Article Text

PDF

Factor structure and convergent validity of the Derriford Appearance Scale-24 using standard scoring versus treating ‘not applicable’ responses as missing data: a Scleroderma Patient-centered Intervention Network (SPIN) cohort study
  1. Erin L Merz1,
  2. Linda Kwakkenbos2,3,4,
  3. Marie-Eve Carrier2,
  4. Shadi Gholizadeh5,
  5. Sarah D Mills5,
  6. Rina S Fox5,6,
  7. Lisa R Jewett2,7,
  8. Heidi Williamson8,
  9. Diana Harcourt8,
  10. Shervin Assassi9,
  11. Daniel E Furst10,
  12. Karen Gottesman11,
  13. Maureen D Mayes9,
  14. Tim P Moss8,
  15. Brett D Thombs2,3,7,12,13,
  16. Vanessa L Malcarne5,14
  17. on behalf of the SPIN Investigators
    1. 1 Department of Psychology, California State University, Dominguez Hills, Carson, California, USA
    2. 2 Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
    3. 3 Department of Psychiatry, McGill University, Montreal, Quebec, Canada
    4. 4 Behavioral Science Institute, Clinical Psychology, Radboud University, Nijmegen, The Netherlands
    5. 5 San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, California, USA
    6. 6 Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
    7. 7 Department of Educational and Counseling Psychology, McGill University, Montreal, Quebec, Canada
    8. 8 Centre for Appearance Research, Faculty of Health and Life Science, University of the West of England, Bristol, UK
    9. 9 Department of Internal Medicine, Division of Rheumatology, University of Texas McGovern Medical School, Houston, Texas, USA
    10. 10 Division of Rheumatology, Geffen School of Medicine at the University of California, Los Angeles, California, USA
    11. 11 Scleroderma Foundation, Los Angeles, California, USA
    12. 12 Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada
    13. 13 Department of Medicine, McGill University, Montreal, Quebec, Canada
    14. 14 Department of Psychology, San Diego State University, San Diego, California, USA
    1. Correspondence to Dr Brett D Thombs; brett.thombs{at}mcgill.ca

    Abstract

    Objective Valid measures of appearance concern are needed in systemic sclerosis (SSc), a rare, disfiguring autoimmune disease. The Derriford Appearance Scale-24 (DAS-24) assesses appearance-related distress related to visible differences. There is uncertainty regarding its factor structure, possibly due to its scoring method.

    Design Cross-sectional survey.

    Setting Participants with SSc were recruited from 27 centres in Canada, the USA and the UK. Participants who self-identified as having visible differences were recruited from community and clinical settings in the UK.

    Participants Two samples were analysed (n=950 participants with SSc; n=1265 participants with visible differences).

    Primary and secondary outcome measures The DAS-24 factor structure was evaluated using two scoring methods. Convergent validity was evaluated with measures of social interaction anxiety, depression, fear of negative evaluation, social discomfort and dissatisfaction with appearance.

    Results When items marked by respondents as ‘not applicable’ were scored as 0, per standard DAS-24 scoring, a one-factor model fit poorly; when treated as missing data, the one-factor model fit well. Convergent validity analyses revealed strong correlations that were similar across scoring methods.

    Conclusions Treating ‘not applicable’ responses as missing improved the measurement model, but did not substantively influence practical inferences that can be drawn from DAS-24 scores. Indications of item redundancy and poorly performing items suggest that the DAS-24 could be improved and potentially shortened.

    • derriford appearance scale
    • Das-24
    • systemic sclerosis
    • psychometrics
    • confirmatory factor analysis

    This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/

    View Full Text

    Statistics from Altmetric.com

    Footnotes

    • Contributors ELM, LK, BDT and VLM were responsible for the study concept and design, data analysis and interpretation and drafting the manuscript. LK, MEC, SG, SDM, RSF, LRJ, HW, DH, SA, DEF, KG, MDM, TPM, BDT, VLM and SPIN were responsible for data collection. All authors were responsible for the critical revision and final approval of the manuscript. ELM is the guarantor.

    • Funding The Scleroderma Patient-centered Intervention Network (SPIN) is funded by the Canadian Institutes of Health Research (CIHR; PI=Thombs, TR3-119192; PI=Thombs, PJT- 148504; PIs=Thombs, Mouthon, Poiraudeau, PJT-149073) and the Arthritis Society (SOG-16- 380, PI=Thombs). In addition, SPIN has received institutional contributions from the Lady Davis Institute for Medical Research of the Jewish General Hospital, Montreal, Quebec, Canada and from McGill University, Montreal, Canada. SPIN has also received support from the Scleroderma Society of Ontario, Scleroderma Canada and Sclérodermie Quebec. LK was supported by a CIHR Banting Postdoctoral Fellowship. RSF was supported by a National Cancer Institute Training Grant (5T32CA193193). LRJ was supported by a CIHR Doctoral Research Award. BDT was supported by an Investigator Salary Award from the Arthritis Society.

