Relationship of early Hyperglycemia to mortality in trauma patients

Introduction: Recent randomized prospective data suggest that early hyperglycemia is associated with excess mortality in critically ill patients, and tight glucose control leads to improved outcome. This concept has not been carefully examined in trauma patients, and the relationship of early hyperglycemia to mortality from sepsis in this population is unclear. The objective of this study was to determine the relationship different levels of early blood glucose elevation to outcome in a trauma ICU population. Methods: The records of all patients admitted to the ICU over a 2-year period at a Level I trauma center were reviewed for age, injury severity scores (ISS), admission Glasgow Coma Scale (GCS) score, base deficit (BD), blood glucose, and mortality. Three possible cutoffs in defining hyperglycemia were examined (glucose greater than or equal to 110 mg/dL, greater than or equal to 150 mg/dL, greater than or equal to200 mg/dL) in relation to infection and mortality. Early hyperglycemia was defined as elevated blood glucose on hospital days I or 2. Those with diabetes mellitus were excluded. Results From 1/00-12/01, 516 eligible patients were admitted to the ICU after injury. Early hyperglycemia occurred in 483 at the greater than or equal to 110 mg/dL level, 311 at the greater than or equal to 150 mg/dL level, and 90 patients at the greater than or equal to 200 mg/dL level. Univariate logistic regression demonstrated a significant relationship between ISS and subsequent infection(p = 0.02) and a trend toward such a relationship in GCS score, glucose greater than or equal to 150 mg/dL, and glucose greater than or equal to 200 mg/dL (p = 0.06, 0.12, and 0.06). A similar analysis for the relationship of these variables to eventual mortality showed a significant correlation with all examined variables except glucose greater than or equal to 110 mg/dL. Multiple logistic regression to control for the effect of age, ISS, GCS score, and BD found early glucose greater than or equal to 200 mg/dL to be an independent predictor of both infection and mortality while no such relationship was found with greater than or equal to 110 mg/dL or greater than or equal to 150 mg/dL. Conclusion: Early hyperglycemia. as defined by glucose greater than or equal to 200 mg/dL is associated with significantly higher infection and mortality rates in trauma patients independent of injury characteristics. This was not true at the cutoffs of greater than or equal to 110 mg/dL or greater than or equal to 150 mg/dL. These data support the need for a prospective analysis of tight glucose control, keeping serum glucose < 200 mg/dL in critically ill trauma patients. However, aggressive maintenance of levels <110 mg/dL as reported by others may not be necessary.