title: Emergency department lactate is associated with mortality in older adults admitted with and without infections.
abstract: 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.
authors.affiliation: University of Pennsylvania School of Medicine, Department of Emergency Medicine, Philadelphia, PA, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: del Portal
authors.forename: Frances
authors.initials: F
authors.lastname: Shofer
authors.forename: Mark E
authors.initials: ME
authors.lastname: Mikkelsen
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Dorsey
authors.forename: David F
authors.initials: DF
authors.lastname: Gaieski
authors.forename: Munish
authors.initials: M
authors.lastname: Goyal
authors.forename: Marie
authors.initials: M
authors.lastname: Synnestvedt
authors.forename: Mark G
authors.initials: MG
authors.lastname: Weiner
authors.forename: Jesse M
authors.initials: JM
authors.lastname: Pines
mesh_terms: 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
chemical_list: D015415:Biomarkers; D019344:Lactic Acid; D003404:Creatinine