Clinical implications of serum myoglobin in trauma patients: A retrospective study from a level 1 trauma center

BACKGROUND: We aimed to study the clinical implication of high serum myoglobin levels in trauma patients. METHODS: A retrospective analysis was conducted on data from trauma patients who were admitted to a level 1 trauma center between January 2012 and December 2015. A receiver operating characteristic (ROC) curve analysis was performed for the optimum myoglobin cutoff plotted against hospital length of stay of >1 week. Patients were divided into two groups (Group 1; low vs. Group 2; high myoglobin), and a comparative analysis was performed. RESULTS: There were 898 patients who met the inclusion criteria with a mean age of 35.9 ± 14.6 years. Based on ROC, the myoglobin optimum cutoff was 1000 ng/ml (64% of patients were in Group 1 and 36% in Group 2). The mean myoglobin level was 328 ng/ml in patients with the Injury Severity Score (ISS) <15 versus 1202 ng/ml in patients with ISS ≥15 (P < 0.001). Patients in Group 2 had higher ISS (22.2 ± 10 vs. 18.8 ± 10), more musculoskeletal injuries (18.3% vs. 4.2%), more blood transfusion (74% vs. 39%), intubation (57% vs. 46.5%), and sepsis (12% vs. 7.3%). The length of hospital stays was significantly higher in Group 2, but mortality was comparable. High myoglobin levels had a crude odd ratio 2.41; 95% confidence interval (1.470–3.184) for a longer hospital stay with a positive predictive value of 89% and a specificity of 77%. CONCLUSIONS: One-third of the admitted trauma patients have elevated serum myoglobin level, which is associated with the prolonged hospital stay. The discriminatory power of myoglobin value of 1000 in trauma is fair, and further prospective assessments are needed.