(Blogitorials are short, informal blogs that are written in the spirit of a tweetorial).
Stress hyperglycemia is an everyday occurrence in the ICU, but we hardly know how to treat it.
I've been waiting years for this topic to be clarified… but I've realized that such clarity will probably never be reached.
Why?
The traditional evidence-based medicine model requires two things:
- (#1) A reasonably homogeneous group of patients who can be studied.
- (#2) An intervention that can be reproducibly performed across different hospitals.
When it comes to stress hyperglycemia, both of these things are missing.
(#1) Homogeneous patients to study: Optimal glycemic control almost certainly depends on the patient's baseline glycemic control (e.g., non-diabetic vs. diabetic). Within these rough categories, significant variation exists (e.g., a patient with hemoglobin A1C of 8% vs. 12%). Other variables also affect the ideal glycemic control strategy (e.g., underlying disease process, nutritional strategy). To date, most seminal studies have ignored these variables.
(#2) An intervention that can be reproduced across different hospitals: Studies and reviews focus solely on the glycemic target. However, this is only a small piece of the overall glycemic control strategy. The safety and efficacy of insulin therapy varies substantially across different institutions, due to minor details in treatment protocols (e.g., precisely how insulin infusions are titrated, whether glucose is checked from an arterial line versus a fingerstick, how long-acting insulin is utilized, etc.). Despite shooting for the same glucose target, different hospitals will achieve enormously different rates of glycemic variability and hypoglycemia.
So studies on stress hyperglycemia are effectively a Tower of Babel. Different interventions are being applied to different groups of patients with differing results. It's impossible to make an apples-to-apples comparison between studies. And applying these studies to real-world clinical practice is an even bigger leap of faith.
Where does this leave us clinically?
- The available evidentiary basis is shaky at best. It doesn't necessarily apply to our clinical practice.
- Insulin can definitely cause harm (hypoglycemic brain injury), whereas the benefits of tighter glycemic control are not robustly established.
- When in doubt we should be conservative with insulin, striving to avoid harm.
- We should avoid dogmatically applying any specific glycemic target to all patients. Every guideline recommends a specific target for glycemic control, but ironically these guidelines are not even consistent with each other:
That's it! For more on stress hyperglycemia see the IBCC.
Opening image: Photo by Rod Long on Unsplash
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