    • Competing interests The authors have read and understood the BMJ policy on declaration of interests and declare the following interests: the DAS-24 is commercially available from TPM.

    • Patient consent Detail has been removed from this case description/these case descriptions to ensure anonymity. The editors and reviewers have seen the detailed information available and are satisfied that the information backs up the case the authors are making.

    • Ethics approval Research Ethics Committee of the Jewish General Hospital, Montreal, Canada and by the Institutional Reviews Boards of each participating center.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Data sharing statement Anonymised patient level DAS-24 data from the SPIN sample are evaluated by the SPIN steering committee and are available on reasonable request. Anonymised patient level DAS-24 data from the Visible Difference sample (15) are available from the Peer journal website at https://peerj.com/articles/1070/#supplemental-information.

    • Collaborators SPIN Investigators: Murray Baron, McGill University, Montreal, Quebec, Canada; Susan J Bartlett, McGill University, Montreal, Quebec, Canada; Frank van den Hoogen, Radboud University Medical Center and Sint Maartenskliniek, Nijmegen, The Netherlands; Luc Mouthon, Université Paris Descartes, Paris, France; Warren R Nielson, St. Joseph’s Health Care, London, Ontario, Canada; Robert Riggs, Scleroderma Foundation, Danvers, Massachusetts, USA; Maureen Sauve, Scleroderma Society of Ontario, Hamilton, Ontario; Fredrick Wigley, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Isabelle Boutron, Université Paris Descartes, and Assistance Publique Hôpitaux de Paris, Paris, France; Angela Costa Maia, University of Minho, Braga, Portugal; Ghassan El-Baalbaki, Université du Québec à Montréal, Montreal, Quebec, Canada; Carolyn Ells, McGill University, Montreal, Quebec, Canada; Cornelia van den Ende, Sint Maartenskliniek, Nijmegen, The Netherlands; Kim Fligelstone, Scleroderma Society, London, UK; Catherine Fortune, Scleroderma Society of Ontario, Hamilton, Ontario, Canada; Tracy Frech, University of Utah, Salt Lake City, Utah, USA; Dominique Godard, Association des Sclérodermiques de France, Sorel-Moussel, France; Daphna Harel, New York University, New York, New York, USA; Marie Hudson, McGill University, Montreal, Quebec, Canada; Ann Impens, Midwestern University, Downers Grove, Illinois, USA; Yeona Jang, McGill University, Montreal, Quebec, Canada; Sindhu R Johnson, Toronto Scleroderma Program, Mount Sinai Hospital, Toronto Western Hospital, and University of Toronto, Toronto, Ontario, Canada; Ann Tyrell Kennedy, Federation of European Scleroderma Associations, Dublin, Ireland; Annett Körner, McGill University, Montreal, Quebec, Canada; Maggie Larche, McMaster University, Hamilton, Ontario, Canada; Catarina Leite, University of Minho, Braga, Portugal; Carlo Marra, Memorial University, St. John’s, Newfoundland, Canada; Karen Nielsen, Scleroderma Society of Ontario, Hamilton, Ontario, Canada; Janet Pope, University of Western Ontario, London, Ontario, Canada; Alexandra Portales, Asociación Española de Esclerodermia, Madrid, Spain; Tatiana Sofia Rodriguez Reyna, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico; Anne A Schouffoer, Leiden University Medical Center, Leiden, The Netherlands; Russell J Steele, Jewish General Hospital and McGill University, Montreal, Quebec, Canada; Maria E Suarez-Almazor, University of Texas MD Anderson Cancer Center, Houston, Texas, USA; Joep Welling, NVLE Dutch patient organisation for systemic autoimmune diseases, Utrecht, The Netherlands; Durhane Wong-Rieger, Canadian Organisation for Rare Disorders, Toronto, Ontario, Canada; Christian Agard, Centre Hospitalier Universitaire-Hôtel-Dieu de Nantes, Nantes, France; Alexandra Albert, Université Laval, Quebec, Quebec, Canada; Marc André,Centre Hospitalier Universitaire Gabriel-Montpied, Clermont-Ferrand, France; Guylaine Arsenault, Université de Sherbrooke , Sherbrooke, Quebec, Canada; Nouria Benmostefa, Assistance Publique Hôpitaux de Paris-Hôpital Cochin, Paris, France; Ilham Benzida, Assistance Publique Hôpitaux de Paris-Hôpital St-Louis, Paris, France; Sabine Berthier, Centre Hospitalier Universitaire Dijon Bourgogne, Dijon, France; Lyne Bissonnette, Université de Sherbrooke , Sherbrooke, Quebec, Canada; Gilles Boire, Université