title: Syncope and Motor Vehicle Crash Risk: A Danish Nationwide Study.
abstract: OBJECTIVE
  Syncope may have serious consequences for traffic safety. Current clinical guideline recommendations on driving following syncope are primarily based on expert consensus.
  
  
  OBJECTIVE
  To identify whether there is excess risk of motor vehicle crashes among patients with syncope compared with the general population.
  
  
  METHODS
  Danish nationwide cohort study from January 1, 2008, to December 31, 2012. Through individual-level linkage of nationwide administrative registers, all Danish residents 18 years or older were identified. Of 4 265 301 eligible Danish residents, we identified 41 039 individuals with a first-time diagnosis of syncope from emergency department or hospital.
  
  
  METHODS
  Rate of motor vehicle crashes (including nonfatal and fatal crashes), based on multivariate Poisson regression models, using the total Danish population as reference.
  
  
  RESULTS
  The 41 039 patients with syncope had a median age of 66 years (interquartile range [IQR], 47-78 years); 51.0% were women; and 34.8% had cardiovascular disease. Through a median follow-up of 2.0 years (IQR, 0.8-3.3 years), 1791 patients with syncope (4.4%) had a motor vehicle crash, 78.1% of which led to injury (n = 1398) and 0.3% to death (n = 6). The crude incidence rate of motor vehicle crashes was almost doubled among patients with syncope (20.6 per 1000 person-years; 95% CI, 19.7-21.6) compared with the general population (12.1; 95% CI, 12.0-12.1), with a rate ratio (RR) of 1.83 (95% CI, 1.74-1.91) after adjustment for age, sex, socioeconomic position, and relevant comorbidities and pharmacotherapy. Men had a relatively higher rate of motor vehicle crashes (RR, 1.91; 95% CI, 1.79-2.03) than women (RR, 1.74; 95% CI, 1.63-1.87). The excess risk of motor vehicle crashes persisted throughout the follow-up period. The 5-year crash risk following syncope was 8.2% (95% CI, 7.5%-8.8%) among the population aged 18 to 69 years compared with 5.1% (95% CI, 4.7%-5.4%) in the general population.
  
  
  CONCLUSIONS
  Prior hospitalization for syncope was associated with increased risk of motor vehicle crashes throughout the follow-up period. This study suggests that syncope should be considered as one of several factors in a broad assessment of fitness to drive.
authors.affiliation: Department of Cardiology, Copenhagen University Gentofte Hospital, Hellerup, Denmark.
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Numé
authors.affiliation: Department of Cardiology, Copenhagen University Gentofte Hospital, Hellerup, Denmark2The National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark3The Danish Heart Foundation, Copenhagen, Denmark.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Gislason
authors.affiliation: Department of Cardiology, Copenhagen University Gentofte Hospital, Hellerup, Denmark4The Research House, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Christine B
authors.initials: CB
authors.lastname: Christiansen
authors.affiliation: Department of Cardiology, Copenhagen University Gentofte Hospital, Hellerup, Denmark.
authors.forename: Deewa
authors.initials: D
authors.lastname: Zahir
authors.affiliation: Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California6Department of Medicine, Stanford University School of Medicine, Stanford, California.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hlatky
authors.affiliation: Institute of Health, Science and Technology, Aalborg University, Aalborg, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Torp-Pedersen
authors.affiliation: Department of Cardiology, Copenhagen University Gentofte Hospital, Hellerup, Denmark.
authors.forename: Martin H
authors.initials: MH
authors.lastname: Ruwald
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D016247:Information Storage and Retrieval; D008297:Male; D008875:Middle Aged; D012042:Registries; D012306:Risk; D013575:Syncope / Q000453:epidemiology*; D055815:Young Adult