Relationship between glycated hemoglobin, Intensive Care Unit admission blood sugar and glucose control with ICU mortality in critically ill patients

Background and Aims: The association between hyperglycemia and mortality is believed to be influenced by the presence of diabetes mellitus (DM). In this study, we evaluated the effect of preexisting hyperglycemia on the association between acute blood glucose management and mortality in critically ill patients. The primary objective of the study was the relationship between HbA(1)c and mortality in critically ill patients. Secondary objectives of the study were relationship between Intensive Care Unit (ICU) admission blood glucose and glucose control during ICU stay with mortality in critically ill patients. Materials and Methods: Five hundred patients admitted to two ICUs were enrolled. Blood sugar and hemoglobin A(1)c (HbA(1)c) concentrations on ICU admission were measured. Age, sex, history of DM, comorbidities, Acute Physiology and Chronic Health Evaluation II score, sequential organ failure assessment score, hypoglycemic episodes, drug history, mortality, and development of acute kidney injury and liver failure were noted for all patients. Results: Without considering the history of diabetes, nonsurvivors had significantly higher HbA(1)c values compared to survivors (7.25 +/- 1.87 vs. 6.05 +/- 1.22, respectively, P < 0.001). Blood glucose levels in ICU admission showed a significant correlation with risk of death (P < 0.006, confidence interval [CI]: 1.004-1.02, relative risk [RR]: 1.01). Logistic regression analysis revealed that HbA(1)c increased the risk of death; with each increase in HbA(1)c level, the risk of death doubled. However, this relationship was not statistically significant (P: 0.161, CI: 0.933-1.58, RR: 1.2). Conclusions: Acute hyperglycemia significantly affects mortality in the critically ill patients; this relation is also influenced by chronic hyperglycemia.