Moderate and Stable Pain Reductions as a Result of Interdisciplinary Pain Rehabilitation-A Cohort Study from the Swedish Quality Registry for Pain Rehabilitation (SQRP)

Outpatient interdisciplinary multimodal pain treatment programme for patients with chronic musculoskeletal pain: a longitudinal cohort study

PURPOSE

To describe the outcomes of an interdisciplinary multimodal pain treatment (IMPT) for chronic musculoskeletal pain (CMP) patients up until 12 months post-treatment.

MATERIALS AND METHODS

Data were gathered during routine clinical practice during a 3-year period (2019-2021) at six Dutch rehabilitation centres. Assessments included patient-reported outcome measures for multiple domains including disability, pain and fatigue. Longitudinal data were analysed using repeated-measures models and by quantifying responder rates.

RESULTS

Included were 2309 patients with a mean age of 43.7 (SD 12.9) years, of which 73% female. All outcomes showed significant improvements at each timepoint. At discharge, large effect sizes were found for disability, average and worst pain, fatigue and health-related quality of life. Improvements were largely sustained at 12-months. Relatively large proportions of patients had clinically relevant improvements after treatment (pain-related disability: 60%; average pain: 52%; worst pain: 37.4%; work capacity: 50%; concentration: 50%; fatigue: 46%). Patients who received a treatment extension showed further improvements for all outcome measures, except average pain.

CONCLUSIONS

At group level, all outcomes significantly improved with mainly large effect sizes. The results were mostly sustained. The proportion of patients showing clinically relevant improvements tends to be larger than previously reported for mixed CMP patients.

Prognostic subgroups of chronic pain patients using latent variable mixture modeling within a supervised machine learning framework

The present study combined a supervised machine learning framework with an unsupervised method, finite mixture modeling, to identify prognostically meaningful subgroups of diverse chronic pain patients undergoing interdisciplinary treatment. Questionnaire data collected at pre-treatment and 1-year follow up from 11,995 patients from the Swedish Quality Registry for Pain Rehabilitation were used. Indicators measuring pain characteristics, psychological aspects, and social functioning and general health status were used to form subgroups, and pain interference at follow-up was used for the selection and the performance evaluation of models. A nested cross-validation procedure was used for determining the number of classes (inner cross-validation) and the prediction accuracy of the selected model among unseen cases (outer cross-validation). A four-class solution was identified as the optimal model. Identified subgroups were separable on indicators, predictive of long-term outcomes, and related to background characteristics. Results are discussed in relation to previous clustering attempts of patients with diverse chronic pain conditions. Our analytical approach, as the first to combine mixture modeling with supervised, targeted learning, provides a promising framework that can be further extended and optimized for improving accurate prognosis in pain treatment and identifying clinically meaningful subgroups among chronic pain patients.

Interdisciplinary pain rehabilitation for immigrants with chronic pain who need language interpretation

OBJECTIVE

To investigate outcomes in patients with chronic pain after participation in an interdisciplinary pain rehabilitation programme with language interpreters, and to investigate the outcomes in women and men separately.

DESIGN

Prospective multi-centre cohort study.

PATIENTS

Ninety-five patients in Sweden with chronic pain who have insufficient knowledge of the Swedish language.

METHODS

Duration and intensity of pain, anxiety and depression, health-related quality of life and fear of movement were evaluated before and after the programme. Patients were compared with a reference group comprising Swedish-speaking patients participating in an ordinary interdisciplinary pain rehabilitation programme.

RESULTS

Before the interdisciplinary pain rehabilitation programme with language interpreters, all variables except pain duration differed significantly to the detriment of the studied group. The studied group showed significant improvements after the interdisciplinary pain rehabilitation programme with language interpreters, with regards to pain intensity, depression and fear of movement. The reference group improved significantly for all variables. The women in the studied group showed significant improvements for the same variables as the whole group, while the men in the studied group did not improve in any of the variables.

CONCLUSION

This study indicates that patients with chronic pain, and especially women, who have insufficient knowledge of Swedish seem to benefit from participating in an interdisciplinary pain rehabilitation programme with language interpreters. The result may be of value for the further development of rehabilitation programmes with language interpreters.

Interdisciplinary pain rehabilitation for patients with Ehlers-Danlos syndrome and hypermobility spectrum disorders

OBJECTIVE

Chronic pain is a common manifestation of Ehlers-Danlos syndrome and hypermobility spectrum disorders; thus it is often suggested that patients undergo generic interdisciplinary pain rehabilitation, despite there being little evidence to support this decision. The aim of this study is to examine the effectiveness of standard rehabilitation programmes for chronic pain on patients with Ehlers-Danlos syndrome and hypermobility spectrum disorders, compared with patients with other chronic pain disorders.

SUBJECTS

Data, collected between 2008 and 2016, were extracted from a Swedish national registry. The patient data comprised of 406 cases with Ehlers-Danlos syndrome or hypermobility spectrum disorders, 784 cases with a whiplash-related diagnosis, 3713 cases with diagnoses relating to spinal pain, and 2880 cases of fibromyalgia.

METHODS

The differences between groups on key outcome measures from pre- to 1-year follow-up after interdisciplinary pain rehabilitation were analysed using linear mixed effects models. Sensitivity analysis in the form of pattern-mixture modelling was conducted to discern the impact of missing data.

RESULTS

No significant differences were found in improvements from pre- to 1-year follow-up for patients with Ehlers-Danlos syndrome or hypermobility spectrum disorder compared with other diagnostic groups regarding measures of health-related quality of life, mental health, or fatigue. At follow-up, differences in pain interference (d = -0.34 (95% confidence interval [95% CI] -0.5 to -0.18)), average pain (d = 0.22 (95% CI 0.11-0.62)) and physical functioning (d = 2.19 (95% CI 1.61-2.77)) were detected for the group with spinal-related diagnoses in relation to those with EDS/HSD, largely due to pre-treatment group differences. Sensitivity analysis found little evidence for missing data influencing the results.

CONCLUSION

This study suggests that patients with Ehlers-Danlos syndrome/hypermobility spectrum disorders may benefit from inclusion in an interdisciplinary pain rehabilitation programme.

Pain and the biochemistry of fibromyalgia: patterns of peripheral cytokines and chemokines contribute to the differentiation between fibromyalgia and controls and are associated with pain, fat infiltration and content

Objectives

This explorative study analyses interrelationships between peripheral compounds in saliva, plasma, and muscles together with body composition variables in healthy subjects and in fibromyalgia patients (FM). There is a need to better understand the extent cytokines and chemokines are associated with body composition and which cytokines and chemokines differentiate FM from healthy controls.

Methods

Here, 32 female FM patients and 30 age-matched female healthy controls underwent a clinical examination that included blood sample, saliva samples, and pain threshold tests. In addition, the subjects completed a health questionnaire. From these blood and saliva samples, a panel of 68 mainly cytokines and chemokines were determined. Microdialysis of trapezius and erector spinae muscles, phosphorus-31 magnetic resonance spectroscopy of erector spinae muscle, and whole-body magnetic resonance imaging for determination of body composition (BC)-i.e., muscle volume, fat content and infiltration-were also performed.

Results

After standardizing BC measurements to remove the confounding effect of Body Mass Index, fat infiltration and content are generally increased, and fat-free muscle volume is decreased in FM. Mainly saliva proteins differentiated FM from controls. When including all investigated compounds and BC variables, fat infiltration and content variables were most important, followed by muscle compounds and cytokines and chemokines from saliva and plasma. Various plasma proteins correlated positively with pain intensity in FM and negatively with pain thresholds in all subjects taken together. A mix of increased plasma cytokines and chemokines correlated with an index covering fat infiltration and content in different tissues. When muscle compounds were included in the analysis, several of these were identified as the most important regressors, although many plasma and saliva proteins remained significant.

