Long-term disability in the local population 2 years after mild head injury: Prospective cohort study

Introduction:  More than 4000 patients with mild head injury are managed in public hospitals in Hong Kong every year. It is a common belief that mild head injuries do not result in long-term disabilities. We aim to: (i) investigate the disability after mild head injury using objective assessment tools; and (ii) analyse risk factors that contribute to these disability.

Methods:  Patients with a Glasgow Coma Score of 13–15 admitted between January and March 2002 were recruited for study. Their long-term clinical outcome (2 years after initial injury) was prospectively documented with the Glasgow outcome scale – extended (GOSE). Glasgow outcome scale – extended is the primary outcome measure. A GOSE score less than 7 was considered failure to restore to previous working capacity.

Results:  One hundred and sixty-two patients were recruited, of which 101 were successfully contacted. Two years after injury, 28.7% of the patients scored less than 7 (failure to restore working capacity). Injury on duty was shown to be a significant risk factor for predicting long-term disability (P = 0.03). Radiological abnormality was not a significant predictor in long-term disabilities.

Conclusion:  Incidence of long-term disability after mild head injury is common among the local working population in Hong Kong and should not be overlooked. Further research is needed to quantify the disability and to identify possible risk factors.