Podcast Summary: AACE Podcasts

Episode 54: Safety and Efficacy of Insulins in Critically Ill Patients Receiving Continuous Enteral Nutrition

Release Date: December 13, 2024
Host: Dr. Vinh Tang Preacha
Guest: Dr. Cecilia Lo Wang, Professor of Medicine, University of Colorado

Episode Overview

This episode tackles the nuanced management of insulin therapy in critically ill patients who are receiving continuous enteral (tube) nutrition. Dr. Cecilia Lo Wang joins the podcast to discuss her recent research on the safety and efficacy of various insulin regimens in this challenging inpatient cohort. The conversation focuses on practical challenges, current practices, study results, and actionable takeaways for clinicians managing hyper- and hypoglycemia in this setting.

Key Discussion Points and Insights

The Challenge of Glycemic Management in Tube-Fed Critically Ill Patients

• High Prevalence of Hyperglycemia: Nearly half of patients—whether or not they have diabetes—develop hyperglycemia with enteral feeds, as tube feeding is a highly non-physiologic, continuous method of nutrient delivery.
  (03:00) Dr. Lo Wang: "Almost half of people with or without diabetes can develop hyperglycemia when they are placed on enteral nutrition, which is a very non physiologic way of eating, especially when it's continuous.")

• Frequent Feed Interruptions: Both planned (procedures, medication administration) and unplanned (tube dislodgement, intolerance) interruptions are common, making stable insulin dosing complex.
  (02:00-03:00)

• Risk of Hypo- and Hyperglycemia: Without tailored insulin regimens, patients are at significant risk for both over- and under-treatment.

Overview of Insulin Strategies in the Hospital

• No Standardized Insulin Approach: Unlike other aspects of inpatient care, there are no universally accepted protocols for insulin regimens in patients on continuous tube feeds.

• Common Hospital Regimens Studied:

  • 70/30 Human Insulin (NPH/Regular) every 8 hours + Correctional Rapid Insulin q4h
  • Basal-Bolus Regimen: Long-acting insulin (glargine or detemir) + Rapid-acting insulin correction q4h
  • Rapid-acting Insulin Only q4h (07:00-08:00)

• Adjustment Practices: Highly variable; adjustments are often up to the provider and may not be made consistently, sometimes falling behind other pressing clinical concerns.
  (10:12, Dr. Lo Wang: "I think that in the long list of different problems that patients are facing ... sometimes glucose falls to the bottom.")

Study Design and Key Findings

• Population: 475 critically ill inpatients on continuous enteral feeds, with or without diabetes, cared for in 2019.
• Endpoints: Glucose time-in-range (70-180mg/dL), hypoglycemia, and hyperglycemia rates.
• Results:
  • Long-acting and intermediate-acting (70/30) regimens were both safe and effective.
    (12:00-13:30, Dr. Lo Wang: "Both long acting and intermediate acting regimens were efficacious and safe ... compared with those on the rapid-acting regimen.")
  • Rapid-acting only regimens underperformed, with more time spent outside target glucose ranges.
  • 70/30 every 8 hours performed at least as well as basal-bolus regimens, possibly with less hypoglycemia.
  • Patients without diabetes fared better overall; average glucose was lower than in those with diabetes.

Clinical Implications and Takeaways

• No International Standard: There’s wide practice variation and no prevailing standard or guideline.
  (17:00, Host: "So are you saying there is no international standard at all?" Dr. Lo Wang: "No.")

• Need for a Basal Component: Regimens lacking basal insulin (i.e., rapid-acting alone) are suboptimal.
  (13:00, Host: "The rapid acting regimen isn't providing any sort of basal at all.")

• Intermediate-acting Regimens (70/30) Are Reasonable Options: This approach may balance efficacy and safety, especially given the unpredictable nature of tube feeding schedules.
  (18:41, Host: "I kind of like the 7030 every eight hours that seems to be not too long of insulin but enough to cover the carb load.")

• Importance of Daily Review: Regular, at least daily, reassessment and adjustment of insulin is critical due to frequent changes in patient status and nutrition delivery.
  (19:47, Dr. Lo Wang: "One of the key points is to assess the regimens, assess the glucose control daily and sometimes even more often than that to keep our patients within the goal ranges.")

Outpatient vs. Inpatient Considerations

• Hospital management allows for frequent (even overnight) insulin dosing, which is impractical in the outpatient setting (e.g., cystic fibrosis with nocturnal feeds).
• Bolus feeding is more physiological but not always tolerated in critically ill patients. (04:37-06:33)

Notable Quotes and Memorable Moments

• On the challenge of insulin timing:
  Dr. Lo Wang (01:57):

  "The difficulty is that we really don't have a standard way of delivering insulin...one of the ways that we could manage this is with basal bolus regimens. And the problem is that if the basal insulin is adjusted for continuous tube feeds...then when there's planned and unplanned interruptions, patients can become quite hypoglycemic."

• On lack of guidelines:
  Dr. Lo Wang (17:03):

  "If you read the consensus statements and...the clinical practice guidelines by the professional societies on inpatient management of hyperglycemia, there's really no strong recommendation either way."

• On study findings and clinical practice:
  Dr. Lo Wang (18:53):

  "What this study kind of reassured us, although of course there are many limitations...is that 7030 is no worse and maybe better than basal bolus."

• On the need for daily adjustments:
  Dr. Lo Wang (19:47):

  "A key point is to assess the regimens, assess the glucose control daily and sometimes even more often than that to keep our patients within the goal ranges."

Timestamps for Important Segments

• 01:05: Dr. Lo Wang introduces herself and her clinical role
• 01:57 – 04:13: Discussion of challenges with insulin management and tube feeding interruptions
• 04:37 – 06:33: Different tube feeding regimens (continuous vs. bolus vs. cyclic; inpatient vs. outpatient)
• 07:06 – 09:40: Study methodology and hospital insulin regimens explained
• 11:54 – 13:45: Key findings: comparison of regimens; patient demographics
• 15:16 – 18:53: Discussion of previous related studies; nuanced analysis of 70/30 vs. basal bolus
• 17:00 – 17:45: Current state of international and national guidelines
• 19:47 – 20:30: Dr. Lo Wang's clinical takeaways for listeners

Key Takeaways for Clinicians

• Critically ill patients on continuous tube feeds are at major risk for both hypo- and hyperglycemia; lack of standardized insulin regimens remains a challenge.
• Both intermediate-acting (70/30) every 8 hours and long-acting basal bolus regimens are effective and relatively safe; rapid-acting-only approaches are less effective.
• Insulin regimens must be re-evaluated daily, and even more often if glycemic control is not within target.
• Large, prospective studies are needed to further clarify optimal insulin strategy in this population.