Discussion

Peripheral factors were important for group differentiation between FM and controls. In saliva (but not plasma), cytokines and chemokines were significantly associated with group membership as saliva compounds were increased in FM. The importance of peripheral factors for group differentiation increased when muscle compounds and body composition variables were also included. Plasma proteins were important for pain intensity and sensitivity. Cytokines and chemokines mainly from plasma were also significantly and positively associated with a fat infiltration and content index.

Conclusion

Our findings of associations between cytokines and chemokines and fat infiltration and content in different tissues confirm that inflammation and immune factors are secreted from adipose tissue. FM is clearly characterized by complex interactions between peripheral tissues and the peripheral and central nervous systems, including nociceptive, immune, and neuroendocrine processes.

Acceptance and Fear-Avoidance Mediate Outcomes of Interdisciplinary Pain Rehabilitation Programs at 12-Month Follow-Up: A Clinical Registry-Based Longitudinal Cohort Study from the Swedish Quality Registry for Pain Rehabilitation (SQRP)

Background

Factors that influence outcomes of interdisciplinary pain rehabilitation programs (IPRP) are poorly known. It is unclear how outcomes are influenced by pain intensity, psychological distress, and coping strategies.

Aim

This clinical registry-based longitudinal cohort study has three aims: 1) to determine the relative importance of pain intensity, psychological distress, acceptance, and fear-avoidance for changes in three outcomes of IPRP at 12-month follow-up; 2) to investigate whether the effects of pain intensity and psychological distress on the three outcomes are mediated via acceptance and fear-avoidance; and 3) to determine whether sex is a moderator.

Methods

This study uses Patient-Reported Outcome Measures (PROMs) from specialist units reporting data (2008-2016) to the Swedish Quality Registry for Pain Rehabilitation (SQRP). Adult chronic pain patients (N = 1991) answered the PROMs (background, pain, psychological distress, coping, participation, and health-related quality of life (HRQoL)). Partial Least Squares Structural Equation Modelling (PLS-SEM) was used to explore the aims.

Results

Changes in acceptance (β:0.424-0.553; all P<0.001) were the strongest predictor of the three outcomes (changes in life control, interference, and HRQoL) at 12-month follow-up. The next strongest predictor was baseline acceptance (β: 0.177-0.233; all P<0.001) and changes in fear-avoidance (β: -0.152- -0.186; all P<0.001). Baseline pain intensity and psychological distress showed weak positive associations. Their effects on the three outcomes were mediated via acceptance aspects. Sex was not a moderator.

Discussion and Conclusion

Acceptance aspects (baseline and changes) were important predictors of IPRP outcomes. Changes in fear-avoidance were also important although to a lesser degree. Some of the effects of pain intensity and psychological distress on outcomes were mediated via acceptance at baseline. Future PLS-SEM analysis of real-world IPRP should include more potential mediators (eg, catastrophizing and more facets of psychological flexibility and fear-avoidance) and the components of IPRP.

Neural mechanisms of priming effects of spicy food pictures induced analgesia

In this study, the effects of the priming of spicy food pictures on pain perception were evaluated in female participants using standardized methods of pain. Results from behavior tests revealed that the priming of spicy food pictures significantly reduced pain perception, particularly at high-pain intensities. Electrophysiological analysis showed that the analgesic effects of spicy food pictures were linked to decreased pain-related event-related potentials, such as N2 and P2 amplitudes, and suppressed θ-oscillations in the sensorimotor cortex. Both N2 amplitudes and θ-oscillations activities were found to be correlated with participants' pain perception. These results suggest that spicy-arousal stimuli may act as an "antagonist" to the increase in N2 amplitudes and θ-oscillations power induced by pain and influence the neuronal networks involved in integrating spontaneous nociceptive resources, which supports the dissociation theory of pain sensation and affection. These findings highlight the potential use of spicy-arousal stimuli as an analgesic and emphasize the importance of considering both the intensity of the stimuli and the individual's emotional state in the assessment and treatment of pain.

Effect on orofacial pain in patients with chronic pain participating in a multimodal rehabilitation programme - a pilot study

OBJECTIVES

Orofacial pain in patients taking part in a multimodal rehabilitation programme (MMRP) due to chronic bodily pain is common but it is not known whether such a rehabilitation programme can also have an effect on the presence of orofacial pain. The first aim of this study was to evaluate the effect of an MMRP on orofacial pain frequency. The second aim was to evaluate differences in the effect on quality of life and on psychosocial factors related to chronic pain.

METHODS

MMRP was evaluated through validated questionnaires from the Swedish Quality Registry for Pain Rehabilitation (SQRP). Fifty-nine patients participating in MMRP filled out the two screening questions for orofacial pain in addition to the SQRP questionnaires before and after participation in MMRP during the period August 2016 to March 2018.

RESULTS

Pain intensity decreased significantly after the MMRP (p=0.005). Fifty patients (69.4 %) reported orofacial pain before MMRP and no significant decrease after the programme (p=0.228). Among individuals with orofacial pain, the self-reported level of depression decreased after participation in the programme (p=0.004).

CONCLUSIONS

Even though orofacial pain is common among patients with chronic bodily pain, participation in a multimodal pain programme was not enough to reduce frequent orofacial pain. This finding implies that specific orofacial pain management including information about jaw physiology could be a justified component of patient assessment prior to a multimodal rehabilitation programme for chronic bodily pain.

Catastrophizing and acceptance are mediators between insomnia and pain intensity-an SQRP study of more than 6,400 patients with non-malignant chronic pain conditions

Background

Sleep problems (insomnia) and chronic pain are associated. Chronic pain and insomnia/insufficient sleep quality share similar symptoms and features. Although they have a bidirectional relationship, more research is needed to understand how they interact via mediators and how moderators influence this relationship.

Aims

In this large clinical registry-based cohort study (N = 6,497), we investigate important mediators between insomnia and pain intensity in a cross-sectional sample of chronic pain patients using advanced path analysis. In addition, we investigate whether some background variables were moderators of the identified important paths or not and the correlation patterns between insomnia and pain intensity in relation to the mediators.

Methods

This study includes a cohort of adult patients with chronic non-cancer pain from the Swedish Quality Registry for Pain Rehabilitation (SQRP) with data on patient-reported outcome measures (PROMs) (2008-2016). The PROMs cover the background, pain aspects, psychological distress, pain-related cognitions, activity/participation, and health-related quality of life variables of the patients. Partial least squares structural equation modeling was used to explore the direct and indirect (via mediators) relationships between insomnia and pain intensity at baseline.

Results

In this cohort study, insomnia was prevalent at 62.3%, and both direct and indirect mediating paths were present for the insomnia-pain intensity relationship. All of the mediating effects combined were weaker than the direct effect between insomnia and pain intensity. The mediating effects via catastrophizing and acceptance showed the strongest and equal mediating paths, and mediating effects via fear avoidance were the second strongest. Insomnia showed stronger direct significant correlations with psychological distress, catastrophizing, and acceptance compared with those of pain intensity. Sex, age, education level, spatial extent of pain, or body mass index did not moderate the mediating paths.

Discussion and conclusion

This study confirms the existence of significant direct and mediating paths between reported insomnia and pain intensity. Future studies should focus on illuminating how sleep interventions influence pain intensity and other important key factors that contribute to the distress of chronic pain patients.

Can Baseline Characteristics Predict Successful Outcomes after Individual, Physiotherapist-Led Rehabilitation in Patients with Chronic Musculoskeletal Pain?

Background

No strong and consistent variables to predict outcome after pain rehabilitation have been reported in patients with chronic musculoskeletal pain. The aim of the present study was to clarify if baseline variables could predict successful outcome after a unique, individualized, physiotherapist-led rehabilitation of nine sessions.

