Outcomes of Interdisciplinary Pain Rehabilitation Across Subgroups of the Multidimensional Pain Inventory – A Study From the Swedish Quality Registry for Pain Rehabilitation

Abstract

Introduction: The Multidimensional Pain Inventory (MPI) is frequently used in the assessment of chronic pain. Three subgroups have been derived from MPI: adaptive coper (AC), dysfunctional (DYS), and interpersonally distressed (ID). The primary aim of this study was to examine whether outcome of Interdisciplinary Multimodal Pain Rehabilitation Programs (IMMRPs) differed across the MPI subgroups. Methods: Patients with chronic pain (N = 34,513), included in the Swedish Quality Registry for Pain Rehabilitation, were classified into MPI subgroups and a subset that participated in IMMRPs (N = 13,419) was used to examine overall treatment outcomes using a previously established Multivariate Improvement Score (MIS) and 2 retrospective patient-evaluated benefits from treatment. Results: The subgroups differed on sociodemographic characteristics, pain duration, and spatial spreading of pain. DYS and ID had the best overall outcomes to MIS. AC had the best outcomes according to the 2 retrospective items. Transition into other subgroups following IMMRP was common and most prominent in DYS and least prominent in AC. Conclusion:The validity of the MPI subgroups was partially confirmed. DYS and ID had the most severe clinical presentations at baseline and showed most improvement following IMMRP, but overall severity in DYS and ID at post-treatment was still higher than in the AC group. Future studies should examine how processes captured by MPI interact with neurobiological, medical, sociodemographic, and adaptation/coping factors and how these interactions impact severity of chronic pain and treatment outcome. &

Perspective Chapter: Interdisciplinary Pain Rehabilitation Programs – Evidence and Clinical Real-World Results

“…However, the subgroup with the most severe clinical situation was somewhat underrepresented [70,89]. Similar results were found for the DYS subgroup of MPI, male gender, and the non-European subgroup [75,87]. In agreement with this SQRP, data from two university hospital departments showed negative correlations between participation/selection and pain intensity but positive correlations with pain extent [90].…”

“…However, a similar pattern was not displayed in two large-scale SQRP cohort studies where patients reporting higher levels of perceived disability and suffering displayed slightly greater improvement [27,70]. Hence, those with the most severe clinical presentations at baseline will display the largest improvements found in SQRP studies [70,71,75].…”

“…The Multidimensional Pain Inventory (MPI) classifies patients into subgroups [73,74]. These subgroups-Adaptive Coper (AC), Dysfunctional (DYS), and Interpersonally Distressed (ID)-were identified in a large cohort from the SQRP (N = 34 513) and the validity of these subgroups of MPI was partially confirmed [75]. However, in contrast to results reported by Turk and Rudy, the subgroups differed in socio-demographic characteristics, pain duration, and pain extent [73].…”

“…Some reports suggest that the DYS and/or ID subgroups have better treatment outcomes than the AC group [109,[112][113][114][115][116], whereas other studies have found no significant differences in outcomes amongst subgroups [110,111,[117][118][119][120][121]. These results are supported by a large-scale cohort study from the SQRP: DYS and ID subgroups that had the most severe clinical presentation at baseline showed the largest improvement following IPRP [75].…”

Classifying chronic pain using multidimensional pain-agnostic symptom assessments and clustering analysis

“…The subgroups initially developed using patients with heterogeneous chronic pain, later reproduced in other chronic pain diagnostic groups, such as low back pain, headache, and patients with temporomandibular disorder (TMD) (40). Mixed effects were found for the potential association between MPI-based classification and treatment outcomes (41)(42)(43)(44).…”