Page 138 - THE PERCEPT STUDY Illness Perceptions in Physiotherapy Edwin de Raaij

Chapter 7
Discussion
In this matched-care physiotherapy treatment for patients with persistent LBP SCED-study, we showed a statistically significant and clinically meaningful improvement in decreasing pain intensity, increased physical function and lesser pain interference in daily life during and three months post-treatment. We did not observe a wash-out phenomenon during the post treatment phase. Furthermore, we found five IP dimensions mediating the effect on all three primary outcomes; namely, Consequences (45.2-56.3) Personal control (8.1-15.7), Iden- tity (46.7-52.9), Concern (15.6-34.3) and Emotional response (24.3-38.9). At baseline, the IP Personal control acted as a moderator for all primary outcomes. In the post treatment phase the IPs Personal Control, Identity, Concern and Emotional response also acted as moderator.
Illness Perceptions as mediator
The search for causal mechanisms for non-specific LBP has been a quest for decades now21,27. Identifying such mechanisms is useful, for instance, when designing a ‘Magic Bullet’ cure, for a condition that is primarily caused by a pathoanatomical impairment11. In the case of persistent musculoskeletal pain like LBP, such pathoanatomical impairment most likely cannot be identified. LBP is considered to be a symptom of a complex condition with multiple con- tributors to both pain and associated limitations in physical function, including psychological factors, social factors, biophysical factors, co-morbidities, and pain-processing mechanisms17. Models for management of complex conditions should incorporate these multiple contrib- utors, including patients’ beliefs about their condition3,7. IPs are thought of as one aspect of these beliefs3. Through mediation analyses we identified five IP dimensions that mediated the total effect of our matched-care physiotherapy treatment package. Intervention studies on how to alter IPs in LBP are scarce. We know of one RCT that looked at altering baseline IPs with cognitive treatment to improve patient relevant physical activities36. In this study IP di- mensions Timeline cyclical, Consequences, Personal control and Coherence attributed 14.4% of the explained variance to physical activities. This partly overlaps with our results. We found IP dimensions Consequences and Personal control also significantly mediating the total effect on all three primary outcomes.
The effects in our study are found within a non-controlled design and should be further test- ed in a larger population and with a different design such as a randomized controlled trial.
Illness Perceptions as moderator
The course and prognosis of developing persistent LBP have been extensively researched7. The overall findings are reported as; “Low to moderate levels of pain and disability were still present at one year, especially in the cohorts with persistent pain.” In a Cochrane review on
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