The importance of emotional distress, cognitive behavioural factors and pain for life impact at baseline and for outcomes after rehabilitation – a SQRP study of more than 20,000 chronic pain patients
Authors: Gerdle Björn , Åkerblom Sophia , Stålnacke Britt-Marie , Brodda Jansen Gunilla , Enthoven Paul , Ernberg Malin , Dong Huan-Ji , Äng Björn O , Boersma Katja 
Published: May 2019

Abstract

Background and aims
Although literature concerning chronic pain patients indicates that cognitive behavioural variables, specifically acceptance and fear of movement/(re)injury, are related to life impact, the relative roles of these factors in relation to pain characteristics (e.g. intensity and spreading) and emotional distress are unclear. Moreover, how these variables affect rehabilitation outcomes in different subgroups is insufficiently understood. This study has two aims: (1) to investigate how pain, cognitive behavioural, and emotional distress variables intercorrelate and whether these variables can regress aspects of life impact and (2) to analyse whether these variables can be used to identify clinically meaningful subgroups at baseline and which subgroups benefit most from multimodal rehabilitation programs (MMRP) immediately after and at 12-month follow-up.

Methods
Pain aspects, background variables, psychological distress, cognitive behavioural variables, and two life impact variables were obtained from the Swedish Quality Registry for Pain Rehabilitation (SQRP) for chronic pain patients. These data were analysed mainly using advanced multivariate methods.

Results
The study includes 22,406 chronic pain patients. Many variables, including acceptance variables, showed important contributions to the variation in clinical presentations and in life impacts. Based on the statistically important variables considering the clinical presentation, three clusters/subgroups of patients were identified at baseline; from the worst clinical situation to the relatively good situation. These clusters showed significant differences in outcomes after participating in MMRP; the subgroup with the worst situation at baseline showed the most significant improvements.

Conclusions
Pain intensity/severity, emotional distress, acceptance, and life impacts were important for the clinical presentation and were used to identify three clusters with marked differences at baseline (i.e. before MMRP). Life impacts showed complex relationships with acceptance, pain intensity/severity, and emotional distress. The most significant improvements after MMRP were seen in the subgroup with the lowest level of functioning before treatment, indicating that patients with complex problems should be offered MMRP.

Implications
This study emphasizes the need to adopt a biopsychosocial perspective when assessing patients with chronic pain. Patients with chronic pain referred to specialist clinics are not homogenous in their clinical presentation. Instead we identified three distinct subgroups of patients. The outcomes of MMRP appears to be related to the clinical presentation. Thus, patients with the most severe clinical presentation show the most prominent improvements. However, even though this group of patients improve they still after MMRP show a complex situation and there is thus a need for optimizing the content of MMRP for these patients. The subgroup of patients with a relatively good situation with respect to pain, psychological distress, coping and life impact only showed minor improvements after MMRP. Hence, there is a need to develop other complex interventions for them.