Validity and Reliability of 11-face Faces Pain Scale in the Iranian Elderly Community with Chronic Pain

BACKGROUND: Accurate pain assessment in elderly population is essential for pain management and nurses have a pivotal role. The 11-face Faces Pain Scale (FPS-11) is a well-established pain assessment measure that has not been validated in the Iranian elderly. AIM: The aim was to study the property assessment of the Iranian version of FPS-11 (FPS-11-IR) among elderly outpatients with chronic pain. METHODS: This is a cross-sectional validation study that conducted in three outpatient clinics in Tehran, Iran, in 2017. Older people aged ≥60 years (n = 217) with chronic knee pain due to degenerative joint disease were participated. The construct validity was examined by applying contrast constructs, and the face validity was determined by rank-ordering test. To assess concurrent validity, the Spearman's correlation coefficient was calculated between the scores of 11-point Numeric Rating Scale (NRS) and FPS-11-IR. Test–retest reliability was determined in 1-week interval. RESULTS: Most of elderly participants (72%) agreed that pain construct displays in faces of the FPS-11-IR and participants” agreement on face rank ordering were vary for each face, ranging from 80% to 100%. Spearman's correlation coefficient between FPS-11-IR and NRS scores was very strong (r = 0.91, P < 0.01). Intraclass correlation coefficient between test–retest scores was 0.96 that indicates excellent reliability. CONCLUSIONS: The FPS-11-IR is a reliable and valid pain assessment scale to use in geriatric patients chronic pain.