[The value of combination of the mortality in emergency department sepsis score and blood lactate level in the risk stratification of severe sepsis in the emergency department].

OBJECTIVE: To evaluate the combination of the mortality in emergency department sepsis (MEDS) score with blood lactate level in the risk stratification of patients with severe sepsis in the emergency department (ED).

METHODS: 665 adult patients with severe sepsis admitted from May 2011 to December 2012 in ED were found to be eligible for the study. MEDS score, acute physiology and chronic health evaluation II (APACHEII) score, and arterial blood lactate was determined, and the outcomes in 28 days were recorded. Logistic regression analysis was used to evaluate the relationship between each predictive factor score and prognosis. Each predictive factor was compared with the areas under the receiver operating characteristics (ROC) curve (AUC).

RESULTS: The mortality in 28 days was 34.6% in 665 patients. The mortality in group of MEDS score 12-27 was significantly higher than that group of MEDS score<12 [51.0% (156/306) vs. 20.6% (74/155), χ(2)=28.414, P=0.000]. In the meantime, APACHEII score and blood lactate level were also significantly higher in group of MEDS score 12-27 than those in group with MEDS score<12 [APACHEII score: 26.4±10.6 vs. 21.7±8.1, t=-3.555, P=0.002; lactate: 4.9 (2.3, 9.9) mmol/L vs. 3.9 (1.5, 8.9) mmol/L, Z=-2.352, P=0.023]. Kaplan-Meier survival analysis showed significant difference in the two groups (the Log Rank test 36.71, P<0.01). The levels of 3 predictive factors were predominantly higher in non-survivors than survivors [MEDS score: 14.1±6.7 vs. 8.2±4.5, t=-6.929, P=0.000; APACHEII score: 28.1±7.1 vs. 22.2±11.3, t=-6.472, P=0.000; lactate: 5.4 (2.9, 11.0) mmol/L vs. 3.8 (1.2, 9.1) mmol/L, t=-6.472, P=0.004]. The AUCs were 0.813, 0.706 and 0.727 for MEDS score, APACHEII score and blood lactate respectively. The predictive ability for 28-day mortality of MEDS score was better than blood lactate (P=0.008) and APACHEII score (P=0.005). The AUC of MEDS score combined with lactate was 0.865, and 28-day mortality prediction was better than MEDS score (AUC 0.865 vs. 0.813, P<0.001). The sensitivity (83.1%), specificity (93.2%), positive prediction value (PPV, 62.4%), and negative prediction value (NPV, 92.1%) for MEDS score combined with lactate were highest among all predictors.

CONCLUSIONS: MEDS score combined with lactate is a good risk stratification tool for emergency patients with severe sepsis, and its prognostic capability is better than either MEDS score, APACHEII score or blood lactate.