title: Evaluation of 21-numbered circle and 10-centimeter horizontal line visual analog scales for physician and parent subjective ratings in juvenile idiopathic arthritis.
abstract: OBJECTIVE
  To evaluate the measurement properties of 21-numbered circle visual analog scales (VAS) and traditional 10-cm horizontal line VAS for physician and parent subjective ratings in children with juvenile idiopathic arthritis (JIA).
  
  
  METHODS
  We studied 2 patient samples in whom physician global rating of overall disease activity, parent global rating of the child's overall well-being, and parent rating of intensity of child's pain were performed using traditional 10-cm horizontal line VAS (n = 397) or 21-numbered circle VAS (n = 471). The measurement performances of the 2 VAS formats were examined by assessing construct validity, score distribution, responsiveness to change over time, and minimal clinically important difference (MCID).
  
  
  RESULTS
  Most Spearman correlations with other JIA outcome measures yielded by 21-numbered circle VAS were greater than those obtained with 10-cm horizontal line VAS, revealing that the circle VAS format has better construct validity. Ceiling effects (i.e., score = 0) for physician and parent global ratings were 43.7% and 32.9%, respectively, on 21-numbered circle VAS, and 31.6% and 35.3%, respectively, on 10-cm horizontal line VAS. Responsiveness of 21-numbered circle VAS was good (standardized response mean > 0.8) or moderate (standardized response mean > 0.6) among patients classified as improved or worsened, respectively, by the physician or the parent. Overall, MCID values for 21-numbered circle VAS tended to be greater for worsening than for improvement.
  
  
  CONCLUSIONS
  The 21-numbered circle VAS are a suitable alternative to the 10-cm horizontal line VAS and may facilitate incorporation of physician and parent subjective ratings in standard clinical practice.
authors.affiliation: Istituto di Ricovero e Cura a Carattere Scientifico G. Gaslini, Genova, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Filocamo
authors.forename: Sergio
authors.initials: S
authors.lastname: Davì
authors.forename: Angela
authors.initials: A
authors.lastname: Pistorio
authors.forename: Marta
authors.initials: M
authors.lastname: Bertamino
authors.forename: Nicolino
authors.initials: N
authors.lastname: Ruperto
authors.forename: Bianca
authors.initials: B
authors.lastname: Lattanzi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Consolaro
authors.forename: Silvia
authors.initials: S
authors.lastname: Magni-Manzoni
authors.forename: Roberta
authors.initials: R
authors.lastname: Galasso
authors.forename: Giulia Camilla
authors.initials: GC
authors.lastname: Varnier
authors.forename: Alberto
authors.initials: A
authors.lastname: Martini
authors.forename: Angelo
authors.initials: A
authors.lastname: Ravelli
mesh_terms: D001171:Arthritis, Juvenile / Q000503:physiopathology*; D006801:Humans; D010146:Pain / Q000503:physiopathology; D010147:Pain Measurement; D010290:Parents / Q000523:psychology*; D010361:Patients; D010820:Physicians / Q000523:psychology*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires