Page 139 - THE PERCEPT STUDY Illness Perceptions in Physiotherapy Edwin de Raaij

individual recovery expectations it is concluded: “Our findings suggest that recovery expec- tations should be considered in future studies, to improve prognosis and management of low back pain”18. We found the IP dimension Personal control to be moderating the effect on all three primary outcomes. This IP dimension can be seen as reflecting patients’ expecta- tions about the effect of the treatment. We therefore would like to advise to consider the IP Personal control in future research concerning treatment and prognosis of LBP.
Study limitations
Several limitations need to be considered. First, there was no randomization. The effects in our study are found within a non-controlled design. We explicitly focused on a ‘matched care intervention’. Meaning that the intervention was tailored on the patients’ clinical presenta- tion, and therefore randomization was not included in our design. Secondly, selection bias of patients. The patients were selected by the participating physiotherapists, therefore the generalizability of our results is somewhat limited. Thirdly, patients were required to complete a questionnaire, monitoring their progress on a weekly basis for several months. This may have given rise to the awareness of being studied. This possibly impacted behavior, resulting in a Hawthorne effect28. Fourthly, there is a potential sampling bias of treating / participating physiotherapists due to the use of convenience sampling of physiotherapists via social media and within the network of the first author. They were invited to our two-day course to be informed on the design of the study. These physiotherapists might not be representative of the physiotherapy community in the Netherlands. Fifthly, we do not have data to analyze the treatment fidelity of participating physiotherapists on delivering the matched-care treatment package. The weight this has on the effects is not clear. We tried to minimize this limitation by including several implementation interventions addressing fidelity of the physiotherapists to participate in the study: a two day course, videos were accessible demonstrating how to apply treatment strategies and the use of repeated measures during the treatment phase. Finally, due to the design of this study conclusions about causal relations between IPs and the primary outcome cannot be drawn. Further studies on the temporal order of the associations between matched-care physiotherapy, IPs and treatment outcomes are recommended.
Study strengths
There are several strengths of this study to be considered. First, the use of repeated meas- ures and a matched-care intervention instead of a strict treatment protocol allowed the phys- iotherapists to adjust their interventions to the clinical status of the patient with each new appointment. This dynamic and cyclical process is commonly used by physiotherapists and is a reflection of their clinical reasoning process13, making this design representative for daily practice. For example, if the patient shows a sufficient decrease of safety behaviors, than
A multiple baseline single-case experimental design
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