Methods

In 274 individuals with severe chronic musculoskeletal pain, the risk ratio (RR) and 95% confidence intervals (CIs) were estimated for potentially predictive baseline variables on successful outcomes of pain management, overall health, and pain rating.

Results

Statistically significant results show that patients rating moderate or severe baseline pain were in both cases 14% less likely to improve pain management compared to patients rating mild baseline pain (RR = 0.86; 95% CI 0.77-0.97, RR = 0.86; 95% CI 0.74-1.00). Patients with the shortest pain duration were 1.61 times more likely to improve overall health (RR = 1.61; 95% CI 1.13-2.29) compared to patients reporting the longest pain duration (>5 years). Patients reporting anxiety/depression or severe pain were in both cases 1.48 times more likely to improve overall health compared to better baseline presentations (RR = 1.48; 95% CI 1.16-1.88, RR = 1.48; 95% CI 1.03-2.15). Patients with regional/generalized pain were 36% less likely to rate pain reduction (RR = 0.64; 95% CI 0.41-1.00) compared to patients rating localized baseline pain. Of 17 potentially predictive baseline variables, four reached statistical significance for at least one of the three outcomes; although none of them for all three outcomes.

Conclusions

Of 17 potentially predictive baseline variables, mild pain ratings, short pain duration, and localized baseline pain were statistically significantly associated with improvements after individual, physiotherapist-led rehabilitation for patients with chronic musculoskeletal pain. This suggests that this type of rehabilitation probably should be offered early in the pain process. Reporting anxiety/depression or severe pain at the baseline did not hinder the improvements of overall health.

Change over time in functional capacity and self-perceived health status for patients with chronic musculoskeletal pain: a registry-based longitudinal study

BACKGROUND AND AIMS

Chronic musculoskeletal pain is a major public health problem worldwide. Both self-reported functional capacity and self-perceived health status are reduced in patients with chronic musculoskeletal pain. Previous studies mostly assessed functional capacity through self-reported questionnaires instead of objective measurements. The aim of this study, therefore, is to assess the amount of change over time and its clinical meaningfulness in functional capacity and self-perceived health status of patients with chronic musculoskeletal pain undergoing Bern Ambulatory Interprofessional Rehabilitation (BAI-Reha).

METHODS

The registry-based longitudinal cohort study with prospectively collected data from a rehabilitation programme took place in a real-life setting. Patients (n = 81) with chronic musculoskeletal pain took part in the BAI-Reha. The main outcomes were the six-minute-walk test (6MWT), the safe maximum floor-to-waist lift (SML) and the European Quality of Life and Health measure visual analogue scale (EQ VAS). Timepoints of measurement were at baseline and post-BAI-Reha (i.e., at 4 months). The quantity of interest was the adjusted time effect (point estimate, 95% confidence interval, and p-value for testing the null hypothesis of no change over time). Statistical significance (α = 0.05) and clinical meaningfulness of the mean value change over time were assessed using predefined thresholds (six-minute-walk test 50 m, SML 7 kg, and EQ VAS 10 points).

RESULTS

The linear mixed model analysis showed a statistically significant change over time for the six-minute-walk test (mean value change 56.08 m, 95% CI [36.13, 76.03]; p <0.001), SML (mean value change 3.92 kg, 95% CI [2.66, 5.19]; p <0.001), and EQ VAS (mean value change 9.58 points, 95% CI [4.87, 14.28]; p <0.001). Moreover, the improvement in the six-minute-walk test is clinically meaningful (mean value change 56.08 m) and almost clinically meaningful (mean value change 9.58 points) in the EQ VAS.

CONCLUSION

Patients walk further, lift more weight, and feel healthier after interprofessional rehabilitation when compared to baseline measurement. These findings confirm and add to previous results.

IMPLICATIONS

We encourage other providers of rehabilitation for patients with chronic musculoskeletal pain to measure functional capacity with objective outcome variables and to use self-reported outcome measures in addition to self-perceived health status. The well-established assessments used in this study are suitable for this purpose.

Machine learning clinical decision support for interdisciplinary multimodal chronic musculoskeletal pain treatment

Introduction

Chronic musculoskeletal pain is a prevalent condition impacting around 20% of people globally; resulting in patients living with pain, fatigue, restricted social and employment capacity, and reduced quality of life. Interdisciplinary multimodal pain treatment programs have been shown to provide positive outcomes by supporting patients modify their behavior and improve pain management through focusing attention on specific patient valued goals rather than fighting pain.

Methods

Given the complex nature of chronic pain there is no single clinical measure to assess outcomes from multimodal pain programs. Using Centre for Integral Rehabilitation data from 2019-2021 (n = 2,364), we developed a multidimensional machine learning framework of 13 outcome measures across 5 clinically relevant domains including activity/disability, pain, fatigue, coping and quality of life. Machine learning models for each endpoint were separately trained using the most important 30 of 55 demographic and baseline variables based on minimum redundancy maximum relevance feature selection. Five-fold cross validation identified best performing algorithms which were rerun on deidentified source data to verify prognostic accuracy.

Results

Individual algorithm performance ranged from 0.49 to 0.65 AUC reflecting characteristic outcome variation across patients, and unbalanced training data with high positive proportions of up to 86% for some measures. As expected, no single outcome provided a reliable indicator, however the complete set of algorithms established a stratified prognostic patient profile. Patient level validation achieved consistent prognostic assessment of outcomes for 75.3% of the study group (n = 1,953). Clinician review of a sample of predicted negative patients (n = 81) independently confirmed algorithm accuracy and suggests the prognostic profile is potentially valuable for patient selection and goal setting.

Discussion

These results indicate that although no single algorithm was individually conclusive, the complete stratified profile consistently identified patient outcomes. Our predictive profile provides promising positive contribution for clinicians and patients to assist with personalized assessment and goal setting, program engagement and improved patient outcomes.

Effects of interdisciplinary pain rehabilitation programs on neuropathic and non-neuropathic chronic pain conditions - a registry-based cohort study from Swedish Quality Registry for Pain Rehabilitation (SQRP)

BACKGROUND AND AIM

Neuropathic pain arises as a direct consequence of a lesion or disease affecting the somatosensory system. Pharmacological treatments for neuropathic pain often fail despite following guidelines. Interdisciplinary Pain Rehabilitation Programs (IPRP) are an effective intervention for chronic pain conditions. Little research has investigated whether IPRP can benefit patients with chronic neuropathic pain compared to other chronic pain conditions. This study assesses the real-world effects of IPRP on patients with chronic neuropathic pain compared to non-neuropathic patients using Patient-Reported Outcome Measures (PROMs) available in the Swedish Quality Registry for Pain Rehabilitation (SQRP).

METHODS

A neuropathic group of patients (n = 1,654) were identified in two steps. This group was compared to a non-neuropathic group (n = 14,355) composed of common diagnoses (low back pain, fibromyalgia, whiplash associated disorders, and Ehlers-Danlos Syndrome) in relation to background variables, three overall outcome variables, and mandatory outcome variables (pain intensity, psychological distress symptoms, activity/participation aspects and health-related quality of life variables). Of these patients 43-44% participated in IPRP.

RESULTS

At assessment, the neuropathic group reported significantly (with small effect sizes (ES)) more physician visits the previous year, older age, shorter pain durations, and less spatial extent of the pain (moderate ES). Moreover, for the 22 mandatory outcome variables, we found only clinically insignificant differences according to ESs between the groups. For patients participating in IPRP, the neuropathic group displayed equal or in some cases slightly superior results compared to the non-neuropathic group.

DISCUSSION AND CONCLUSION

After assessing the real-world effects of IPRP, this large study found that neuropathic pain patients can benefit from the IPRP intervention. Both registry studies and RCTs are needed to better understand which patients with neuropathic pain are most suitable for IPRP and to what extent special considerations need to be made for these patients within the framework of IPRP.

