title: The measurement of postoperative pain: a comparison of intensity scales in younger and older surgical patients.
abstract: The psychometric properties of pain intensity scales for the assessment of postoperative pain across the adult lifespan have not been reported. The objective of this study was to compare the feasibility and validity of the Numeric Rating Scale (NRS), Verbal Descriptor Scale (VDS), and Visual Analog Scale (horizontal (VAS-H) and vertical (VAS-V) line orientation) for the assessment of pain intensity in younger and older surgical patients. At 24h following surgery, 504 patients, who were receiving i.v. morphine via patient-controlled analgesia, completed the pain intensity measures and the McGill Pain Questionnaire (MPQ) in a randomized order. They were asked which scale was easiest to complete, the most accurate measure, and which they would most prefer to complete in the future, as an index of face validity. The amount of opioid self-administered was recorded. Age differences in postoperative pain intensity were not found. However, elderly patients obtained lower MPQ scores and self-administered less morphine than younger people. Psychometric analyses suggested that the NRS was the preferred pain intensity scale. It had low error rates, and higher face, convergent, divergent and criterion validity than the other scales. Most importantly, its properties were not age-related. The VDS also had a favourable profile with low error rates and good face, convergent and criterion validity. Finally, difficulties with VAS use among the elderly were identified, including high rates of unscorable data and low face validity. Its use with elderly postoperative patients should be discouraged.
authors.affiliation: School of Kinesiology and Health Science, York University, Toronto, Ont., Canada Department of Psychology, York University, Toronto, Ont., Canada Department of Anaesthesia and Pain Management, University Health Network, Toronto General Hospital, Toronto, Canada Department of Anaesthesia, University of Toronto, Toronto, Ont., Canada Department of Psychiatry, University of Toronto, Toronto, Ont., Canada.
authors.forename: Lucia
authors.initials: L
authors.lastname: Gagliese
authors.forename: Nataly
authors.initials: N
authors.lastname: Weizblit
authors.forename: Wendy
authors.initials: W
authors.lastname: Ellis
authors.forename: Vincent W S
authors.initials: VWS
authors.lastname: Chan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D003710:Demography; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods*; D010149:Postoperative Pain / Q000175:diagnosis* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity