title: A comparison of three self-report pain scales in adults with acute pain.
abstract: BACKGROUND
  Several pain rating methods are used to quantify pain. Although these instruments have been extensively studied, their inter-agreement, especially in emergency department (ED) settings, has yet to be determined.
  
  
  OBJECTIVE
  This study was designed to assess the agreement between Visual Analog Scale (VAS), Color Analog Scale (CAS), and verbally administered Numeric Rating Scale (NRS) in the emergency setting.
  
  
  METHODS
  A sample of 150 adult patients presenting with acute pain to two EDs was recruited. Patients' pain severity at presentation, 30 and 60 min later was assessed using the three pain scales. The agreement between pain scales was assessed using Bland-Altman method and Spearman correlation. We described a composite measure to serve as the gold standard and to be compared with each score. Factor analysis was also performed to assess the underlying construct.
  
  
  RESULTS
  Spearman correlation coefficients between NRS and CAS, NRS and VAS, and CAS and VAS were 0.95, 0.94, and 0.94, respectively (p < 0.001). On a scale of 0 to 10, the 95% limits of agreement between the paired NRS and VAS, VAS and CAS, and CAS and NRS as measured by Bland-Altman method ranged from -2.0 to 2.6, from -2.7 to 2.0, and from -2.1 to 2.0, respectively. The Kaiser-Meyer-Oklin measure of sampling adequacy was 0.785 and Bartlett's test for sphericity was significant (p < 0.001).
  
  
  CONCLUSIONS
  The three pain scales were strongly correlated at all time periods. The findings suggest that NRS, CAS, and VAS can be interchangeably applied for acute pain measurement in adult patients.
authors.affiliation: Emergency Medicine Department, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Bahreini
authors.affiliation: Emergency Medicine Department, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Jalili
authors.affiliation: Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Maziar
authors.initials: M
authors.lastname: Moradi-Lakeh
mesh_terms: D059787:Acute Pain / Q000175:diagnosis*; D000293:Adolescent; D000328:Adult; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods*; D057240:Patient Preference; D057566:Self Report; D018709:Statistics, Nonparametric; D055815:Young Adult
keywords: Color Analog Scale; Numeric Rating Scale; Visual Analog Scale; acute pain; emergency department; pain assessment