Assessing differential item functioning for the Social Appearance Anxiety Scale: a Scleroderma atient-centred Intervention Network (SPIN) Cohort Study. Issue 10 (12th October 2020)

• Record Type: Journal Article
• Authors: Sommer, Sophia J; Harel, Daphna; Kwakkenbos, Linda; Carrier, Marie-Eve; Gholizadeh, Shadi; Gottesman, Karen; Leite, Catarina; Malcarne, Vanessa L; Thombs, Brett D
• Other Names: author non-byline.; Baron Murray author non-byline.; Bartlett Susan J author non-byline.; Furst Daniel E author non-byline.; Mayes Maureen D author non-byline.; Mouthon Luc author non-byline.; Nielson Warren R author non-byline.; Riggs Robert author non-byline.; Sauve Maureen author non-byline.; Wigley Fredrick author non-byline.; Assassi Shervin author non-byline.; Benedetti Andrea author non-byline.; Boutron Isabelle author non-byline.; Maia Angela Costa author non-byline.; Cronin Lindsay author non-byline.; El-Baalbaki Ghassan author non-byline.; Ells Carolyn author non-byline.; Elrod Stephen author non-byline.; Ende Cornelia van den author non-byline.; Fligelstone Kim author non-byline.; Fortune Catherine author non-byline.; Frech Tracy author non-byline.; Gietzen Amy author non-byline.; Godard Dominique author non-byline.; Geneviève Guillot Shirley Haslam author non-byline.; Hinchcliff Monique author non-byline.; Hudson Marie author non-byline.; Impens Ann author non-byline.; Jang Yeona author non-byline.; Johnson Sindhu R author non-byline.; Kennedy Ann Tyrell author non-byline.; Körner Annett author non-byline.; Larche Maggie author non-byline.; Marra Carlo author non-byline.; Nguyen Christelle author non-byline.; Nielsen Karen author non-byline.; Pope Janet author non-byline.; Portales Alexandra author non-byline.; Rannou François author non-byline.; Richard Michelle author non-byline.; Reyna Tatiana Sofia Rodriguez author non-byline.; Rozee Ken author non-byline.; Schouffoer Anne A. author non-byline.; Steele Russell J author non-byline.; Stephens Nancy author non-byline.; Suarez-Almazor Maria E author non-byline.; Welling Joep author non-byline.; Wong-Rieger Durhane author non-byline.; Agard Christian author non-byline.; Albert Alexandra author non-byline.; André Marc author non-byline.; Arsenault Guylaine author non-byline.; Benzidia Ilham author non-byline.; Bernstein Elana J author non-byline.; Berthier Sabine author non-byline.; Bissonnette Lyne author non-byline.; Boire Gilles author non-byline.; Bruns Alessandra author non-byline.; Carreira Patricia author non-byline.; Casadevall Marion author non-byline.; Chaigne Benjamin author non-byline.; Chung Lorinda author non-byline.; Cohen Pascal author non-byline.; Correia Chase author non-byline.; Dagenais Pierre author non-byline.; Denton Christopher author non-byline.; Domsic Robyn author non-byline.; Dubois Sandrine author non-byline.; Dunne James V author non-byline.; Dunogue Bertrand author non-byline.; Esquinca Alexia author non-byline.; Fare Regina author non-byline.; Farge-Bancel Dominique author non-byline.; Fortin Paul R author non-byline.; Gill Anna author non-byline.; Gordon Jessica author non-byline.; Granel-Rey Brigitte author non-byline.; Grange Claire author non-byline.; Gyger Genevieve author non-byline.; Hachulla Eric author non-byline.; Hatron Pierre-Yves author non-byline.; Hoa Sabrina author non-byline.; Herrick Ariane L author non-byline.; Hij Adrian author non-byline.; Ikic Alena author non-byline.; Jones Niall author non-byline.; Fernandes Artur Jose de B. author non-byline.; Kafaja Suzanne author non-byline.; Khalidi Nader author non-byline.; Lambert Marc author non-byline.; Launay David author non-byline.; Liang Patrick author non-byline.; Maillard Hélène author non-byline.; Maltez Nancy author non-byline.; Manning Joanne author non-byline.; Marie Isabelle author non-byline.; Martin Maria author non-byline.; Martin Thierry author non-byline.; Masetto Ariel author non-byline.; Maurier François author non-byline.; Mekinian Arsene author non-byline.; Melchor Sheila author non-byline.; Nikpour Mandana author non-byline.; Poindron Vincent author non-byline.; Proudman Susanna author non-byline.; Régent Alexis author non-byline.; Rivière Sébastien author non-byline.; Robinson David author non-byline.; Rodriguez Esther author non-byline.; Roux Sophie author non-byline.; Smets Perrine author non-byline.; Smith Doug author non-byline.; Sobanski Vincent author non-byline.; Spiera Robert author non-byline.; Steen Virginia author non-byline.; Stevens Wendy author non-byline.; Sutton Evelyn author non-byline.; Terrier Benjamin author non-byline.; Thorne Carter author non-byline.; Varga John author non-byline.; Wilcox Pearce author non-byline.; Bourgeault Angelica author non-byline.; Jiménez Andrea Carboni author non-byline.; Harb Sami author non-byline.; Tao Lydia author non-byline.;
• Is Part Of: BMJ open. Volume 10:Issue 10(2020)
• Publication Date: 2020-10-12
• Subjects: statistics & research methods -- rheumatology -- anxiety disorders; Medicine -- Research -- Periodicals; 610.72
• DOI: 10.1136/bmjopen-2020-037639
• Languages: English
• ISSNs: 2044-6055

Abstract

Abstract : Objectives: The Social Appearance Anxiety Scale (SAAS) is a 16-item questionnaire developed to evaluate fear of appearance-based evaluation by others. The primary objective of this research was to investigate the existence of differential item functioning (DIF) for the 16 SAAS items, comparing patients who completed the SAAS in English and French, either to confirm that scores are comparable or provide guidance on calculating comparable scores. A secondary research objective was to investigate the existence of DIF based on sex and disease status. A tertiary research objective was to assess DIF related to language, sex, and disease status on the recently developed SAAS-5. Design: This was a cross-sectional analysis using baseline data from patients enrolled in the Scleroderma Patient-centred Intervention Network (SPIN). Setting: SPIN patients included in the present study were enrolled at 43 centres in Canada, USA, UK, France and Australia, with questionnaires completed in April 2014 to July 2019. Participants: 1640 SPIN patients completed the SAAS in French (n=600) or English (n=1040). Primary and secondary measures: The SAAS was collected along with demographic and disease characteristics. Results: Six items were identified with statistically significant language-based DIF, four with sex-based DIF and one with disease type-based DIF. However, factor scores before and after accounting for DIF were similar (Pearson correlation >0.99), and individual score differences were small. This was true for both the full and shortened versions of the SAAS. Conclusion: SAAS and SAAS-5 scores are comparable across language, sex, and disease-type, despite small differences in how patients respond to some items.