de Sherbrooke, Sherbrooke, Quebec, Canada; Alessandra Bruns, Université de Sherbrooke, Sherbrooke, Quebec, Canada; Patricia Carreira, Servicio de Reumatologia del Hospital 12 de Octubre, Madrid, Spain; Marion Casadevall, Assistance Publique Hôpitaux de Paris-Hôpital Cochin, Paris, France; Benjamin Chaigne, Assistance Publique Hôpitaux de Paris-Hôpital Cochin, Paris, France; Lorinda Chung, Stanford University, Stanford, California, USA; Pascal Cohen, Assistance Publique Hôpitaux de Paris-Hôpital Cochin, Paris, France; Pierre Dagenais, Université de Sherbrooke, Sherbrooke, Quebec, Canada; Christopher Denton, Royal Free London Hospital, London, UK; Robyn Domsic, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; James V Dunne, St. Paul’s Hospital and University of British Columbia, Vancouver, British Columbia, Canada; Dominique Farge-Bancel, Assistance Publique Hôpitaux de Paris-Hôpital St-Louis, Paris, France; Paul Fortin, Université Laval, Quebec, Quebec, Canada; Anna Gill, Royal Free London Hospital, London, UK; Jessica Gordon, Hospital for Special Surgery, New York City, New York, USA; Brigitte Granel-Rey, Aix Marseille Université, and Assistance Publique Hôpitaux de Marseille-Hôpital Nord, Marseille, France; Claire Grange, Centre Hospitalier Lyon Sud, Lyon, France; Genevieve Gyger, Jewish General Hospital and McGill University, Montreal, Quebec, Canada; Eric Hachulla, Centre Hospitalier Régional Universitaire de Lille -Hôpital Claude Huriez, Lille, France; Pierre-Yves Hatron, Centre Hospitalier Régional Universitaire de Lille-Hôpital Claude Huriez, Lille, France; Ariane L Herrick, University of Manchester, Salford Royal NHS Foundation Trust, Manchester, UK; Adrian Hij, Assistance Publique Hôpitaux de Paris-HôpitalSt-Louis, Paris, France; Monique Hinchcliff, Northwestern University, Chicago, Illinois, USA; Alena Ikic, Université Laval, Quebec, Quebec, Canada; Niall Jones, University of Alberta, Edmonton, Alberta, Canada; Artur Jose de B Fernandes, Université de Sherbrooke, Sherbrooke, Quebec, Canada; Suzanne Kafaja, University of California, Los Angeles, California, USA; Nader Khalidi, McMaster University, Hamilton, Ontario, Canada; Benjamin Korman, Northwestern University, Chicago, Illinois, Marc Lambert, Centre Hospitalier Régional Universitaire de Lille-Hôpital Claude Huriez, Lille, France; David Launay, Centre Hospitalier Régional Universitaire de Lille-Hôpital Claude Huriez, Lille, France; USA; Patrick Liang, Université de Sherbrooke, Sherbrooke, Quebec, Canada; Jonathan London, Assistance Publique Hôpitaux de Paris-Hôpital Cochin, Paris, France; Joanne Manning, Salford Royal NHS Foundation Trust, Salford, UK; Thierry Martin, Les Hôpitaux Universitaires de Strasbourg-Nouvel Hôpital Civil, Strasbourg, France; Ariel Masetto, Université de Sherbrooke, Sherbrooke, Quebec, Canada; Arsene Mekinian, Assistance Publique Hôpitaux de Paris-Hôpital St-Antoine, Paris, France; Romain Paule, Assistance Publique Hôpitaux de Paris-Hôpital Cochin, Paris, France; Alexis Regent, Assistance Publique Hôpitaux de Paris-Hôpital Cochin, Paris, France; Sébastien Rivière, Assistance Publique Hôpitaux de Paris-Hôpital St-Antoine, Paris, France; David Robinson, University of Manitoba, Winnipeg, Manitoba, Canada; Sophie Roux, Université de Sherbrooke, Sherbrooke, Quebec, Canada; Perrine Smets, Centre Hospitalier Universitaire Gabriel-Montpied, Clermont-Ferrand, France; Doug Smith, University of Ottawa, Ottawa, Ontario, Canada; Vincent Sobanski, Centre Hospitalier Régional Universitaire de Lille-Hôpital Claude Huriez, Lille, France; Robert Spiera, Hospital for Special Surgery, New York, New York, USA; Virginia Steen, Georgetown University, Washington, DC, USA; Evelyn Sutton, Dalhousie University, Halifax, Nova Scotia, Canada; Benjamin Terrier, Assistance Publique Hôpitaux de Paris-Hôpital Cochin, Paris, France; Carter Thorne, Southlake Regional Health Centre, Newmarket, Ontario, Canada; John Varga, Northwestern University, Chicago, Illinois, USA; Pearce Wilcox, St. Paul’s Hospital and University of British Columbia, Vancouver, British Columbia, Canada; Vanessa C Delisle, Jewish General Hospital and McGill University, Montreal, Quebec, Canada; Brooke Levis, Jewish General Hospital and McGill University, Montreal, Quebec, Canada; Mia R Pepin, Jewish General Hospital, Montreal, Quebec, Canada.

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.