title: Absolute lactate value vs relative reduction as a predictor of mortality in severe sepsis and septic shock.
abstract: Lactate reduction, a common method of risk stratification, has been variably defined. Among patients with an initial lactate >4mmol/L, we compared mortality prediction between a subsequent lactate ≥4mmol/L to a <10% and <20% decrease between initial and subsequent lactate values.
  
  
  
  We performed a single-center retrospective study of patients presenting to the emergency department with an initial lactate ≥4mmol/L and suspected infection. Patients were stratified by lactate reduction using 3 previously identified definitions (subsequent lactate ≥4mmol/L, and <10% and <20% relative decrease in lactate) and compared using multivariable logistic regression. Sensitivity and specificity were compared using McNemar test.
  
  
  
  A subsequent lactate ≥4mmol/L and a lactate reduction <20% were associated with increased in-hospital mortality (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.24-8.16; P=.02 and OR, 3.11; 95% CI, 1.39-6.96; P=.006, respectively), whereas a lactate reduction <10% was not (OR, 1.13; 95% CI, 0.94-1.34; P=.11). A subsequent lactate ≥4mmol/L and a lactate reduction <20% were more sensitive than a lactate reduction <10% (72% vs 41%, P=.002 and 62% vs 41%, P=.008, respectively) but less specific (57% vs 76%, P<.001 and 67% vs 76%, P=.002, respectively).
  
  
  
  A subsequent lactate ≥4mmol/L and lactate reduction <20% were associated with increased in-hospital mortality, whereas a lactate reduction <10% was not. Sensitivity and specificity are different between these parameters.
authors: Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA; Massachussetts Institute of Technology, Cambridge, MA; Department of Medicine, Division of Pulmonary and Critical Care, University of Washington, Seattle, WA. Electronic address: slokhand@uw.edu.
authors: Sharukh
authors: S
authors: Lokhandwala
authors: Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, MA; Department of Anesthesiology, Aarhus University Hospital, Aarhus, Denmark; Research Center for Emergency Medicine, Aarhus University Hospital, Aarhus, Denmark. Electronic address: lwanders@bidmc.harvard.edu.
authors: Lars W
authors: LW
authors: Andersen
authors: Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA. Electronic address: ssnair@bidmc.harvard.edu.
authors: Sunil
authors: S
authors: Nair
authors: Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, MA. Electronic address: pvpatel@bidmc.harvard.edu.
authors: Parth
authors: P
authors: Patel
authors: Harvard Medical School, Boston, MA; Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, MA; Department of Anesthesia Critical Care, Division of Critical Care, Beth Israel Deaconess Medical Center, Boston, MA. Electronic address: mcocchi@bidmc.harvard.edu.
authors: Michael N
authors: MN
authors: Cocchi
authors: Harvard Medical School, Boston, MA; Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, MA; Department of Medicine, Division of Pulmonary and Critical Care, Beth Israel Deaconess Medical Center, Boston, MA. Electronic address: mdonnino@bidmc.harvard.edu.
authors: Michael W
authors: MW
authors: Donnino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood*; D003422:Critical Care; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000097:blood / Q000401:mortality*; D012772:Shock, Septic / Q000097:blood / Q000401:mortality
chemical_list: D015415:Biomarkers; D019344:Lactic Acid
keywords: Lactate; Mortality; Sensitivity; Sepsis; Specificity