Page 93 - THE PERCEPT STUDY Illness Perceptions in Physiotherapy Edwin de Raaij

Introduction
Musculoskeletal pain (MSP) is a major cause of increased years lived with disability 37. There are several generic factors prognostic of poor recovery from MSP 2: widespread pain (≥2 pain sites), high functional disability, somatization, and high pain intensity. Psychological factors such as distress, depressive mood and somatization have also been identified as risk factors for the transition from acute to chronic low back pain 8,12,18,14. These domains have been identified, but no recommendation can be made as to the best instrument for identifying these factors. In The Netherlands, the Four-Dimensional Symptom Questionnaire (4DSQ) is commonly used to assess distress, depression, anxiety and somatization 35. In addition, illness perceptions (IPs), as the core element of the Common-Sense Model of Self-regulation of Health and Illness (CSM), have been recognized as possible risk factors for poor recovery from MSP. The Brief Illness Perceptions Questionnaire (Brief IPQ) is frequently used to assess these IPs 7. A recent systematic review showed limited to moderate evidence for the association of some IPs with pain intensity (PI) and physical functioning (PF) in MSP 29. Pathways by which these associations can influence MSP are not known. IPs might act as moderators or mediators or affect MSP through fear avoidance or catastrophizing. Another important finding of the review was that longitudinal research is lacking. Therefore, it is desirable to explore the added predictive value of IPs, over and above the well-known generic factors for poor recovery from MSP, in the physiotherapy setting.
The CSM model provides a framework for identifying unhelpful cognitions and emotions people may have about their MSP condition 25. It is based on a parallel processing model, describing individual representations (i.e. IPs) in response to health threats (i.e. MSP). There are 9 IP dimensions included in the CSM: Consequences, Timeline, Personal Control, Treatment Control, Identity, Concern, Coherence, Emotional Response, and Causal 27,6.
To investigate the added predictive value of IPs, we used the term ‘predictor’ defined as: “A patient characteristic that identifies subgroups of treated patients having different out- comes” 1. In our study, IPs were seen as predictors, the treatment was usual care physiother- apy, and the disease was non-specific MSP.
Previous research has found that IPs are predictive for and associated with psychological factors, such as depression and anxiety, in patients with fibromyalgia 21, chronic back pain 11 systemic lupus erythematosus 28 and informal carers of patients with depression 31. Therefore, overlap may exist between the domains included in the 4DSQ and in the Brief IPQ. Because of this potential overlap, we were interested in the correlation of these questionnaires. We
A multi-center longitudinal study
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