Fear network and pain extent: Interplays among psychological constructs related to the fear-avoidance model

OBJECTIVE

Psychological constructs related to the fear-avoidance model such as fear of movement, pain catastrophizing, and affective distress have been found to be inter-related among patients with chronic pain. However, relationships of these constructs have mostly been examined using regression-based analyses. This cross-sectional study employs a novel analytical approach, network analysis, to illustrate the complex interplays among these variables as well as pain intensity and pain interference.

METHODS

This study utilized the Swedish Quality Registry for Pain Rehabilitation, including data from 10,436 participants (76.0% women; M_age = 45.0 years). Networks were analyzed separately for patients with different pain extents (i.e., numbers of pain locations) as the interplays may differ qualitatively depending on pain extent.

RESULTS

We found that patients with a larger pain extent showed a worse clinical presentation (i.e., more depression and anxiety, increased fear of movement and pain interference), and their network differed from the patients with a smaller number of pain extent in terms of how strongly key variables were interconnected. In all network models, pain interference and catastrophizing showed consistently influential roles.

CONCLUSION

Our findings highlight the interactive nature of psychological aspects of pain and how interrelated associations differ depending on pain extent. Findings are discussed based on ideas on how both fear and pain become overgeneralized.

Interdisciplinary Multimodal Pain Rehabilitation in Patients with Chronic Musculoskeletal Pain in Primary Care-A Cohort Study from the Swedish Quality Registry for Pain Rehabilitation (SQRP)

Chronic pain is a major public health issue. Mounting evidence suggests that interdisciplinary multimodal pain rehabilitation programs (IMMRPs) performed in specialist pain care are an effective treatment for patients with chronic pain, but the effects of such treatment if performed in primary care settings have been less studied. The aims of this pragmatic study were to (1) describe characteristics of patients participating in IMMRPs in primary care; (2) examine whether IMMRPs in primary care improve pain, disability, quality of life, and sick leave 1-year post discharge in patients with chronic pain; and (3) investigate if outcomes differ between women and men. Data from 744 (645 women and 99 men, age range 18-65 years) patients with non-malignant chronic pain included in the Swedish Quality Registry for Pain Rehabilitation Primary Care were used to describe patient characteristics and changes in health and sick leave. At 1-year follow-up, the patients had improved significantly (p < 0.01) in all health outcome measures and had reduced sick leave except in men, where no significant change was shown in physical activity level. This study indicates that MMRPs in primary care improved pain and physical and emotional health and reduced sick leave, which was maintained at the 1-year follow-up.

Work Interventions Within Interdisciplinary Pain Rehabilitation Programs (IPRP) - Frequency, Patient Characteristics, and Association with Self-Rated Work Ability

Background

Interdisciplinary pain rehabilitation programs (IPRPs) help people with chronic pain improve their health and manage their work; however, the way IPRPs address sick leave could be improved. Although work interventions can be a part of IPRP, it is not well known how and to what extent.

Aim

This study explores the frequency of work interventions and the characteristics of patients who participate in work interventions as part of IPRP at specialist pain rehabilitation departments in Sweden. In addition, this study explores the association between participation in work interventions and change in patients' self-rated work ability after IPRP.

Methods

Data from the Swedish quality registry for pain rehabilitation (SQRP), which includes 3809 patients between 2016 and 2018, were analysed with descriptive statistics and regression analyses.

Results

The results indicate a high participation rate in work interventions (90%). Some differences were evident concerning characteristics of patients who participated in different work interventions. The return-to-work (RTW) plan, the most frequently used work intervention, had the strongest association with change in self-rated work ability after IPRP. However, the effect sizes were small, and the initial score best explained the change. Furthermore, there were differences between employed and unemployed patients and employment had a positive association with change in self-rated work ability.

Conclusion

More research is needed to understand IPRP's mechanisms and work interventions to support patients with chronic pain, reduce sick leave, and manage work. Employment status needs to be considered and interventions should be tailored to match the individual needs.

[Multiprofessional treatment approach in chronic back pain]

International guidelines recommend involving various professions and disciplines at an early stage in the event of chronic back pain. In connection with this, terms such as multiprofessional or interprofessional interventions are often mentioned without a uniform idea of what they mean. This article is intended to provide an overview of multiprofessional interventions for patients with chronic back pain and the integration into a meaningful interdisciplinary and interprofessional multimodal treatment concept. This is illustrated in a biopsychosocial pillar model, which should be pursued for each patient individually.

Pain intensity and psychological distress show different associations with interference and lack of life control: A clinical registry-based cohort study of >40,000 chronic pain patients from SQRP

Background

Both chronic pain and depressive and/or anxiety symptoms are associated with negative impacts on daily living, including interference and lack of life control. However, little is known about how pain and psychological distress affect these impacts.

Aim

The first aim was to assess how pain intensity, psychological distress, and social support interact with interference and lack of life control. A second aim was to investigate whether the strength of these relationships is moderated by the presence or absence of depression and/or anxiety.

Subjects and methods

Patient-Reported Outcome Measures (PROMs), which are available in the Swedish Quality Registry for Pain Rehabilitation (SQRP), were retrieved for patients with chronic pain (N = 40,184). A theoretical model with the constructs/latent variables pain intensity, psychological distress, interference, lack of life control, and social support was proposed and analyzed using Partial Least Squares Structural Equation Modelling (PLS-SEM). Indicators for these constructs were identified from the PROMs of the SQRP. Two models of the total cohort, which differed with respect to the causal relationship between pain intensity and psychological distress, were investigated. The moderating effects of anxiety and/or depression were also analyzed.

Results

Relatively low correlation and explanatory power (R ²= 0.16) were found for the pain intensity-psychological distress relationship. Pain intensity had a stronger effect on interference than on lack of life control. The reverse was found for psychological distress - i.e., psychological distress seemed to have a higher negative influence on function than on interference. The underlying assumption of the causal relationship between pain intensity and psychological distress determined how strong pain intensity and psychological distress influenced interference and lack of life control. Social support showed very similar absolute significant correlations with interference and lack of life control. Interference and lack of life control showed relatively weak associations. The psychological distress level was a moderating factor for several of the paths investigated.

Discussion and conclusion

A clinical treatment consequence of the low correlation between pain intensity and psychological distress may be that clinically treating one may not reduce the effect of the other. The relative importance of pain intensity and psychological distress on interference and lack of life control depends on the underlying assumption concerning the pain intensity-psychological distress relationship. Interference and lack of life control showed relatively weak associations, underscoring the need to clinically assess them separately. Social support influenced both impact constructs investigated. The cohort display heterogeneity and thus presence of definite signs of anxiety and/or depression or not was a moderating factor for several of the associations (paths) investigated. The results are important both for the assessments and the design of treatments for patients with chronic pain.

INTRODUCTION OF A MULTIMODAL PAIN REHABILITATION INTERVENTION IN PRIMARY CARE: A PILOT STUDY

Objective

To evaluate patient-reported outcome measures in patients with chronic musculoskeletal pain 1 year after participation in a case manager-led multimodal rehabilitation intervention in a Finnish primary care centre. Changes in healthcare utilization (HCU) were also explored.

Methods

A prospective pilot study with 36 participants. The intervention consisted of screening, multidisciplinary team assessment, a rehabilitation plan and case manager follow-up. Data were collected through questionnaires filled in after the team assessment and 1 year later. HCU data 1 year before and 1 year after team assessment were compared.

Results

At follow-up, satisfaction with vocational situation, self-reported work ability and health-related quality of life (HRQoL) had improved and pain intensity had diminished significantly for all participants. The participants who reduced their HCU improved their activity level and HRQoL. Early intervention by a psychologist and mental health nurse was distinctive for the participants who reduced HCU at follow-up.

Conclusion

The findings demonstrate the importance of early biopsychosocial management of patients with chronic pain in primary care. Identification of psychological risk factors at an early stage may lead to better psychosocial wellbeing, improve coping strategy and reduce HCU. A case manager may free up other resources and thereby contribute to cost savings.

