Glucose and Lactate Levels at Admission as Predictors of In-hospital Mortality

Abstract

Objective Glucose and lactate levels in patients at the time of admission have been studied in diverse patient groups. Some studies suggest that elevated glucose levels at admission predict worse outcomes. Elevated Lactate levels have also been reported to be directly associated with increased mortality. We wanted to determine if the combination of admission glucose and lactate levels improves the predictability of inpatient mortality and length of stay (LOS). Methods This is a retrospective study. We included all adult patients admitted at an academic medical center from October 1, 2015 to September 30, 2016. We collected basic clinical information, including age, gender, admission glucose and lactate levels, LOS, and mortality. We separated outcomes based on glucose and lactate levels by dividing them into quartiles. We also stratified patients based on normal lactate (<2.0 mmol/L), high lactate (2.0-4.0 mmol/L), and very high lactate (>4 mmol/L) levels; and on normal glucose (60-140 mg/dl), high glucose (140-200 mg/dl), and very high glucose (>200 mg/dl) levels. Results A total of 5,436 adult patients were included in our study. The median age was 58 years, and 57% of the patients were male. The median LOS was 6 days, and the overall in-hospital mortality rate was 11%. When the patients were separated in quartiles based on admission glucose values, mortality was higher in the 4th quartile (≥173 mg/dL): 14.87%, probability value (p): <0.001. When the patients were separated in quartiles based on lactate levels, the mortality was higher in the 4th quartile (≥2.23 mmol/L): 21.95%, p: 0.001. When the patients were paired according to normal, high, or very high lactate and glucose levels, the groups that had higher mortality were as follows: normal glucose/very high lactate: 32.43%; high glucose/very high lactate: 34.04%; and very high glucose and very high lactate: 39.15%. The groups with very high glucose and very high lactate had increased odds of mortality when compared with the other groups (p: <0.001). Conclusions Admission glucose and lactate levels provide useful information in the estimation of inpatient mortality. The LOS was shortened in the groups with higher glucose, lactate, or both. The combination of glucose and lactate levels predicted mortality better than either value alone.