Fibrinogen is an independent predictor of mortality in major trauma patients: A five-year statewide cohort study

Abstract

Introduction: Fibrinogen may be reduced following traumatic injury due to loss from haemorrhage, increased consumption and reduced synthesis. In the absence of clinical trials, guidelines for fibrinogen replacement are based on expert opinion and vary internationally. We aimed to determine prevalence and predictors of low fibrinogen on admission in major trauma patients and investigate association of fibrinogen levels with patient outcomes.

Patients and methods: Data on all major trauma patients (January 2007-July 2011) identified through a prospective statewide trauma registry in Victoria, Australia were linked with laboratory and transfusion data. Major trauma included any of the following: death after injury, injury severity score (ISS) >15, admission to intensive care unit requiring mechanical ventilation, or urgent surgery for intrathoracic, intracranial, intra-abdominal procedures or fixation of pelvic or spinal fractures. Associations between initial fibrinogen level and in-hospital mortality were analysed using multiple logistic regression.

Results: Of 4773 patients identified, 114 (2.4%) had fibrinogen less than 1g/L, 283 (5.9%) 1.0-1.5g/L, 617 (12.9%) 1.6-1.9g/L, 3024 (63.4%) 2-4g/L and 735 (15%) >4g/L. Median fibrinogen was 2.6g/L (interquartile range 2.1-3.4). After adjusting for age, gender, ISS, injury type, pH, temperature, Glasgow Coma Score (GCS), initial international normalised ratio and platelet count, the lowest fibrinogen categories, compared with normal range, were associated with increased in-hospital mortality (adjusted odds ratio [OR] for less than 1g/L 3.28 [95% CI 1.71-6.28, p<0.01], 1-1.5g/L adjusted OR 2.08 [95% CI 1.36-3.16, p<0.01] and 1.6-1.9g/L adjusted OR 1.39 [95% CI 0.97-2.00, p=0.08]). Predictors of initial fibrinogen <1.5g/L were younger age, lower GCS, systolic blood pressure <90mmHg, chest decompression, penetrating injury, ISS >25 and lower pH and temperature.

Conclusions: Initial fibrinogen levels less than the normal range are independently associated with higher in-hospital mortality in major trauma patients. Future studies are warranted to investigate whether earlier and/or greater fibrinogen replacement improves clinical outcomes.

Keywords: Coagulopathy; Fibrinogen; Haemorrhage; Transfusion; Trauma.