Are People with Diabetes Immunocompromised?

What does it mean to be immunocompromised?

Simply put, the term “immunocompromised” means that the person’s immune system is not functioning properly to fight off infections. This could be due to a number of reasons, including underlying health conditions, or specific medications that the person is taking.

For example, patients who are HIV-positive are considered immunocompromised. This is because HIV invades the T cells (a type of white blood cell), which are a major component of our immune system. When functioning normally, T cells help to effectively clear various infections. Because HIV affects the T cells, the immune system of these patients may not respond as effectively, and they may struggle with complications from infections that most healthy people would easily recover from.

Similarly, some classes of medications can directly inhibit immune system responses. For instance, patients who are taking anti-rejection medications following an organ or tissue transplant are considered immunocompromised. This is also the case for patients who take immunosuppressive agents for other reasons, including for the treatment of certain autoimmune conditions and cancers.

Also, because immune system function is underdeveloped in very young children and declining in the very elderly, one may consider that the very young and the very old might be considered immunocompromised to a degree (because the immune system is not functioning quite as efficiently as it does in a healthy adult).

So, what about diabetes? Could diabetes, on its own, affect our immune system function to such a degree that would be considered “immunocompromised”? Are people with diabetes, by definition of just having the condition, immunocompromised?

It is known that high blood glucose levels can negatively affect immune system function, likely doing so through several mechanisms. High blood glucose levels are linked to negative clinical outcomes in the context of infections. The importance of maintaining optimal blood glucose management, and especially during infection and in the hospital setting, has been described in the scientific literature.

It is also well-established that patients with diabetes who achieve the recommended A1c levels have a markedly lowered risk for developing infections or complications from infections as compared to those with higher A1cs. You can read more about the connection between blood glucose levels and health complications here.

One expert commentary published in the Canadian Medical Association Journal explains,

“The evidence indicates that an immunocompromised state occurs only in the context of poor glycemic control with severe complications such as diabetic ketoacidosis or in adults with vasculopathy and peripheral neuropathy.”

There is some debate concerning the pathophysiology of both type 1 and type 2 diabetes as related to aberrant inflammatory responses and what this could mean for responses to certain infections. However, this is a complex and multifactorial topic, of which much remains to be elucidated at this time, and we cannot generalize based on theoretical and/or poorly characterized physiological processes in this patient population.

What is well-established, is that for patients who are able to maintain optimal glycemic management, and in the absence of other factors (such as related complications, a medication that may suppress immune system function), diabetes, on its own, does not make the patient automatically immunocompromised. However, for patients who frequently experience very high blood glucose levels and certain associated complications, immune system function can be negatively affected. This subset of patients might be considered “immunocompromised” due to the frequency and severity of hyperglycemia as compared to those with more optimal glycemic management and/or other complicating factors.

Also, it’s important to remember that when talking about an entire population of people with diabetes, on average, these patients are more likely to be immunocompromised. In addition to (generally) having higher than normal blood glucose levels for a considerable proportion of time, many people with diabetes are more likely to also have other health conditions that may negatively affect their immune system function. One example, in particular for patients with type 2 diabetes, is obesity, which is known to negatively impact immune function.

In summary, to accurately determine whether a patient with diabetes is “immunocompromised”, we must consider their overall health, including other health conditions, the medications that they use, as well as their age and glycemic management. Simply having diabetes does not, on its own, necessarily mean that the patient is immunocompromised, although as a group, this patient population is more likely to have immune system function issues.