Page 59 - THE PERCEPT STUDY Illness Perceptions in Physiotherapy Edwin de Raaij

A systematic literature review
One longitudinal study16 with a time interval of 6 to 12 months found limited evidence for illness perceptions being prognostic for more limitations in physical function on the dimensions of Timeline chronic, Treatment Control, and Identity (Appendix D).
Two longitudinal studies2,7 with a time interval of greater than 12 months, found moderate evidence for illness perceptions being prognostic for more limitations in physical function on the illness perception dimensions of Consequences, Personal Control, and Identity, and limited evidence for dysfunctional illness perceptions being prognostic for more limitations in physical function on the dimensions of Timeline-chronic, Concern, and Emotional Response (Appendix D).
Discussion
The aim of this study was to systematically review the relationship between illness perceptions and pain intensity or physical function in patients with musculoskeletal pain. For cross- sectional study designs, there is moderate evidence for all illness perception dimensions being positively associated with pain intensity and physical function. Overall, the evidence for the longitudinal relationship was less evident. For pain intensity, there is moderate evidence for the illness perception dimension of Consequences to be prognostic at a time interval of less than 6 months. For physical function, there is moderate evidence that the dimensions of Consequences, Timeline (chronic/cyclical), Personal Control, and Identity are prognostic factors for physical function at a time interval of less than 6 months. In addition, there is moderate evidence that the illness perception dimensions of Consequences, Personal Control, and Identity are prognostic factors for physial function at a time interval of greater than 12 months.
Across studies, the strength of associations and prognoses varied among all illness perception domains (Appendices A-D). The authors found no explanation for this variation, based on differences in number of participants, age, symptom duration, or the questionnaires used to assess illness perceptions, pain intensity, and physical function. Comparison of these findings with previous systematic reviews on illness perception and musculoskeletal pain is not possible, due to an absence of these studies in the scientific literature. Comparing the rel- evance of the present study’s results with other reviews in the field of illness perception, the authors found their results to be in line. In 2 meta-analyses on illness perception, the same sizes of associations are reported10,19. One study19 included a total of 23 illnesses (mostly nonmusculoskeletal) and outcome measures concerning physical health–related quality of life. The other study10 included a total of 31 conditions (varying from musculoskeletal to
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