The effect of blood glucose variability on the survival of patients in the intensive care unit: a prospective observational study

Although hypoglycemia and hyperglycemia are common in patients in the intensive care unit (ICU) and may negatively impact treatment outcomes, glycemic variability has recently gained attention as a promising risk factor in these patients. This study investigated the impact of hypoglycemia, hyperglycemia and glycemic variability on the outcomes of ICU patients. Daily blood glucose levels measured for the study participants were classified as within the reference range of 110-180 mg/dL or outside the reference range at <110 mg/dL or >180 mg/dL. Glycemic variability was classified as a fluctuation in daily blood glucose levels by >70 mg/dL. These measurements were standardized by dividing the number of daily blood glucose levels and glycemic variability outside the reference range by the number of daily levels within the reference range, which yielded the glycemic ratio (GR) and delta ( increment )-glucose ratio ( increment GR), respectively, and were compared between survivors and non-survivors. A total of 358 patients were prospectively assessed in this study. Our results showed that GR was 0.74 in survivors and 1.04 in non-survivors (p: 0.002), whereas increment GR was 0.73 in survivors and 1.0 in non-survivors (p < 0.001). Additionally, the mortality rates were 54.4% and 30.6% for patients with an overall mean increment glucose >70 mg/dL and <70 mg/dL (p < 0.001), respectively. Altogether, an increase in overall mean increment glucose, increment GR and GR resulted in an increased mortality risk in hypoglycemic and hyperglycemic ICU patients.