E092 Confirmatory factor analyses of the Tampa Scale of Kinesiophobia 11-item version and Pain Catastrophising Scale: A cross-sectional study in people living with axial spondyloarthritis
Authors: Rouse Peter C , Ingram Thomas A , Standage Martyn , Sengupta Raj 
Published: April 2023

Abstract

Background/Aims
The Fear Avoidance Model (FAM) proposes pain-related fear of movement and pain catastrophising to be prominent psychological experiences that compromise physical function and activity behaviour in people living with chronic pain. Yet, little research has tested the FAM in people living with axial spondyloarthritis (axSpA) despite the evidenced benefits of physical activity and exercise. This study examines the structural aspect of construct validity of the 11-item Tampa Scale of Kinesiophobia (TSK-11) and Pain Catastrophising Sale (PCS) as an important first step, to establish valid measurement tools to effectively test the relevance of the FAM for people with axSpA.

Methods
An online survey was distributed via the National Axial Spondyloarthritis Society including the TSK-11 and PCS. Ninety-eight people with axSpA (M Age = 45.62 SD =  12.16, M BASFI = 3.7 SD = 2.60, Female = 70%, NSAID use = 58.76%, bDMARDS use = 62.24%) completed the survey (December 2020- April 2021). Internal consistency was examined via Cronbach alpha values and confirmatory factor analysis tested the TSK-11's two-factor structure and PCS's three-factor structure. A model has excellent fit to the data with values &lt; 3 for the CMIN/DF, and around .95 for CFI, .06 for RMSEA, .08 for SRMR. Factor loadings &lt; .40 support deletion.

Results
Alpha values supported the internal consistency of participant responses to the somatic (.78), avoidance behaviour (.80) and overall fear of movement (.89) TSK-11 items. Fit indices also showed a good fit to the data for the TSK-11’s two-factor structure once two error terms were correlated (CMIN/DF = 1.77/42, CFI = .93, RMSEA = .09 (.05 - .12), SRMR= .06). Standardised factors loadings for the somatic and avoidance factors ranged from .43 - .80 and .60 - .72, respectively. Internal consistency for the responses to the PCS-Helplessness (.92), PCS-Magnification (.82), PCS-Rumination (.94) and overall pain catastrophising (.95) scales were also supported. A good fit to the data was shown for the three-factor structure of the PCS (CMIN/DF = 2.15/61, CFI = .94, RMSEA= .11 (.08-.14), SRMR = .04) when two errors were correlated. Standardised factors loadings ranged from .67-.90, (Helplessness), .89 - .92 (Rumination) and .73 - .85 (Magnification).

Conclusion
The TSK-11 and PCS can be used to measure axSpA patient’s pain related fear of movement and pain catastrophising, but data support continued examination of their construct validity in larger samples of axSpA patients. One TSK-11 item revealed a border line factor loading (.43) for the somatic factor (“pain lets me know when to stop exercising so that I don’t injure myself”). Psychometrically valid instruments will help examine the role of pain related fear of movement and pain catastrophising on important health related outcomes for axSpA patients including physical function and physical activity behaviour.
Disclosure
P.C. Rouse: Grants/research support; PhD studentship matched funded by Bath Institute for Rheumatic Diseases (RAG-PR-33-120318). T.A. Ingram: None. M. Standage: None. R. Sengupta: Honoraria; Received honoraria for giving talks from Abbyie, Biogen, UCB, Novartis and Pfizer. Grants/research support; Research grants have been received from UCB, Abbvie, and Novartis.