title: The discordance between subjectively and objectively measured physical function in women with fibromyalgia: association with catastrophizing and self-efficacy cognitions. The al-Ándalus project.
abstract: OBJECTIVE
  People with fibromyalgia experience a disagreement between patient-reported (i.e., subjective) and performance-based (i.e., objective) status. This study aimed to (i) corroborate the discordance between subjectively and objectively measured physical function and (ii) examine whether catastrophizing (worrying, pain magnifying, and helpless cognitions) and self-efficacy (believing capable to manage pain) are independently associated with this discordance.
  
  
  METHODS
  This population-based cross-sectional study included 405 women with fibromyalgia and 193 age-matched female controls. Participants completed the Pain Catastrophizing Scale, Chronic Pain Self-efficacy Scale, and physical functioning subscales of the Revised Fibromyalgia Impact Questionnaire and Short Form-36 (SF-36) health survey. Objective physical function was measured with the Senior Fitness Test battery. Subjective and objective physical functions were expressed as deviation from the general population in standard deviation (SD) units using means and SD of the control group.
  
  
  RESULTS
  In fibromyalgia, subjective physical function was worse than objective physical function (p < 0.001). Higher catastrophizing was consistently associated with greater discordance between subjective and objective physical function, while self-efficacy was only significantly associated with this discordance when subjective physical function was assessed by means of the SF-36.
  
  
  CONCLUSIONS
  Subjective physical function is more impaired than objective physical function in fibromyalgia, yet both are markedly impaired. Catastrophizing cognitions are associated with this discordance. In particular, high catastrophizing may promote a feeling of reduced ability to do meaningful activities of daily living (i.e., restrictions) that people with fibromyalgia are actually able to. Therefore, catastrophizing should be assessed and potentially targeted when focusing on improving physical function in fibromyalgia. Implications for rehabilitation Rehabilitation should focus on physical exercise programs to help women with fibromyalgia to improve their reduced physical function. In rehabilitation settings, physical function of people with fibromyalgia should be evaluated by both subjective and objective assessments to fully understand physical functioning and to test the existence of discordance between both assessments. In case of a large discordance between subjective and objective physical function, a physical exercise program might be better complemented with cognitive management techniques to reduce catastrophizing and subjective physical dysfunction. When people with fibromyalgia experience high levels of catastrophizing, subjective assessments seem to be poor indicators of physical function.
authors.affiliation: a Department of Physical Education and Sport, Faculty of Sport Sciences , University of Granada , Granada , Spain.|b Department of Psychology, Faculty of Social and Behavioural Sciences , Utrecht University , Utrecht , The Netherlands.
authors.forename: Fernando
authors.identifier: http://orcid.org/0000-0003-2960-4142
authors.initials: F
authors.lastname: Estévez-López
authors.affiliation: a Department of Physical Education and Sport, Faculty of Sport Sciences , University of Granada , Granada , Spain.|c Department of Physical Education, Faculty of Education Sciences , University of Cádiz , Cádiz , Spain.
authors.forename: Inmaculada C
authors.identifier: http://orcid.org/0000-0002-1062-8251
authors.initials: IC
authors.lastname: Álvarez-Gallardo
authors.affiliation: a Department of Physical Education and Sport, Faculty of Sport Sciences , University of Granada , Granada , Spain.|c Department of Physical Education, Faculty of Education Sciences , University of Cádiz , Cádiz , Spain.
authors.forename: Víctor
authors.identifier: http://orcid.org/0000-0001-8655-9857
authors.initials: V
authors.lastname: Segura-Jiménez
authors.affiliation: a Department of Physical Education and Sport, Faculty of Sport Sciences , University of Granada , Granada , Spain.|d Department of Education, Faculty of Education Sciences , University of Almería , Almería , Spain.
authors.forename: Alberto
authors.identifier: http://orcid.org/0000-0002-4626-420X
authors.initials: A
authors.lastname: Soriano-Maldonado
authors.affiliation: a Department of Physical Education and Sport, Faculty of Sport Sciences , University of Granada , Granada , Spain.
authors.forename: Milkana
authors.identifier: http://orcid.org/0000-0002-8276-9387
authors.initials: M
authors.lastname: Borges-Cosic
authors.affiliation: e Department of Psychology, Faculty of Humanities and Sciences of Education , University of Jaén , Jaén , Spain.
authors.forename: Manuel
authors.identifier: http://orcid.org/0000-0002-9274-3682
authors.initials: M
authors.lastname: Pulido-Martos
authors.affiliation: f Department of Physiology, Faculty of Pharmacy, Faculty of Sport Sciences, and Institute of Nutrition and Food Technology , University of Granada , Granada , Spain.|g Department of Public and Occupational Health , EMGO + Institute for Health and Care Research, VU University Medical Centre , Amsterdam , The Netherlands.
authors.forename: Virginia A
authors.identifier: http://orcid.org/0000-0003-1762-2925
authors.initials: VA
authors.lastname: Aparicio
authors.affiliation: c Department of Physical Education, Faculty of Education Sciences , University of Cádiz , Cádiz , Spain.
authors.forename: Ana
authors.identifier: http://orcid.org/0000-0003-1762-2925
authors.initials: A
authors.lastname: Carbonell-Baeza
authors.affiliation: a Department of Physical Education and Sport, Faculty of Sport Sciences , University of Granada , Granada , Spain.
authors.forename: Manuel
authors.identifier: http://orcid.org/0000-0003-0636-9258
authors.initials: M
authors.lastname: Delgado-Fernández
authors.affiliation: b Department of Psychology, Faculty of Social and Behavioural Sciences , Utrecht University , Utrecht , The Netherlands.
authors.forename: Rinie
authors.identifier: http://orcid.org/0000-0002-6615-6708
authors.initials: R
authors.lastname: Geenen
mesh_terms: D016022:Case-Control Studies; D058443:Catastrophization; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005080:Exercise Test; D005260:Female; D005356:Fibromyalgia / Q000523:psychology*; D006801:Humans; D008875:Middle Aged; D010809:Physical Fitness / Q000523:psychology*; D020377:Self Efficacy
keywords: Chronic pain; disability; functional capacity; functional fitness; observed physical function; self-reported physical function