Date Published: January 24, 2017
Publisher: Public Library of Science
Author(s): Konstantin A. Krychtiuk, Maria C. Honeder, Max Lenz, Gerald Maurer, Johann Wojta, Gottfried Heinz, Kurt Huber, Walter S. Speidl, Petter Bjornstad.
Critically ill patients admitted to a medical intensive care unit exhibit a high mortality rate irrespective of the cause of admission. Besides its role in fluid and electrolyte balance, vasopressin has been described as a stress hormone. Copeptin, the C-terminal portion of provasopressin mirrors vasopressin levels and has been described as a reliable biomarker for the individual’s stress level and was associated with outcome in various disease entities. The aim of this study was to analyze whether circulating levels of copeptin at ICU admission are associated with 30-day mortality.
In this single-center prospective observational study including 225 consecutive patients admitted to a tertiary medical ICU at a university hospital, blood was taken at ICU admission and copeptin levels were measured using a commercially available automated sandwich immunofluorescent assay.
Median acute physiology and chronic health evaluation II score was 20 and 30-day mortality was 25%. Median copeptin admission levels were significantly higher in non-survivors as compared with survivors (77.6 IQR 30.7–179.3 pmol/L versus 45.6 IQR 19.6–109.6 pmol/L; p = 0.025). Patients with serum levels of copeptin in the third tertile at admission had a 2.4-fold (95% CI 1.2–4.6; p = 0.01) increased mortality risk as compared to patients in the first tertile. When analyzing patients according to cause of admission, copeptin was only predictive of 30-day mortality in patients admitted due to medical causes as opposed to those admitted after cardiac surgery, as medical patients with levels of copeptin in the highest tertile had a 3.3-fold (95% CI 1.66.8, p = 0.002) risk of dying independent from APACHE II score, primary diagnosis, vasopressor use and need for mechanical ventilation.
Circulating levels of copeptin at ICU admission independently predict 30-day mortality in patients admitted to a medical ICU.
Different pathologies may trigger critical illness in patients requiring admission to an intensive care unit. Despite the fact that the causative underlying conditions are quite heterogeneous and novel technical developments in critical care medicine such as monitoring tools and transient organ replacement were introduced, prognosis remains poor. Reliable biomarkers predicting patient outcome irrespective of the underlying disease are scarce.
In this single-center, prospective observational study including 225 critically ill patients admitted to a medical ICU, patients who died within 30 days after ICU admittance showed significantly higher circulating copeptin levels as compared to those who survived. When stratified according to tertiles of circulating copeptin levels, patients in the highest tertile exhibited a 2.4-fold increased risk of dying within 30 days when compared to the patients in the first tertile.