title: Discrepancies in describing pain: is there agreement between numeric rating scale scores and pain reduction percentage reported by patients with musculoskeletal pain after corticosteroid injection?
abstract: OBJECTIVE
  Pain intensity is commonly rated on an 11-point Numerical Pain Rating Scale which can be expressed as a calculated percentage pain reduction (CPPR), or by patient-reported percentage pain reduction (PRPPR). We aimed to determine the agreement between CPPR and PRPPR in quantifying musculoskeletal pain improvement at short-term follow-up after a corticosteroid injection.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Urban, academic, physical medicine, and rehabilitation outpatient interventional musculoskeletal and spine center.
  
  
  METHODS
  The agreement between CPPR and PRPPR was determined by concordance correlation coefficient (CCC) in subjects who had experienced improvement in musculoskeletal or radicular pain 3 weeks after a first-time injection at our clinic. Subjects who experienced unchanged pain (PRPPR = 0) were compared to CPPR with paired t-test.
  
  
  RESULTS
  We examined 197 subjects with greater than 3/10 pain who underwent first-time fluoroscopic-guided corticosteroid injections. Ninety-three subjects reported higher PRPPR than CPPR values, and 41 subjects reported higher CPPR values. The CCC between CPPR and PRPPR was 0.44 (95% CI 0.35-0.54), with a precision of 0.54 and an accuracy of 0.81, and 95% limits of agreement ranging between -41% and +73%. Values for CCC, precision, and accuracy were higher for males compared to females and were highest in the youngest age group (18-40) and lowest in the middle age group (41-60).
  
  
  CONCLUSIONS
  PRPPR may not agree with CPPR at 3 week follow-up, as these individuals tend to report a higher estimated percentage improvement compared to the value calculated from their pain scores.
authors.affiliation: The Rehabilitation Institute of Chicago/Northwestern McGaw Medical Center, Department of Physical Medicine and Rehabilitation, Chicago, Illinois.
authors.forename: Daniel
authors.initials: D
authors.lastname: Cushman
authors.affiliation: The Rehabilitation Institute of Chicago/Northwestern McGaw Medical Center, Department of Physical Medicine and Rehabilitation, Chicago, Illinois.
authors.forename: Zachary
authors.initials: Z
authors.lastname: McCormick
authors.affiliation: The Rehabilitation Institute of Chicago/Northwestern McGaw Medical Center, Department of Physical Medicine and Rehabilitation, Chicago, Illinois.
authors.forename: Ellen
authors.initials: E
authors.lastname: Casey
authors.affiliation: Hospital of the University of Pennsylvania, Department of Physical Medicine and Rehabilitation, Philadelphia, Pennsylvania, USA.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Plastaras
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015552:Injections, Intralesional; D008297:Male; D008875:Middle Aged; D059352:Musculoskeletal Pain / Q000188:drug therapy*; D010147:Pain Measurement / Q000379:methods*; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones
keywords: Acute Pain; Chronic Pain; Memory; Musculoskeletal Pain; Pain Measurement; Radiculopathy