Background: Trauma is the number one killer of children and young adults and the  most common cause for hospital admissions for these age-groups in Sweden. Trauma is  also one of the most common causes for hospital care and early death for older people.  In the last decades trauma care has advanced and improved short-term survival of  injured but knowledge of the long-term outcome is limited.

The overall aim of this thesis is to investigate long-term outcome and health-related  quality of life after injuries in different age groups and to identify factors associated  with outcome.

Methods: The thesis is based on four studies. In the first study patients with major  trauma were contacted 5 years after injury and HRQL was measures using the SF-36  questionnaire and compared to an age and sex-matched reference group. In the second  study data was collected on children with injuries to describe demographic and injury  characteristics and outcome. The sample in the second study was the source for the  third and fourth study. The third study measured HRQL using the PedsQL 4.0 in a  cohort of children 6 years after injury and determined the relationship within subgroups  in the cohort. The fourth study measured child HRQL in a sample of children after  injury and their parent´s and determined the relationship within scoring results and the impact of parents reported mental health status.

Results: The adult major trauma patients (n=205) reported significantly lower HRQL  scores in all eight domains compared to the reference group. A large number of patients  suffered from physical (68%) and psychological disabilities (41%) and nearly half reported the need for better follow-up after discharge from hospital. The severity of the injury did not anticipate a lower health-related quality of life. In the pediatric group  (n=432) the median injury severity score was 4 (IQR 1-9), 50% sustained head injuries  and the most severe head injuries were seen in the youngest age group. Mortality rate  was low (1%), 19% stayed in a PICU and the median length of hospital stay was two  days. In the follow-up study (n=204) the youngest children had the lowest PedsQL  scores. Children who suffered from extremity injuries had lower scores in the school  functioning compared to children with head injuries. The levels of agreement between  child self-report and parent proxy report of PedsQL 4.0 scales were excellent  (ICC≥0.80) for all scales with the exception of children´s self-reported emotional  functioning. Multiple regression analyses showed that poor parental mental health  status contributed to worse child self-report and parent proxy report of children´s  HRQL.

Conclusion: Adult major trauma patients have significant disabilities 5 years after  injury. Improved follow-up by trauma specialist teams are needed. Children´s HRQL 6  years after trauma seems to in parity or better than healthy peers. Parent´s mental health  status can possibly impact on children´s HRQL long after an injury. Further studies are  recommended to evaluate the PedsQL 4.0versions for self-report in pediatric trauma  population.