English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  Many people suffer with Osteoarthritis (OA) and subsequent morbidity. Therefore, measuring outcome associated with OA is important. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) has been a widely used patient reported outcome in OA. However, there is relatively little evidence to support the use of the Visual Analogue Scale (VAS) version of the scale. We aimed to explore the internal validity and responsiveness of this VAS version of the WOMAC.    Methods  Patients with chronic hip or knee pain of mechanical origin, waiting for a hip or knee joint replacement completed the WOMAC as part of a study to investigate the effects of acupuncture and placebo controls. Validity was tested using factor analysis and Rasch analysis, and responsiveness using standardised response means.    Results  Two hundred and twenty one patients (mean age 66.8, SD 8.29, 58% female) were recruited. Factor and Rasch analysis confirmed unidimensional Pain and Physical Functioning scales, capable of transformation to interval scaling and invariant over time. Some Differential Item Functioning (DIF) was observed, but this cancelled out at the test level. The Stiffness scale fitted the Rasch model but adjustments for DIF could not be made due to the shortness of the scale. Using the interval transformed data, Standardised Response Means were smaller than when using the raw, ordinal data.    Conclusions  The WOMAC Pain and Physical Functioning subscales satisfied unidimensionality and ordinal scaling tests, and the ability to transform to an interval scale. Some Differential Item Functioning was observed, but this cancelled out at the test level and, by doing so, at the same time removed the disturbance of unidimensionality. The scaling characteristics of sets of items which use VAS require further analysis, as it would appear that they can lead to spurious levels of responsiveness and scale compression because they exaggerate the distortion of the ordinal scale.    Trial number  UKCRN study ID: 4881  ISRCTN78434638

The Visual Analogue WOMAC 3.0 scale - internal validity and responsiveness of the VAS version