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

Purpose: 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.

Keywords:

• Chronic pain
• disability
• functional capacity
• functional fitness
• observed physical function
• self-reported physical function

Acknowledgements

The authors gratefully acknowledge all participants for their collaboration. We would like to thank researchers and collaborators involved in the al-Ándalus project and to all members of the Physical Activity for Health Promotion (PA-HELP; CTS-1018) research group.

Disclosure statement

The authors report no conflicts of interest. All the authors were involved in undertaking the research and take responsibility for the final manuscript.

Additional information

Funding

This work was supported by the Spanish Ministry of Economy and Competitiveness [I + D + i DEP2010–15639, I + D + i DEP2013–40908-R to MD-F; BES-2014–067612 to FE-L, BES-2011–047133 to ICA-G]; the University of Granada and CEI BioTic Granada [Mobility grant to FE-L]; the Consejería de Turismo, Comercio y Deporte, Junta de Andalucía [CTCD-201000019242-TRA to MD-F]; the Spanish Ministry of Education [FPU2014/02518 to MB-C]; the Andalucía Talent Hub Program launched by the Andalusian Knowledge Agency, co-funded by the European Union’s Seventh Framework Program, Marie Skłodowska-Curie actions and the Ministry of Economy, Innovation, Science and Employment of the Junta de Andalucía [COFUND – Grant Agreement no. 291780 to VAA]. All grants were unrestricted; the funding agencies did not have any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.