Confirmatory Factor Analysis and Assessment of Differential Item Functioning of the Satisfaction with Appearance Scale in Systemic Sclerosis: A Comparison Across Sex, Race/Ethnicity and Disease Subtype

Lisa Jewett¹, Linda Kwakkenbos², Vanessa L. Malcarne³, Marie-Eve Carrier² and Brett D. Thombs⁴, ¹Department of Psychiatry, McGill University, Montreal, QC, Canada, ²McGill University, Montreal, QC, Canada, ³SDSU/UC San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, ⁴Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada

Meeting: 2016 ACR/ARHP Annual Meeting

Date of first publication: September 28, 2016

Keywords: Body image, measure, psychosocial, scleroderma and systemic sclerosis

Session Information

Date: Monday, November 14, 2016

Title: Systemic Sclerosis, Fibrosing Syndromes, and Raynaud's – Clinical Aspects and Therapeutics - Poster II

Session Type: ACR Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose: The Satisfaction with Appearance Scale (SWAP) has been used to assess dissatisfaction with appearance and social discomfort relative to disfigurement in systemic sclerosis (scleroderma, SSc); however, it has not been validated across sexes, different racial/ethnic groups, and varying disease subtypes. The study objectives were to evaluate the established two-factor structure of the SWAP; and examine the metric equivalences of the SWAP among male and female patients, Black and White patients, and patients with diffuse and limited SSc subtypes.

Methods: SSc patients were sampled from 21 centers within the international Scleroderma Patient-centered Intervention Network (SPIN) Cohort. Confirmatory factor analysis (CFA) was used to evaluate the established SWAP two-factor structure (Dissatisfaction with Appearance and Social Discomfort). The Multiple-Indicator Multiple-Cause (MIMIC) model was utilized to assess differential item functioning (DIF).

Results: The SWAP was completed by 748 SSc patients, including 651 female patients, 700 White patients, and 455 with limited SSc. Results from the CFA revealed that the two-factor model (Dissatisfaction with Appearance and Social Discomfort) demonstrated good fit based on the CFI and TLI indices, and slightly less than acceptable fit based on the RMSEA, x²(75)=742.33, p<.001, CFI=0.98, TLI=0.97, RMSEA=0.11. Statistically significant, but small-magnitude DIF was found for six SWAP items across socio-demographic or disease characteristics; however, the overall estimates in SWAP scores were not influenced substantively by DIF.

Conclusion: SWAP scores from male and female SSc patients, Black and White patients, and patients with diffuse and limited SSc can be compared and pooled without concern that measurement differences may substantially influence results. Replications of the current study with larger samples of male patients as well as Black and other/racial ethnic minority groups are needed.

Disclosure: L. Jewett, None; L. Kwakkenbos, None; V. L. Malcarne, None; M. E. Carrier, None; B. D. Thombs, None.

To cite this abstract in AMA style:

Jewett L, Kwakkenbos L, Malcarne VL, Carrier ME, Thombs BD. Confirmatory Factor Analysis and Assessment of Differential Item Functioning of the Satisfaction with Appearance Scale in Systemic Sclerosis: A Comparison Across Sex, Race/Ethnicity and Disease Subtype [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/confirmatory-factor-analysis-and-assessment-of-differential-item-functioning-of-the-satisfaction-with-appearance-scale-in-systemic-sclerosis-a-comparison-across-sex-raceethnicity-and-disease-subtyp/. Accessed .

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