Page 86 - THE PERCEPT STUDY Illness Perceptions in Physiotherapy Edwin de Raaij

Chapter 4
ranging sample in the Netherlands, selection bias may exist since there is no information available regarding patients that did not sign an informed consent form and were therefore not included in this study. Thirdly, bias on the outcomes of pain duration cannot be excluded since these rely on the recall of the patients, which has been found to be unreliable. Patients with persistent MSP have to search further back in their memory than those with acute MSP, thereby producing less reliable data12. Fourthly, the well-known prognostic factors did not contribute to the model. This may be explained by the fact that we chose well-known prognostic factors from studies on chronicity of MSP. We did not find studies on prognostic factors for pain intensity in MSP so we hypothesized that prognostic factors for chronicity might also be factors that mediate in the association of IPs with pain intensity and physical functioning. Our findings suggest that most prognostic factors for chronicity of MSP do not mediate the association between IPs, pain intensity and physical functioning.
A major strength of our study is its multi-centred basis in the primary care setting throughout the Netherlands. This means that the MSP population in this research can be compared with patients attending any general physiotherapist in the Netherlands, and results can be generalized to the Dutch MSP patients visiting physiotherapists. Secondly, for prognostic studies, Hayden et al. proposed a three-phase framework: “Phase 1, identifying associations; Phase 2, testing independent associations; and Phase 3, understanding prognostic pathways”15. We have performed the first Phase 2 study exploring the cross-sectional independent association of IPs with pain intensity and physical functioning in primary physiotherapy care. We recommend further exploration of these pathways in a Phase 3 explanatory study, where IPs are explored longitudinally for their predictive value for pain intensity and physical functioning.
Practical implications
Dysfunctional beliefs about MSP may contribute to pain intensity and limitations in physical functioning. Higher IP scores on Consequences, Identity and Coherence were associated with higher pain intensity. Higher IP scores on Consequences, Treatment Control, Identity and Concern were associated with greater limitations in physical functioning. Due to the cross- sectional design of our study, a causal interpretation is not possible in patients with MSP, but this has already been shown in cohorts of patients with persistent pain from repetitive strain injury26 and low back pain4. This highlights the therapeutic potential of targeting higher IP scores and trying to alter dysfunctional IPs to more favourable, adaptive, ones. Changing IPs is not only relevant for alleviating the burden of MSP, but also for reducing dependence on physiotherapy treatment. Higher scores on IPs are associated with more frequent use of physiotherapy21. Finally, our study calls for a Phase 3 explanatory study in which the IPs are explored
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