CHINA: A report published in Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy shows a strong link between Relative Hypoglycemia (RHG) and delirium in critically ill diabetic patients, as well as a correlation with death.
Relative hypoglycemia is a decrease in blood sugar greater than or equal to 30% below prehospital admission levels (estimated by hemoglobin A1C) but not to absolute hypoglycemia levels. Relative hypoglycemia is experienced when hypoglycemic symptoms are present with blood sugars above 70 mg/dL.

Delirium, a prevalent neurological condition marked by a change in cognition and a disturbance of consciousness, is frequently noticed in patients in intensive care units (ICU). Those with premorbid diabetes who are critically unwell may experience relative hypoglycemia (RHG), which is a drop below the goal range for normal blood glucose (BG). But little research or analysis has been done on these occurrences.
The purpose of the study was to investigate the prevalence and clinical importance of relative hypoglycemia (RHG) episodes in critically sick diabetic patients.
In this investigation, at least 12 BG recordings from patients with a history of diabetes who spent longer than three days in the intensive care unit (ICU) were retrospectively included. A single RHG incident was defined as a BG level that was more than 30% below the patient's hemoglobin A1c measurement at admission's approximated average. Subjects with and without RHG episodes had their outcomes compared. The final analysis comprised 113 patients in total.
Key highlights of the study:
In 73 patients (64.6%), RHG was identified.
RHG episodes were substantially associated with a greater prevalence of ICU delirium in those who had these.
A greater risk of 28-day death was also seen in them, but this was not statistically significant.
The risk of overall mortality was considerably higher for patients who experienced more RHG episodes (57.1% for more than four events vs. 15.4% for three to four events, P=0.006 and 15.1% for one to two events, P=0.003).
The researchers concluded that "relative hypoglycemia (RHG) is a frequent observation in critically ill diabetic patients and is related with mortality and the onset of delirium."
To ascertain the advantages of lowering relative hypoglycemia (RHG) episodes with a more flexible and personalized glucose target, they recommended additional prospective studies.
REFERENCE
Hui Zhao, Hua-Liang Ying, Chao Zhang & Shaohua Zhang (2022) Relative Hypoglycemia is Associated with Delirium in Critically Ill Patients with Diabetes: A Cohort Study, Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy, 15:, 3339-3346, DOI: 10.2147/DMSO.S369457