Prognostic Serum Calcitonin Gene-Related Peptide Level Value in Patients Following Traumatic Brain Injury

<b>Background</b> Traumatic brain injury (TBI) is a significant cause of disability and death worldwide. It is important to have affordable and accessible biomarkers to assess the prognosis of patients. This study investigated the prognostic significance of calcitonin gene-related peptide (CGRP) serum levels in individuals with TBI. <b>Materials and Methods</b> In this cross-sectional analytical study, CGRP levels were measured at admission, 24 hours, and 1 week after hospitalization. Patients were divided into two groups based on the Glasgow Coma Scale (GCS) score at admission: patients with mild/moderate TBI (GCS 9-15) and patients with severe TBI (GCS score 3-8), and CGRP levels were compared between the two groups. <b>Results</b> A total of 102 patients with TBI were included. Higher levels of CGRP were observed in all three stages of measurement (at admission, 24 hours, and 1 week after hospitalization) in severe TBI patients. The occurrence of CGRP levels of 2 to 10 ng/L or higher than 10 ng/L in the mild/moderate and severe groups upon admission was 68.6 and 91%, respectively ( <i>p</i> < 0.001). Within 24 hours of hospitalization, a more significant decrease in CGRP levels to lower ranges (> 0.5 and 0.5-2 ng/L) was observed in mild/moderate TBI patients (51.5%) compared with the severe group (19.4%). As indicated by logistic regression analysis, increased CGRP levels were directly associated with a higher risk of severe TBI. <b>Conclusion</b> The increase in CGRP level is directly related to the risk of severe TBI. Investigating the ability of CGRP as an easy and accessible biomarker to predict the prognosis of TBI patients is recommended in future studies.