The treatment lottery of chronic back pain? A case series at a multidisciplinary pain centre

OBJECTIVES

Despite the number of people affected by chronic back pain, and the many available treatment options, even the best modalities provide limited pain reduction on a group level, often without simultaneous improvements in functioning or health-related quality of life. The objective was to provide an overview of the treatment of chronic back pain in clinical practice at a multidisciplinary pain centre, and to study patient and pain characteristics in different treatment groups.

METHODS

104 chronic back pain patients (primary ICD-10-SE-diagnosis M53.0-M54.9 excluding M54.1 and M54.3), referred to the Pain and Rehabilitation Centre, University Hospital, Linköping in 2015, were studied using data from the Swedish Quality Registry for Pain Rehabilitation, self-reported medication data, and a retrospective medical record review.

RESULTS

The following treatment groups were identified: rehabilitation (n=21), analgesics (n=33), invasive intervention (n=14), and no treatment (n=35). Significant differences between groups were found with regards to age, sick leave, education level, persisting pain duration, punishing responses by significant other, previous invasive intervention, receiving sub-clinic, physician speciality and referring care level.

CONCLUSIONS

Overall, patient demographics were associated with treatment strategy to a higher degree than patient-reported outcome measures. Moreover, physician speciality and organisational factors seemed to play a role in treatment choice.

Long-term Use of Wearable Health Technology by Chronic Pain Patients

OBJECTIVES

People living with chronic pain may use wearable health technology (WHT) in conjunction with an expert-directed pain management program for up to 1 year. WHT use may be associated with improvements in key patient outcomes.

METHODS

A 12-month study of WHT use among people with chronic pain was conducted, consisting of iPhone and Apple Watch applications to measure movement, sleep, and self-reported pain. Clinical outcomes among 105 patients enrolled in a multidisciplinary pain program that included WHT use were compared with 146 patients in the same program but without WHT, and to 161 patients receiving medical pain management without WHT.

RESULTS

Participants used the WHT on average 143.0 (SD: 117.6) out of 365 days. Mixed-effects models revealed participants who used WHT had decreases in depression scores (-7.83, P <0.01) and prescribed morphine milligram equivalents (-21.55, P =0.04) over 1 year. Control groups also showed decreases in depression scores (-5.08, P =0.01; -5.68, P <0.01) and morphine milligram equivalents (-18.67, P =0.01; -10.99, ns). The estimated slope of change among the WHT was not statistically different than control groups.

DISCUSSION

Patients who used WHT as part of their pain management program demonstrated a willingness to do so for extended periods of time despite living with chronic pain and other comorbidities. Data trends suggest that WHT use may positively impact depression and prescribed medication. Additional research is warranted to investigate the potential of WHT to improve the negative consequences of chronic pain.

What factors predict outcome from an inpatient multidisciplinary chronic pain service? A prospective cohort study

Objective To identify baseline factors associated with outcomes from an inpatient multidisciplinary pain management program (PMP) located in a bicultural area of Aotearoa New Zealand. Methods A prospective cohort study was undertaken involving 164 people with chronic pain who attended the PMP. Demographic, clinical, and psychosocial measures were obtained at baseline, whereas clinical and psychosocial outcome measures were also obtained at program discharge and 3-month follow up (N  = 100). Multivariate analyses were used to determine baseline demographic variables that were associated with outcomes at discharge and follow up. Results Being male and working full-time were associated with poorer outcomes in select measures at discharge. At the 3-month follow up, Māori ethnicity, working full-time, being retired or unemployed, or having chronic widespread pain were associated with poorer outcomes for some measures, whereas those with rheumatoid arthritis had greater self-efficacy. Conclusions Sex, ethnicity, employment status, and patient condition impact clinical outcomes from the program and in the time from discharge to follow up. Program content and/or delivery should be altered to promote more equitable outcomes for all patients in the long term.

Swedish Chronic Pain Biobank: protocol for a multicentre registry and biomarker project

INTRODUCTION

About 20% of the adult population have chronic pain, often associated with psychological distress, sick leave and poor health. There are large variations in the clinical picture. A biopsychosocial approach is used in investigation and treatment. The concept of personalised medicine, that is, optimising medication types and dosages for individual patients based on biomarkers and other patient-related factors, has received increasing attention in different diseases but used less in chronic pain. This cooperative project from all Swedish University Hospitals will investigate whether there are changes in inflammation and metabolism patterns in saliva and blood in chronic pain patients and whether the changes correlate with clinical characteristics and rehabilitation outcomes.

METHODS AND ANALYSIS

Patients at multidisciplinary pain centres at University Hospitals in Sweden who have chosen to participate in the Swedish Quality Registry for Pain Rehabilitation and healthy sex-matched and age-matched individuals will be included in the study. Saliva and blood samples will be collected in addition to questionnaire data obtained from the register. From the samples, proteins, lipids, metabolites and micro-RNA will be analysed in relation to, for example, diagnosis, pain characteristics, psychological distress, body weight, pharmacological treatment and clinical rehabilitation results using advanced multivariate data analysis and bioinformatics.

ETHICS AND DISSEMINATION

The study is approved by the Swedish Ethical Review Authority (Dnr 2021-04929) and will be conducted in accordance with the declaration of Helsinki.The results will be published in open access scientific journals and in popular scientific relevant journals such as those from patient organisations. Data will be also presented in scientific meetings, meeting with healthcare organisations and disseminated in different lecturers at the clinics and universities.

Reported Outcomes in Interdisciplinary Pain Treatment: An Overview of Systematic Reviews and Meta-Analyses of Randomised Controlled Trials

Background

There is considerable diversity of outcome selections and methodologies for handling the multiple outcomes across all systematic reviews (SRs) of Interdisciplinary Pain Treatment (IPT) due to the complexity. This diversity presents difficulties for healthcare decision makers. Better recommendations about how to select outcomes in SRs (with or without meta-analysis) are needed to explicitly demonstrate the effectiveness of IPT.

Objective

This overview systematically collates the reported outcomes and measurements of IPT across published SRs and identifies the methodological characteristics. Additionally, we provide some suggestions on framing the selection of outcomes and on conducting SRs of IPT.

Methods

Three electronic databases (PubMed, Cochrane Library, and Epistemonikos) and the PROSPERO registry for ongoing SR were supplemented with hand-searching ending on 30 September 2021.

Results

We included 18 SRs with data on 49007 people from 356 primary randomised controlled trials (RCTs); eight were followed by meta-analysis and ten used narrative syntheses of data. For all the SRs, pain was the most common reported outcome (72%), followed by disability/functional status (61%) and working status (61%). Psychological well-being and quality of life were also reported in half of the included SR (50%). The core outcome domains according to VAPAIN, IMMPACT, and PROMIS were seldom met. The methodological quality varied from critically low to moderate according to AMSTAR2. The AMSTAR2 rating was negatively correlated to the number of outcome domains in PROMIS, and VAPAIN was positively correlated with IMMPACT and PROMIS, indicating the intercorrelations between the reported outcomes.

Conclusion

This systematic overview showed wide-ranging disparity in reported outcomes and applied outcome domains in SRs evaluating IPT interventions for chronic pain conditions. The intercorrelations between the reported outcomes should be appropriately handled in future research. Some approaches are discussed as well.

Fibromyalgia: Associations Between Fat Infiltration, Physical Capacity, and Clinical Variables

Background

Obesity is a risk factor for the development of fibromyalgia (FM) and generally most studies report increased Body Mass Index (BMI) in FM. Obesity in FM is associated with a worse clinical presentation. FM patients have low physical conditioning and obesity further exacerbates these aspects. Hitherto studies of FM have focused upon a surrogate for overall measure of fat content, ie, BMI. This study is motivated by that ectopic fat and adipose tissues are rarely investigated in FM including their relationships to physical capacity variables. Moreover, their relationships to clinical variables including are not known. Aims were to 1) compare body composition between FM and healthy controls and 2) investigate if significant associations exist between body composition and physical capacity aspects and important clinical variables.

