Emergency department lactate is associated with mortality in older adults admitted with and without infections.
OBJECTIVE
Serum lactate values in the emergency department (ED) have been associated with mortality in diverse populations of critically ill patients. This study investigates whether serum lactate values measured in the ED are associated with mortality in older patients admitted to the hospital, both with and without infections.


METHODS
This is a retrospective cohort study performed at two urban teaching hospitals. The study population includes 1,655 older ED patients (age>or=65 years) over a 3-year period (2004-2006) who had serum lactate measured prior to admission. The presence or absence of infection was determined by review of International Classification of Diseases Ninth Revision (ICD-9) admission diagnosis codes. Mortality during hospitalization was determined by review of inpatient records. Mortality at 30 and at 60 days was determined using a state death registry.


RESULTS
In patients with infections, increasing serum lactate values of >or=2.0 mmol/L were linearly associated with relative risk (RR) of mortality during hospitalization (RR=1.9 to 3.6 with increasing lactate), at 30 days (RR=1.7 to 2.6), and at 60 days (RR=1.4 to 2.3) when compared to patients with serum lactate levels of <2.0 mmol/L. In patients without infections, a similar association was observed (RR=1.1 to 3.9 during hospitalization, RR=1.2 to 2.6 at 30 days, RR=1.1 to 2.4 at 60 days). In both groups of patients, serum lactate had a greater magnitude of association with mortality than either of two other commonly ordered laboratory tests, leukocyte count and serum creatinine.


CONCLUSIONS
Higher ED lactate values are associated with greater mortality in a broad cohort of admitted patients over age 65 years, regardless of the presence or absence of infection.
del Portal
Daniel A
DA
University of Pennsylvania School of Medicine, Department of Emergency Medicine, Philadelphia, PA, USA.
Shofer
Frances
F
Mikkelsen
Mark E
ME
Dorsey
Philip J
PJ
Gaieski
David F
DF
Goyal
Munish
M
Synnestvedt
Marie
M
Weiner
Mark G
MG
Pines
Jesse M
JM
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D003404:Creatinine / Q000097:blood; D016638:Critical Illness / Q000401:mortality; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D017052:Hospital Mortality; D006784:Hospitals, Teaching; D006786:Hospitals, Urban; D006801:Humans; D007239:Infections / Q000097:blood / Q000401:mortality; D019344:Lactic Acid / Q000097:blood*; D007958:Leukocyte Count; D008297:Male; D010343:Patient Admission / Q000706:statistics & numerical data*; D010414:Pennsylvania / Q000453:epidemiology; D011237:Predictive Value of Tests; D012372:ROC Curve; D012044:Regression Analysis; D012189:Retrospective Studies; D015983:Selection Bias; D016037:Single-Blind Method
D015415:Biomarkers; D019344:Lactic Acid; D003404:Creatinine