The Bitter and the Sweet: Relationship of Lactate, Glucose, and Mortality After Severe Blunt Trauma

BACKGROUND: Hyperglycemia is associated with mortality after trauma; however, few studies have simultaneously investigated the association of depth of shock and acute hyperglycemia. We evaluated lactate, as a surrogate measure for depth of shock, and glucose levels on mortality following severe blunt trauma. We hypothesize that measurements of both lactate and glucose are associated with mortality when considered simultaneously. METHODS: This is a retrospective cohort study at a single academic trauma center. Inclusion criteria are age 18-89 years, blunt trauma, injury severity score (ISS) >= 15, and transferred from the scene of injury. All serum blood glucose and lactate values were analyzed within the first 24 hours of admission. Multiple metrics of glucose and lactate were calculated: first glucose (Gluc(adm)) and lactate (Lac(adm)) at hospital admission, mean 24-hour after hospital admission glucose (Gluc(24-h)(Mean)) and lactate (Lac(24-h)(Mean)), maximum 24-hour after hospital admission glucose (Gluc(24-h)(Max)) and lactate (Lac(24-h)(Max)), and time-weighted 24-hour after hospital admission glucose (Gluc(24-h)(TW)) and lactate (Lac(24-h)(TW)). Primary outcome was in-hospital mortality. Multivariable logistic regression modeling assessed the odds ratio (OR) of mortality, after adjusting for confounding variables. RESULTS: A total of 1439 trauma patients were included. When metrics of both glucose and lactate were analyzed, after adjusting for age, ISS, and admission shock index, only lactate remained significantly associated with mortality: Lac(adm) (OR, 1.28; 95% confidence interval [CI], 1.13-1.44); Lac(24-h)(Mean) (OR, 1.86; 95% CI, 1.52-2.28); Lac(24-h)(Max) (OR, 1.39; 95% CI, 1.23-1.56); and Lac(24-h)(TW) (OR, 1.86; 95% CI, 1.53-2.26). CONCLUSIONS: Lactate is associated with mortality in severely injured blunt trauma patients, after adjusting for injury severity, age, and shock index. However, we did not find evidence for an association of glucose with mortality after adjusting for lactate.