Methods

FM patients (n = 32) and healthy controls (CON; n = 30) underwent a clinical examination that included pressure pain thresholds and physical tests. They completed a health questionnaire and participated in whole-body magnetic resonance imaging (MRI) to determine body composition aspects.

Results

Abdominal adipose tissues, muscle fat, and BMI were significantly higher in FM, whereas muscle volumes of quadriceps were smaller. Physical capacity variables correlated negatively with body composition variables in FM. Both body composition and physical capacity variables were significant regressors of group belonging; the physical capacity variables alone showed stronger relationships with group membership. A mix of body composition variables and physical capacity variables were significant regressors of pain intensity and impact in FM. Body composition variables were the strongest regressors of blood pressures, which were increased in FM.

Conclusion

Obesity has a negative influence on FM symptomatology and increases the risk for other serious conditions. Hence, obesity, dietary habits, and physical activity should be considered when developing clinical management plans for patients with FM.

Mediators of change in depressed mood following pain rehabilitation among participants with mild, moderate, or severe depressive symptoms

BACKGROUND

Prior research indicates that depression and chronic pain commonly co-exist and impact each other. Interdisciplinary pain rehabilitation programs (IPRPs) have been shown to lead to statistically and clinically significant improvements for patients who report both depressed mood and chronic pain, however there is a gap in the literature regarding the mechanisms by which these improvements occur.

METHODS

This two-site, distinct sample study (Study 1: N = 303, 10-week, individual format, ACT-based program; Study 2: N = 406, 3-week, group format, CBT-based program) evaluated mediators of treatment improvement in depressive symptoms among adult IPRP participants who reported elevated depressive symptoms at program admission and examined treatment mechanisms for depressive symptoms.

RESULTS

Self-reported pain self-efficacy and pain catastrophizing - particularly the helplessness domain - mediated the treatment-related change in depression among IPRP participants with elevated depressive symptoms across the two sites and samples. In one sample, full mediation was achieved while in the other sample, partial mediation was achieved. Participants in both samples showed improvement on all measures.

LIMITATIONS

This study relied on self-report measures of depressive severity and not clinical diagnosis. Results may not generalize to other populations of patients with chronic pain. There was no control condition in either study.

CONCLUSION

Increasing pain self-efficacy and decreasing a sense of helplessness are important treatment targets among IPRP participants who endorse symptoms of depression.

Unravelling dystonic pain; a mixed methods survey to explore the language of dystonic pain and impact on life

PURPOSE

Dystonia is a neurological disorder characterised by involuntary muscle contractions. Pain is the primary non-motor symptom, and limited studies have investigated how dystonic pain is experienced. This study aimed to investigate how people with isolated dystonia describe their pain and compare across subgroups of dystonia.

METHODS

Anonymous online survey via social media asking participants to describe their pain in their own words, complete the McGill Pain Questionnaire (MPQ), and answer demographic questions. Thematic analysis identified common themes and frequencies were calculated for demographic and MPQ data.

RESULTS

One-hundred and sixty-five respondents were included (mean age 51 years, 85% female). Thematic analysis identified four major themes "Physical sensations", "Temporal features", "Destruction", "Impact on life" with several sub-themes. The most chosen MPQ descriptor was "exhausting" followed by "tight," "sharp," "pulling," and "aching". The most common descriptors showed similar prevalence across subgroups of dystonia.

CONCLUSION

As no objective tests for pain exist, pain sufferers must use language to describe their pain experience. People with isolated dystonia used sensory words combined with metaphorical language to detail temporal features of pain, as well as destructive internal battles or feelings of external forces acting upon them, and the significant toll pain has on everyday life. Implications for rehabilitationPain is a common and debilitating non-motor symptom for people living with dystonia and should be discussed in a persons treatment plan.Pain sufferers use language to discuss their pain experience with others and report they don't feel well understood by others including health professionals.People with dystonic pain commonly described physical sensations, temporal features, destructive forces, and the impact on life caused by their pain.Findings suggest the experience of pain with dystonia is varied and better pain management options for people with dystonia are needed.

Internet-Delivered Cognitive Behavioral Therapy for Insomnia Comorbid With Chronic Pain: Randomized Controlled Trial

Background

Patients with chronic pain often experience insomnia symptoms. Pain initiates, maintains, and exacerbates insomnia symptoms, and vice versa, indicating a complex situation with an additional burden for these patients. Hence, the evaluation of insomnia-related interventions for patients with chronic pain is important.

Objective

This randomized controlled trial examined the effectiveness of internet-based cognitive behavioral therapy for insomnia (ICBT-i) for reducing insomnia severity and other sleep- and pain-related parameters in patients with chronic pain. Participants were recruited from the Swedish Quality Registry for Pain Rehabilitation.

Methods

We included 54 patients (mean age 49.3, SD 12.3 years) who were randomly assigned to the ICBT-i condition and 24 to an active control condition (applied relaxation). Both treatment conditions were delivered via the internet. The Insomnia Severity Index (ISI), a sleep diary, and a battery of anxiety, depression, and pain-related parameter measurements were assessed at baseline, after treatment, and at a 6-month follow-up (only ISI, anxiety, depression, and pain-related parameters). For the ISI and sleep diary, we also recorded weekly measurements during the 5-week treatment. Negative effects were also monitored and reported.

Results

Results showed a significant immediate interaction effect (time by treatment) on the ISI and other sleep parameters, namely, sleep efficiency, sleep onset latency, early morning awakenings, and wake time after sleep onset. Participants in the applied relaxation group reported no significant immediate improvements, but both groups exhibited a time effect for anxiety and depression at the 6-month follow-up. No significant improvements on pain-related parameters were found. At the 6-month follow-up, both the ICBT-i and applied relaxation groups had similar sleep parameters. For both treatment arms, increased stress was the most frequently reported negative effect.

Conclusions

In patients with chronic pain, brief ICBT-i leads to a more rapid decline in insomnia symptoms than does applied relaxation. As these results are unique, further research is needed to investigate the effect of ICBT-i on a larger sample size of people with chronic pain. Using both treatments might lead to an even better outcome in patients with comorbid insomnia and chronic pain.

Trial Registration

ClinicalTrials.gov NCT03425942; https://clinicaltrials.gov/ct2/show/NCT03425942

Development and external validation of a prediction model for patient-relevant outcomes in patients with chronic widespread pain and fibromyalgia

BACKGROUND

The objective of this study was to develop prediction models and explore the external validity of the models in a large sample of patients with chronic widespread pain (CWP) and fibromyalgia (FM).

METHODS

Patients with CWP and FM referred to rehabilitation services in Norway (n=986) self-reported data on potential predictors prior to entering rehabilitation, and self-reported outcomes at one-year follow-up. Logistic regression models of improvement, worsening and work status, and a linear regression model of health-related quality of life (HRQoL), were developed using lasso regression. Externally validated estimates of model performance were obtained from the validation set.

RESULTS

The number of participants in the development and the validation sets was 771 and 215 respectively; only participants with outcome data (n = 519-532 and 185, respectively) were included in the analyses. On average, HRQoL and work status changed little over one year. The prediction models included 10-11 predictors. Discrimination (AUC statistic) for prediction of outcome at follow-up was 0.71 for improvement, 0.67 for worsening, and 0.87 for working. The median absolute error of predictions of HRQoL was 0.36 (0.22-0.51). Reasonably good predictions of working at follow-up and HRQoL could be obtained using only the baseline scores as predictors.

