A comparison of four self-report scales of pain intensity in 6- to 8-year-old children.

There are many different instruments for assessing pain intensity in children, but the agreement between them is unclear. The aims of this study were to determine the 1-dimensionality of 4 widely used self-report scales for measuring the intensity of pediatric pain, and the agreement between them. A sample of 126 school children between 6 and 8 years of age (mean = 6.87 years; SD = 0.68 year) were interviewed individually and asked to identify the most frequent pain that they had experienced in the 3 months before the interview, and to report their maximum pain intensity using all 4 scales (Visual Analogue Scale, Coloured Analogue Scale, Faces Pain Scale-Revised and Numerical Rating Scale-11). A factor analysis was conducted to determine the 1-dimensionality of these 4 scales. Agreement was calculated with the Bland-Altman method with a maximum limit of agreement set at ± 20 mm. Our data show the 1-dimensionality of the scales. The 95% limits of agreement between each pair of measures were as follows: VAS/CAS (-23.8, 23.4); VAS/NRS-11 (-41, 31.1); VAS/FPS-R (-38.3, 33.6); CAS/NRS-11 (-35.6, 26.2); CAS/FPS-R (-36.4, 32.1), and FPS-R/NRS-11 (-36.3, 31). Our data suggest that these 4 instruments measure 1 common factor but that they are not concordant.