Association Between Glycemic Gap and Mortality in Critically Ill Patients with Diabetes

Abstract

Objectives: Dysglycemia is pervasive and associated with poor outcomes in critically ill patients. Hyperglycemia, hypoglycemia and blood glucose fluctuation might all affect the outcomes, but appropriate level of blood glucose is uncertain especially in patients with diabetes regarding to the situation of glucose control before hospitalization. This study was aimed to investigate the effect of difference between mean blood glucose during ICU stay and level of blood glucose prior to admission to ICU upon outcomes of critically ill patients with diabetes.Method: This retrospective study undertaken in a 24-bed intensive care unit(ICU). Patients with diabetes expected to stay for more than 24hs were enrolled, HbA1c was tested within 3 days after admission and converted to the A1C-derived average glucose (ADAG) by the equation: ADAG = [ ( HbA1c * 28.7 ) – 46.7 ] * 18-1, arterial blood glucose measurements were fourth per day routinely during the first 7 days after admission, the mean glucose level(MGL) and SOFA (within 3 days, 5 days and 7days) were calculated for each person, GAPadm and GAPmean was calculated as admission blood glucose and MGL minus ADAG respectively, the incidence of moderate hypoglycemia(MH), severe hypoglycemia (SH), total dosage of glucocorticoids and average daily dosage of insulin within 7 days, duration of renal replacement therapy(RRT), ventilator-free hours and non-ICU stay days within 28 days were also collected. Patients enrolled were divided into survival group and non-survival group according to survival or not at 28-day, compare GAPadm and GAPmean between the two groups and explore the relationship between GAP and mortality in these critically ill patients.Results: 431 patients were enrolled and divided into survival group (n=256) and non-survival group (n=175). It was shown that two groups had comparable level of HbA1c, the non-survivors had greater APACHE II, SOFA, GAPadm, GAPmean-3, GAPmean-5, GAPmean-7 and higher MH and SH incidences. Less duration of ventilator-free, non-ICU stay and longer duration of RRT were recorded in non-survival group, of whom received less carbohydrates intake, higher insulin daily dosage and glucocorticoid dosage. GAPmean-5 had the greatest predictive power with AUC of 0.807(95%CI: 0.762-0.851), the cut-off value was 3.6mmol/L(sensitivity 77.7% and specificity 76.6%). The AUC was increased to 0.852(95%CI: 0.814-0.889) incorporated with SOFA5 (NRI = 11.34%, P < 0.001 ). Conclusion: Glycemic GAP between mean level of blood glucose especially MGL within 5 days after admission to ICU and A1C-derived average glucose was independently associated with 28-day mortality of critically ill patients with diabetes. The predictive power was optimized with addition of the top level of SOFA within 5 days.

Association Between Glycemic Gap and Mortality in Critically Ill Patients with Diabetes

“…21 The conclusion above impelled us to implement a more rational and effective protocols to monitor and control blood glucose to avoid or balance the two extremes which were “uncontrolled hyperglycemia” and “over tightly controlled glucose. 22…”

“…21 The conclusion above impelled us to implement a more rational and effective protocols to monitor and control blood glucose to avoid or balance the two extremes which were "uncontrolled hyperglycemia" and "over tightly controlled glucose. 22 Tangible proof convinced researchers of the fact that hyperglycemia of critically ill patients could not totally attribute to stress response. 23 It makes researchers turn to the relationship between the degree of premorbid glycaemia and mortality, the admission blood glucose levels are especially proved associated with higher mortality.…”

Effect of glycemic gap upon mortality in critically ill patients with diabetes

“…This might be the reason why studies fail to replicate the benefit of tight glycemic control on ICU mortality 36 . The above conclusion leads us to implement a more rational and effective protocol to monitor and control the level of blood glucose to avoid or balance the two extremes which are ‘uncontrolled hyperglycemia’ and ‘over tightly controlled glucose’ 37 . Therefore, hypoglycemia may indicate the severity of acute illnesses and it seems prudent to prevent long‐lasting hypoglycemia as much as possible by frequent and accurate blood glucose measurements and by the use of a proper insulin protocol with safe and rational blood glucose range.…”

Blood glucose-related indicators are associated with in-hospital mortality in critically ill patients with acute pancreatitis

“…Although Glucose_max reflects the patient’s acute response under stress, if the Glucose_max value is in the abnormal range, then blood glucose management is ineffective 22 . An increasing number of studies have proven that strengthening blood sugar control can reduce the in-hospital mortality risk of patients 23 – 25 . According to our prediction, the overall trend of the correlation between Glucose_max and in-hospital mortality should be similar to that between Glucose_mean and in-hospital mortality; however, because the number of patients who had Glucose_max levels in the hypoglycemic range in this study was extremely small, it only showed an upward trend.…”