One year outcome in mild to moderate head injury: the predictive value of acute injury characteristics related to complaints and return to work.

OBJECTIVES: To determine the prognostic value of characteristics of acute injury and duration of post-traumatic amnesia (PTA) for long term outcome in patients with mild to moderate head injury in terms of complaints and return to work.
METHODS: Patients with a Glasgow coma score (GCS) on admission of 9-14 were included. Post-traumatic amnesia was assessed prospectively. Follow up was performed at 1, 3, 6, and 12 months after injury. Outcome was determined by the Glasgow outcome scale (GOS) 1 year after injury and compared with a more detailed outcome scale (DOS) comprising cognitive and neurobehavioural aspects.
RESULTS: Sixty seven patients were included, mean age 33.2 (SD 14.7) years and mean PTA 7.8 (SD 7.3) days. One year after injury, 73% of patients had resumed previous work although most (84%) still reported complaints. The most frequent complaints were headache (32%), irritability (34%), forgetfulness and poor concentration (42%), and fatigue (45%). According to the GOS good recovery (82%) or moderate disability (18%) was seen. Application of the DOS showed more cognitive (40%) and behavioural problems (48%), interfering with return to work. Correlation between the GOS and DOS was high (r=0.87, p<0.01). Outcome correlated with duration of PTA (r=-0.46) but not significantly with GCS on admission (r=0.19). In multiple regression analysis, PTA and the number of complaints 3 months after injury explained 49% of variance on outcome as assessed with the GOS, and 60% with the DOS.
CONCLUSIONS: In mild to moderate head injury outcome is determined by duration of PTA and not by GCS on admission. Most patients return to work despite having complaints. The application of a more detailed outcome scale will increase accuracy in predicting outcome in this category of patients with head injury.