CONCLUSIONS

Moderately complex predictions models (10-11 predictors) generated poor to excellent predictions of patient-relevant outcomes. Simple prediction models of working and HRQoL at follow-up may be nearly as accurate and more practical.

Investigating the Long-Term Effect of an Interdisciplinary Multimodal Rehabilitation Program on Levels of Bioactive Lipids and Telomerase Activity in Blood from Patients with Chronic Pain

Mechanism-based diagnosis and therapies for chronic pain are lacking. However, bio-psycho-social interventions such as interdisciplinary multimodal rehabilitation programs (IPRPs) have shown to be relatively effective treatments. In this context we aim to investigate the effects of IPRP on the changes in levels of bioactive lipids and telomerase activity in plasma, and if these changes are associated with changes in pain intensity and psychological distress. This exploratory study involves 18 patients with complex chronic pain participating in an IPRP. Self-reports of pain, psychological distress, physical activity, and blood samples were collected before the IPRP and at a six-month follow-up. Levels of arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG), palmitoylethanolamide (PEA), oleoylethanolamide (OEA), stearoylethanolamide (SEA), and telomerase activity were measured. Pain intensity was decreased, and SEA levels were increased at the six-month follow up. A significant correlation existed between changes in SEA levels and pain intensity. AEA levels, were inversely correlated with physical activity. Furthermore, 2-AG and telomerase activity was significantly correlated at the six-month follow-up. This study confirms that IPRP is relatively effective for reduction in chronic pain. Changes in SEA were correlated with changes in pain intensity, which might indicate that SEA changes reflect the pain reduction effects of IPRP.

Internet-Delivered Acceptance and Commitment Therapy Added to Multimodal Pain Rehabilitation: A Cluster Randomized Controlled Trial

Internet-delivered interventions hold the possibility to make pain rehabilitation more accessible and adaptable by providing qualified individualized psychological care to chronic pain patients in their homes. Acceptance and commitment therapy (ACT) has shown promising results on psychological functioning and pain acceptance. Internet-delivered ACT (IACT) added to multimodal pain rehabilitation program (MMRP) in primary care has, so far, not shown better results than MMRP alone. The aim of this cluster randomized controlled study was to investigate the effects of adding IACT during and after MMRP in specialist care on psychological outcomes. In total, 122 patients who enrolled in a specialist pain clinic were cluster randomized groupwise to either MMRP (n = 12 groups) or to MMRP with added IACT (n = 12 groups). The IACT addition included 6 weeks of treatment during MMRP and 11 weeks of aftercare following MMRP. Online and paper-and-pencil self-report measures of pain acceptance, psychological inflexibility, self-efficacy, and psychosocial consequences of pain, were collected at four occasions: prior to and post MMRP, post aftercare intervention and at 1 year follow-up. Dropout was extensive with 25% dropping out at post treatment, an additional 35% at post aftercare, and 29% at 1 year follow-up. Medium treatment between-group effects were found on pain acceptance in favor of the group who received IACT added to MMRP, at post treatment and at post aftercare. Large effects were seen on psychological inflexibility and self-efficacy at post aftercare. A medium effect size was seen on affective distress at post aftercare. Moreover, a medium effect on self-efficacy was found at 1 year follow-up. The results indicate that IACT added during MMRP may enhance the treatment effects on pain-related psychological outcomes. Results also suggest that IACT as aftercare may strengthen the long-term effect of MMRP. However, adding a second pain treatment, IACT, to an already extensive pain treatment, MMRP, could be perceived as too comprehensive and might hence influence completion negatively. Further research on adverse events and negative effects could be helpful to improve adherence. Next step of implementation trials could focus on adding IACT before MMRP to improve psychological functioning and after MMRP to prolong its effect.

Pain Rehabilitation's Effect on People in Chronic Pain: A Prospective Cohort Study

Multidisciplinary long-term pain rehabilitation programs with a team of healthcare professionals are an integrated approach to treat patients with chronic non-malignant pain. In this longitudinal prospective cohort study, we investigated the long-term effects of multidisciplinary pain rehabilitation on the self-reported causes of pain, pain self-management strategies, sleep, pain severity, and pain’s interference with life, pre- and post-treatment. Eighty-one patients, aged 20–69 years, with chronic pain responded. The two most frequently reported perceived causes of pain were fibromyalgia and accidents. The difference in average self-reported pain severity decreased significantly at one-year follow-up (p < 0.001), as did pain’s interference with general activities, mood, walking ability, sleep, and enjoyment of life. At one-year follow-up, participants (21%) rated their health as good/very good and were more likely to state that it was better than a year before (20%). No change was found in the use of pain self-management strategies such as physical training at one-year follow-up. The intervention was effective for the participants, as reflected in the decreased pain severity and pain interference with life.

Pain, Sleep, and Health-Related Quality of Life after Multidisciplinary Intervention for Chronic Pain

Multidisciplinary pain-management programs have the potential to decrease pain intensity, improve health-related quality of life (HRQOL), and increase sleep quality. In this longitudinal prospective cohort study, the aim was to investigate the long-term effects of multidisciplinary pain rehabilitation interventions in Iceland. More precisely, we (a) explored and described how individuals with chronic pain evaluated their pain severity, sleep, and HRQOL at pre-treatment and at one-year follow-up and (b) examined what predicted the participants' one-year follow-up HRQOL. Seventy-nine patients aged 20-68 years, most of whom were women (85%), responded. The participants scored their pain lower at one-year follow-up (p < 0.001). According to their response, most of them had disrupted sleep, mainly because of pain. One year after the treatment, more participants slept through the night (p = 0.004), and their HRQOL increased. Higher pre-treatment mental component summary (MCS) scores and having pursued higher education predicted higher MCS scores at one-year follow-up, and higher pre-treatment physical component summary (PCS) scores predicted higher PCS scores at one-year follow-up. Sleep problems, being a woman, and having children younger than 18 years of age predicted lower MCS scores at one-year follow-up. These findings are suggestive that patients should be examined with respect to their mental status, and it could be beneficial if they received some professional support after completing the intervention.

A Network Analysis of Clinical Variables in Chronic Pain: A Study from the Swedish Quality Registry for Pain Rehabilitation (SQRP)

BACKGROUND

Efforts to identify specific variables that impact most on outcomes from interdisciplinary pain rehabilitation are challenged by the complexity of chronic pain. Methods to manage this complexity are needed. The purpose of the study was to determine the network structure entailed in a set of self-reported variables, examine change, and look at potential predictors of outcome, from a network perspective.

METHODS

In this study we apply network analysis to a large sample of people seeking interdisciplinary pain treatment (N = 2,241). Variables analyzed include pain intensity, pain interference, extent of pain, depression, anxiety, insomnia, and psychological variables from cognitive behavioral models of chronic pain.

RESULTS

We found that Acceptance, Pain Interference, and Depression were key, "central," variables in the pretreatment network. Interestingly, there were few changes in the overall network configuration following treatment, specifically with respect to which variables appear most central relative to each other. On the other hand, Catastrophizing, Depression, Anxiety, and Pain Interference each became less central over time. Changes in Life Control, Acceptance, and Anxiety were most strongly related to changes in the remainder of the network as a whole. Finally, no network differences were found between treatment responders and non-responders.

CONCLUSIONS

This study highlights potential future targets for pain treatment. Further application of a network approach to interdisciplinary pain rehabilitation data is recommended. Going forward, it may be better to next do this in a more comprehensive theoretically guided fashion, and ideographically, to detect unique individual differences in potential treatment processes.

Lose Pain, Lose Weight, and Lose Both: A Cohort Study of Patients with Chronic Pain and Obesity Using a National Quality Registry

Background

It is known that chronic pain makes it difficult to lose weight, but it is unknown whether obese patients (body mass index ≥30 kg/m²) who experience significant pain relief after interdisciplinary multimodal pain rehabilitation (IMMPR) lose weight.

