific glucose goal before discharge in patients with hyperglycemia may be less important than traditionally thought.”

Clinical Take Home Point: A more appropriate approach to simple hyperglycemia, may be ensuring appropriate outpatient follow up for long-term glycemic control, just as we currently do for asymptomatic hypertension, instead of reaching a “safe” glucose threshold before discharge.


  1. Driver BE et al. Discharge Glucose is Not Associated With Short-Term Adverse Outcomes in Emergency Department Patients With Moderate to Severe Hyperglycemia. Ann Emerg Med 2016; S0196 – 0644 (16): 30162 – 7. PMID: 27353284

For More Thoughts on This Topic Checkout:

Post Peer Reviewed By: Anand Swaminathan (Twitter: @EMSwami)

Cite this article as: Salim Rezaie, "Mythbuster: Glucose Levels Must be Below a “Safe” Threshold Before Discharge", REBEL EM blog, December 1, 2016. Available at:

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