title: Long-term follow-up of trauma patients before and after implementation of a physician-staffed helicopter: A prospective observational study.
abstract: BACKGROUND
  The first Danish Helicopter Emergency Medical Service (HEMS) was introduced May 1st 2010. The implementation was associated with lower 30-day mortality in severely injured patients. The aim of this study was to assess the long-term effects of HEMS on labour market affiliation and mortality of trauma patients.
  
  
  METHODS
  Prospective, observational study with a maximum follow-up time of 4.5 years. Trauma patients from a 5-month period prior to the implementation of HEMS (pre-HEMS) were compared with patients from the first 12 months after implementation (post-HEMS). All analyses were adjusted for sex, age and Injury Severity Score.
  
  
  RESULTS
  Of the total 1994 patients, 1790 were eligible for mortality analyses and 1172 (n=297 pre-HEMS and n=875 post-HEMS) for labour market analyses. Incidence rates of involuntary early retirement or death were 2.40 per 100 person-years pre-HEMS and 2.00 post-HEMS; corresponding to a hazard ratio (HR) of 0.72 (95% confidence interval (CI) 0.44-1.17; p=0.18). The HR of involuntary early retirement was 0.79 (95% CI 0.44-1.43; p=0.43). The prevalence of reduced work ability after three years were 21.4% vs. 17.7%, odds ratio (OR)=0.78 (CI 0.53-1.14; p=0.20). The proportions of patients on social transfer payments at least half the time during the three-year period were 30.5% vs. 23.4%, OR=0.68 (CI 0.49-0.96; p=0.03). HR for mortality was 0.92 (CI 0.62-1.35; p=0.66).
  
  
  CONCLUSIONS
  The implementation of HEMS was associated with a significant reduction in time on social transfer payments. No significant differences were found in involuntary early retirement rate, long-term mortality, or work ability.
authors.affiliation: Department of Anaesthesia, Centre of Head and Orthopaedics 4231, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark. Electronic address: milafun@hotmail.com.
authors.forename: Kamilia S
authors.initials: KS
authors.lastname: Funder
authors.affiliation: Department of Anaesthesia, Centre of Head and Orthopaedics 4231, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Lars S
authors.initials: LS
authors.lastname: Rasmussen
authors.affiliation: Department of Anaesthesiology and Intensive Care, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.
authors.forename: Nicolai
authors.initials: N
authors.lastname: Lohse
authors.affiliation: The Research Unit for General Practice and Section of General Practice, Department of Public Health, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Volkert
authors.initials: V
authors.lastname: Siersma
authors.affiliation: Department of Anaesthesia, Centre of Head and Orthopaedics 4231, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Rasmus
authors.initials: R
authors.lastname: Hesselfeldt
authors.affiliation: Department of Anaesthesia, Centre of Head and Orthopaedics 4231, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Steinmetz
mesh_terms: D017732:Air Ambulances / Q000458:organization & administration; D000401:Aircraft; D003718:Denmark / Q000453:epidemiology; D004632:Emergency Medical Services / Q000458:organization & administration; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D017063:Outcome Assessment, Health Care; D010820:Physicians; D016016:Proportional Hazards Models; D011446:Prospective Studies; D013997:Time Factors; D000078329:Workforce; D014947:Wounds and Injuries / Q000401:mortality / Q000628:therapy*
keywords: Health economics; Helicopter emergency medical system; Return to work; Trauma care