title: Can functional capacity tests predict future work capacity in patients with whiplash-associated disorders?
abstract: OBJECTIVE
  To determine whether functional capacity evaluation (FCE) tests predict future work capacity (WC) of patients with whiplash-associated disorders (WADs) grades I and II who did not regain full WC 6 to 12 weeks after injury.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Rehabilitation center.
  
  
  METHODS
  Workers (N=267) listed on workers' compensation with grade I or II WADs 6 to 12 weeks after injury.
  
  
  METHODS
  Patients performed 8 work-related FCE tests.
  
  
  METHODS
  WC (0-100%) measured at baseline and 1, 3, 6, and 12 months after testing. Correlation coefficients between FCE tests and WC were calculated. A linear mixed-model analysis was used to assess the association between FCE and future WC.
  
  
  RESULTS
  Mean ± SD WC increased over time from 20.8%±27.6% at baseline to 32.3%±38.4%, 51.3%±42.8%, 65.6%±42.2%, and 83.2%±35.0% at the 1-, 3-, 6-, and 12-month follow-ups, respectively. Correlation coefficients between FCE tests and WC ranged from r=.06 (lifting low at 12-mo follow-up) to r=.39 (walking speed at 3mo). Strength of the correlations decreased over time. FCE tests did not predict WC at follow-up. The predictors of WC were ln (time) (β=23.74), mother language (β=5.49), WC at baseline (β=1.01), and self-reported disability (β=-.20). Two interaction terms, ln (time) × WC (β=-.19) and ln (time) × self-reported disability (β=-.21), were significant predictors of WC.
  
  
  CONCLUSIONS
  FCE tests performed within 6 to 12 weeks after WADs injury grades I and II are associated with WC at baseline but do not predict future WC, whereas time course, mother language, WC at baseline, and self-reported disability do predict future WC. Additionally, the interaction between time course WC at baseline and self-reported disability predicted future WC.
authors.affiliation: Department of Work Rehabilitation, Rehaklinik Bellikon, Suva Care, Bellikon, Switzerland; Department of Rehabilitation Medicine, Center for Rehabilitation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. Electronic address: maurizio.trippolini@rehabellikon.ch.
authors.forename: Maurizio A
authors.initials: MA
authors.lastname: Trippolini
authors.affiliation: Department of Rehabilitation Medicine, Center for Rehabilitation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Pieter U
authors.initials: PU
authors.lastname: Dijkstra
authors.affiliation: Division of Epidemiology, Della Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; University of Ontario, Institute of Technology, Faculty of Health Sciences, Oshawa, Ontario, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Côté
authors.affiliation: Central Office for Statistics in Accident Insurance, Lucerne, Switzerland.
authors.forename: Stefan M
authors.initials: SM
authors.lastname: Scholz-Odermatt
authors.affiliation: Department of Rehabilitation Medicine, Center for Rehabilitation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Jan H
authors.initials: JH
authors.lastname: Geertzen
authors.affiliation: Department of Rehabilitation Medicine, Center for Rehabilitation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Michiel F
authors.initials: MF
authors.lastname: Reneman
mesh_terms: D000328:Adult; D059026:Diagnostic Self Evaluation; D005260:Female; D006801:Humans; D007802:Language; D017770:Lifting; D008297:Male; D019547:Neck Pain / Q000209:etiology; D010147:Pain Measurement; D011446:Prospective Studies; D013997:Time Factors; D016138:Walking / Q000502:physiology; D014911:Whiplash Injuries / Q000150:complications / Q000503:physiopathology*; D014938:Work Capacity Evaluation
keywords: Disability evaluation; Neck pain; Prognosis; Rehabilitation; Return to work; Whiplash injuries