title: Sitting and standing tolerance in patients with chronic back pain: comparison between physician prediction and covert observation.
abstract: OBJECTIVE
  To measure covertly observed continuous sitting and standing tolerance in patients with chronic back pain and to compare observations to physician predictions.
  
  
  METHODS
  Blinded, prospective, cohort study.
  
  
  METHODS
  Ambulatory referral centers, both public and private, at 5 major medical centers in the eastern United States.
  
  
  METHODS
  All volunteers (N=154; 64.0% women, mean age, 48.7y; 16.8% had active lawsuits) with diagnosis codes of the International Classification of Diseases, 9th Revision consistent with thoracic and/or lumbosacral back pain were selected from a cohort of 651 outpatients with chronic pain enrolled in the Multiperspective Multidimensional Pain Assessment Protocol (MMPAP).
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Continuous sitting and standing tolerance was measured by (1). covert observation of subjects during the MMPAP trial and (2). blinded expert physician prediction based on complete history and physical examination.
  
  
  RESULTS
  Most (124/154, 80.5%) subjects stood for 30 minutes or more and most (124/154, 80.5%) sat for 60 minutes or more. Overall, physicians underpredicted the ability to sit 60 minutes or more and to stand 30 minutes or more. Physician prediction showed poor correlation to covert observation for sitting tolerance (kappa=-.061, P=.221) and standing tolerance (kappa=-.021, P=.727).
  
  
  CONCLUSIONS
  The majority of this sample demonstrated the ability to sit continuously 60 minutes or more and to stand continuously 30 minutes or more while being covertly observed. Expert physician prediction showed poor correlation to covertly observed sitting and standing tolerances, raising doubt about the validity of using physician evaluation to establish work restrictions in patients with chronic back pain. These findings are preliminary, follow only a brief period of covert observation, and indicate the need for further research in this area.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Virginia Commonwealth University/Medical College of Virginia, Richmond, VA 23298, USA.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Brokaw
authors.forename: William C
authors.initials: WC
authors.lastname: Walker
authors.forename: David X
authors.initials: DX
authors.lastname: Cifu
authors.forename: Marie
authors.initials: M
authors.lastname: Gardner
mesh_terms: D001416:Back Pain / Q000503:physiopathology*; D002908:Chronic Disease; D015331:Cohort Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008487:Medical History Taking; D008875:Middle Aged; D010808:Physical Examination; D010820:Physicians / Q000592:standards*; D011187:Posture / Q000502:physiology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D014481:United States