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Table 3 Multivariable Cox proportional hazards model for the identification of independent variables associated with in-hospital death

From: The prognostic value of blood lactate levels relative to that of vital signs in the pre-hospital setting: a pilot study

Variable Start model Final model
  HR 95% CI p value HR 95% CI p value
Δ ln(lactate) T1 to T2* 0.20 0.05 to 0.79 0.022 0.20 0.05 to 0.76 0.018
SBP T1 per mmHg 1.00 0.99 to 1.01 0.56 Not in model   0.87
Heart rate T1 per beat/minute 1.01 0.99 to 1.02 0.47 Not in model   0.66
GCS T1 per unit 0.93 0.87 to 0.99 0.034 0.93 0.88 to 0.99 0.022
  1. The variables were simultaneously entered in the model (start model). A backward elimination method was used to construct the final model.
  2. * Δ ln(lactate) T1 to T2: for every 63% decrease (100*(1-(1/e)) = 63%) of the lactate level at T2 relative to the level at T1, the hazard of death decreased by 80% (100 (1-HR)) in the final model (95% CI = 24 to 95%). e = 2.71828, GCS = Glasgow Coma Scale, HR = hazard ratio, ln = natural logarithm, SBP = systolic blood pressure, T1 = on arrival of the ambulance on the scene, T2 = just before or on arrival at the emergency department.