Psychometric properties of pain intensity scales comparing among postoperative adult patients, elderly patients without and with mild cognitive impairment in China

BackgroundWestern studies have shown that patients with mild or moderate cognitive impairment (CI) can use pain intensity scales to report pain reliably and validly, however, the qualities of pain intensity scales use in various age groups including elderly with CI are varied. In China, there is a lack of studies.ObjectiveTo compare psychometric properties of five evidence-supported pain intensity scales including the Verbal Descriptor Scale (VDS), the Numeric Rating Scale (NRS), the Faces Pain Scale (FPS), the Numeric Box-21 Scale (BS-21), and the Colored Analogue Scale (CAS) in postoperative adults varying in ages including elderly with mild CI.DesignDescriptive comparative study.SettingA university-affiliated hospital in China.ParticipantsTwo hundred surgical patients were recruited purposively with 50 for each group: young adults, middle-aged adults, elderly without CI, and elderly with mild CI.MethodsParticipants rated the vividly remembered, current, worst, least, and average pain, and indicated scale preference and simplicity. Scale face validity, concurrent validity, convergent validity, and test–retest reliability were assessed. Fisher's exact tests were used to investigate whether face validity was related to different age groups and levels of CI. One-way ANOVA and Kruskal–Wallis test were used to test the differences of concurrent validity, convergent validity, and test–retest reliability coefficients of each pain scale among the four groups.ResultsRegarding face validity, the FPS was ranked best as nearly half of the patients selected it as both the most preferred and simplest scale and it had low errors; the VDS and the NRS were ranked following the FPS; however, the BS-21 and the CAS were ranked last. The concurrent validity, convergent validity, and test–retest reliability of all five pain scales were supported in use with the four groups. The differences in psychometric properties among the four groups were only found in face validity and test–retest reliability.ConclusionThe findings support the psychometric properties of all five pain scales for pain assessment in Chinese adults including elderly with mild CI. However, the FPS appears to be the best, followed by the VDS and the NRS.