Identifying Diabetes and Impaired Glucose Tolerance in ICU Patients

Diabetes is one of the most common comorbidities among patients admitted to the intensive care unit. Previous studies have found that patients with diabetes are at higher risk of severe complications including infections, delayed wound healing, cardiovascular events and ultimately death while in the ICU.

In the Netherlands, patients admitted to the ICU are classified as having diabetes based on whether their medical records indicate glucose management medication use (Dutch National Intensive Care Evaluation (NICE) Registry). However, this approach does not identify patients with 1) undiagnosed diabetes, 2) uncontrolled diabetes, 3) patients managing their condition through lifestyle modifications, or 4) individuals with prediabetes, which is considered an early stage of diabetes. Consequently, this may lead to an underestimation of the prevalence of chronic dysglycaemia among ICU patients. Therefore, the "true" prevalence and impact of various glycaemic states in ICU patients and how they influence acute and long-term outcomes remain underexplored. Within the general Dutch population, diabetes is diagnosed in 7% of individuals, while approximately 30% of those aged over 45 have prediabetes. In the ICU, 17% of admitted patients require medication for diabetes management, highlighting a higher prevalence compared to the general population's 7%. Given that most patients (\~87%) admitted to the ICU are older than 45 years, it is likely that the prevalence of prediabetes is elevated in ICU patients as well. It is essential to avoid underestimating the incidence of diabetes and impaired glucose tolerance to ensure that patients are managed properly during ICU stay and importantly after leaving the ICU. Diabetes diagnosis typically relies on (fasting) glucose levels yet diagnosing diabetes in ICU patients poses challenges due to stress and acute illness impacting blood glucose levels, leading to stress-induced hyperglycaemia. The investigators found that upon admission to the ICU, 77% of patients without diabetes exhibited high blood glucose levels, with 20% of these patients experiencing severe hyperglycaemia. The underlying cause of this hyperglycaemia is currently uncertain, but it may stem from acute critical illness, the effect of medications, previously undiagnosed diabetes or prediabetes, or a combination of these factors.

Since the investigators are currently unable to accurately determine if patients entering the ICU have diabetes or prediabetes using standard glucose measurements, measuring glycated haemoglobin (HbA1c) which reflects the average blood glucose levels over the past two or three months may be an alternative method which together with anthropometric, glycaemic parameters, and other metabolic traits will assist in assessing the risk of associated complications and the impact on organ injury. Given the rising incidence of diabetes in the general population, there is an increasing likelihood that a greater number of individuals will be admitted to the ICU with diabetes and prediabetes in the coming years. Moreover, the prevalence and impact of various glycaemic states in ICU patients and how they influence acute critical illness outcomes remain underexplored.