AUTHOR=Bou Chebl Ralphe , Jamali Sarah , Mikati Nancy , Al Assaad Reem , Abdel Daem Karim , Kattouf Nadim , Safa Rawan , Makki Maha , Tamim Hani , Abou Dagher Gilbert
TITLE=Relative Hyperlactatemia in the Emergency Department
JOURNAL=Frontiers in Medicine
VOLUME=7
YEAR=2020
URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2020.00561
DOI=10.3389/fmed.2020.00561
ISSN=2296-858X
ABSTRACT=Objective: The clinical interpretation of lactate ≤ 2.00 mmol/L in emergency department (ED) patients is not well-characterized. This study aims to determine the optimal cutoff value for lactate within the reference range that predicts in-hospital mortality among ED patients.
Methods: This was a retrospective study of adult patients presenting to a tertiary ED with an initial serum lactate level of <2.00 mmol/L. The primary outcome was in-hospital mortality. Youden's index was utilized to determine the optimal threshold that predicts mortality. Patients above the threshold were labeled as having relative hyperlactatemia.
Results: During the study period, 1,638 patients were included. The mean age was 66.9 ± 18.6 years, 47.1% of the population were female, and the most prevalent comorbidity was hypertension (56.7%). The mean lactate level at presentation was 1.5 ± 0.3 mmol/L. In-hospital mortality was 3.8% in the overall population, and 16.2% were admitted to the ICU. A lactate level of 1.33 mmol/L was found to be the optimal cutoff that best discriminates between survivors and non-survivors. Relative hyperlactatemia was an independent predictor of in-hospital mortality (OR 1.78 C1.18–4.03; p = 0.02). Finally, relative hyperlactatemia was associated with increased mortality in patients without hypertension (4.7 vs. 1.1%; p = 0.008), as well as patients without diabetes or COPD.
Conclusion: The optimal cutoff of initial serum lactate that discriminates between survivors and non-survivors in the ED is 1.33 mmol/L. Relative hyperlactatemia is associated with increased mortality in emergency department patients, and this interaction seems to be more important in healthy patients.