Comment on “Shoulder Pain and Disability Index: Italian cross-cultural validation in patients with non-specific shoulder pain”

Abstract

Dear Editor, We read with interest the paper by Brindisino et al., performing the Italian cross-cultural validation of the Shoulder Pain and Disability Index (SPADI) in individuals with non-specific shoulder pain. While we recognize the uttermost importance of using psychometrically sound Patient-Reported Outcome Measures (PROMs) in research and clinical settings, we are concerned about some methodological aspects which may lead to an overestimation of study findings. It is our opinion that the instrument has not been appropriately validated. According to the more recent guidelines for psychometric assessment of PROMs (i.e., COnsensus-based Standards for the selection of health Measurement INstruments [COSMIN]), three measurement domains should be investigated, i.e., reliability, validity, and responsiveness. The domain reliability refers to three measurement properties: internal consistency, reliability (i.e., test-retest, inter/intra-rater), and measurement error. Validity includes content validity, construct validity (i.e., including structural validity, hypotheses testing, and cross-cultural validity), and criterion validity.