Abstract
Objective: Systemic sclerosis (SSc) is an autoimmune disease that can cause disfiguring changes in appearance. This study examined the structural validity, internal consistency reliability, convergent validity, and measurement equivalence of the Social Appearance Anxiety Scale (SAAS) across SSc disease subtypes. Methods: Patients enrolled in the Scleroderma Patient-centered Intervention Network Cohort completed the SAAS and measures of appearance-related concerns and psychological distress. Confirmatory factor analysis (CFA) was used to examine the structural validity of the SAAS. Multiple-group CFA was used to determine whether SAAS scores can be compared across patients with limited and diffuse disease subtypes. Cronbach's alpha was used to examine internal consistency reliability. Correlations of SAAS scores with measures of body image dissatisfaction, fear of negative evaluation, social anxiety, and depression were used to examine convergent validity. SAAS scores were hypothesized to be positively associated with all convergent validity measures, with correlations significant and moderate to large in size. Results: A total of 938 patients with SSc were included. CFA supported a 1-factor structure (Comparative Fit Index 0.92, Standardized Root Mean Residual 0.04, and Root Mean Square Error of Approximation 0.08), and multiple-group CFA indicated that the scalar invariance model best fit the data. Internal consistency reliability was good in the total sample (α = 0.96) and in disease subgroups. Overall, evidence of convergent validity was found with measures of body image dissatisfaction, fear of negative evaluation, social anxiety, and depression. Conclusion: The SAAS can be reliably and validly used to assess fear of appearance evaluation in patients with SSc, and SAAS scores can be meaningfully compared across disease subtypes.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1557-1562 |
| Number of pages | 6 |
| Journal | Arthritis Care and Research |
| Volume | 70 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2018 |
Funding
The CFI was used to statistically compare increasingly restrictive models for the multiple-group CFA. A change in CFI of \u22640.01 was indicative of no difference between models. Internal consistency reliability was examined using Cronbach's coefficient alpha. Convergent validity was examined via Pearson's product-moment correlations of the SAAS and measures of depression (PHQ-8), body image dissatisfaction (Brief-SWAP), and social anxiety (BFNE-II, SIAS-6). Fisher's z was used to statistically compare correlation coefficients among convergent validity variables. The Scleroderma Patient-centered Intervention Network is supported by the Canadian Institutes of Health Research (TR3-119192, PJT-148504, and PJT-149073), the Arthritis Society, the Lady Davis Institute for Medical Research of the Jewish General Hospital, McGill University, the Scleroderma Society of Ontario, Scleroderma Canada, and Scl\u00E9rodermie Qu\u00E9bec. Dr. Kwakkenbos\u2019s work was supported by a Canadian Institutes of Health Research Banting Postdoctoral Fellowship. Ms Jewett\u2019s work was supported by a Canadian Institutes of Health Research Doctoral Research Award. Dr. Thombs\u2019 work was supported by a Fonds de Recherche du Qu\u00E9bec\u2013Sant\u00E9 researcher salary award.
ASJC Scopus subject areas
- Rheumatology