Objective

This study investigated whether obese patients with chronic pain lost weight after completing IMMPR in specialist pain units. The association of pain relief and weight change over time was also examined.

Methods

Data from obese patients included in the Swedish Quality Registry for Pain Rehabilitation for specialized pain units were used (N=224), including baseline and 12-month follow-up after IMMPR from 2016 to 2018. Patients reported body weight and height, pain aspects (eg, pain intensity), physical activity behaviours, psychological distress, and health-related quality of life (HRQoL). A reduction of at least 5% of initial weight indicates clinically significant weight loss. Patients were classified into three groups based on the pain relief levels after IMMPR: pain relief of clinical significance (30% or more reduction of pain intensity); pain relief without clinical significance (less than 30% reduction of pain intensity); and no pain relief. Linear mixed regression models were used to examine the weight changes among the groups with different pain relief levels.

Results

A significant reduction of pain intensity was found after IMMPR (p < 0.01, effect size Cohen’s d = 0.34). A similar proportion of patients in the three groups with different pain relief levels had clinically significant weight loss (20.2%~24.3%, p = 0.47). Significant improvements were reported regarding physical activity behaviour, psychological distress, and HRQoL, but weight change was not associated with changes of pain intensity.

Conclusion

About one-fifth of obese patients achieved significant weight reduction after IMMPR. Obese patients need a tailored pain rehabilitation program incorporating a targeted approach for weight management.

[Effectiveness of an individualized multimodal treatment of chronic pain patients : A retrospective real-life analysis with 3-year follow-up]

BACKGROUND

Chronic pain is a worldwide problem of healthcare along with social and economic factors. The Center for Pain Medicine (CPM) Nottwil offers individualized, interdisciplinary, multimodal pain rehabilitation based on the biopsychosocial approach. The aim of this study was to obtain a real-life analysis of chronic pain patients who were treated at the CPM Nottwil, to understand how they were treated and to analyze the long-term effects of the treatment.

METHODS

In a retrospective cohort study data of all patients who underwent a first medical examination at the CPM Nottwil in 2011 were included in the study. The effectiveness of the treatment was analyzed in a 3-year follow-up measurement. The main outcome was the general well-being of the patient.

RESULTS

In 2011, 628 chronic pain patients underwent a first medical examination at the CPM Nottwil. They showed low values in the dimension of general well-being and a high impairment due to severely limiting pain intensity. Although the power analysis suggested a sample size of 170 patients for the follow-up measurement, only 46 participants (responders) were included in the final analysis. Baseline characteristics between responders and non-responders of the follow-up-group showed statistically significant differences for health-related quality of life (SF-12) and the anxiety and depression scale (HADS), but not for other sample characteristics. Improvement from pretreatment to follow-up emerged in the dimension of well-being, physical well-being and pain intensity. At follow-up 30% reported being pain-free.

CONCLUSION

Individualized, interdisciplinary, multimodal and mostly outpatient pain programs are an effective treatment for patients suffering from chronic pain in the long term. For the first time this effect has been proven in a clinically representative cohort. Limitations of this study are low response rates in the follow-up group and differences in baseline characteristics (anxiety, depression and quality of life) between responders and non-responders.

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

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.

Spreading of Pain in Patients with Chronic Pain is Related to Pain Duration and Clinical Presentation and Weakly Associated with Outcomes of Interdisciplinary Pain Rehabilitation: A Cohort Study from the Swedish Quality Registry for Pain Rehabilitation (SQRP)

Introduction

The extent to which pain is distributed across the body (spreading of pain) differs largely among patients with chronic pain conditions and widespread pain has been linked to poor quality of life and work disability. A longer duration of pain is expected to be associated with more widespread pain, but studies are surprisingly scarce. Whether spreading of pain is associated with clinical presentation and treatment outcome in patients seen in interdisciplinary multimodal pain rehabilitation programs (IMMRPs) is unclear. The association between spreading of pain and (1) pain duration (2) clinical presentation (eg, pain intensity, pain-related cognitions, psychological distress, activity/participation aspects and quality of life) and (3) treatment outcome were examined.

Methods

Data from patients included in the Swedish Quality Registry for Pain Rehabilitation were used (n=39,916). A subset of patients that participated in IMMRPs (n=14,666) was used to examine whether spreading of pain at baseline predicted treatment outcome. Spreading of pain was registered using 36 predefined anatomical areas which were summarized and divided into four categories: 1–6 regions with pain (20.6% of patients), 7–12 regions (26.8%), 13–18 regions (22.0%) and 19–36 regions (30.6%).

Results

More widespread pain was associated with a longer pain duration and a more severe clinical picture at baseline with the strongest associations emerging in relation to health and pain aspects (pain intensity, pain interference and pain duration). Widespread pain was associated with a poorer overall treatment outcome following IMMRPs at both posttreatment and at a 12-month follow-up, but effect sizes were small.

Discussion

Spreading of pain is an indicator of the duration and severity of chronic pain and to a limited extent to outcomes of IMMRP. Longer pain duration in those with more widespread pain supports the concept of early intervention as clinically important and implies a need to develop and improve rehabilitation for patients with chronic widespread pain.

Evidence of Mitochondrial Dysfunction in Fibromyalgia: Deviating Muscle Energy Metabolism Detected Using Microdialysis and Magnetic Resonance

In fibromyalgia (FM) muscle metabolism, studies are sparse and conflicting associations have been found between muscle metabolism and pain aspects. This study compared alterations in metabolic substances and blood flow in erector spinae and trapezius of FM patients and healthy controls. FM patients (n = 33) and healthy controls (n = 31) underwent a clinical examination that included pressure pain thresholds and physical tests, completion of a health questionnaire, participation in microdialysis investigations of the etrapezius and erector spinae muscles, and also underwent phosphorus-31 magnetic resonance spectroscopy of the erector spinae muscle. At the baseline, FM had significantly higher levels of pyruvate in both muscles. Significantly lower concentrations of phosphocreatine (PCr) and nucleotide triphosphate (mainly adenosine triphosphate) in erector spinae were found in FM. Blood flow in erector spinae was significantly lower in FM. Significant associations between metabolic variables and pain aspects (pain intensity and pressure pain threshold PPT) were found in FM. Our results suggest that FM has mitochondrial dysfunction, although it is unclear whether inactivity, obesity, aging, and pain are causes of, the results of, or coincidental to the mitochondrial dysfunction. The significant regressions of pain intensity and PPT in FM agree with other studies reporting associations between peripheral biological factors and pain aspects.

Facing obesity in pain rehabilitation clinics: Profiles of physical activity in patients with chronic pain and obesity-A study from the Swedish Quality Registry for Pain Rehabilitation (SQRP)

Background

The obesity epidemic has influenced pain rehabilitation clinics. To date, little is known about baseline level of physical activity (PA) in patients referred to pain rehabilitation clinics. We aimed to investigate the PA levels of patients referred to pain rehabilitation clinics and to evaluate the effect of excess weight on PA level.

Methods and findings

Data were obtained from the Swedish Quality Registry for Pain Rehabilitation between 2016 and 2017. These data included PA time (everyday PA and physical exercise per week), Body Mass Index (BMI), sociodemographic factors, chronic pain and psychological aspects (e.g., pain intensity, depressive and anxiety symptoms and insomnia problems). Insufficient PA was defined as less than 150 minutes per week. We performed logistic regressions as well as orthogonal partial least square regression to estimate the effects of excess weight on PA. Over one-fourth of the patients were classified as obese (BMI ≥30 kg/m², 871/3110, 25.3%) and nearly one-third of these patients were classified as severely obese (BMI ≥35 kg/m², 242/871, 27.8%). Time estimations for physical exercise varied among the BMI groups, but patients in the higher BMI category were more likely to spend less time on everyday PA. Compared to normal weight, mild obesity [odds ratio (OR) 0.65, 95% confidence interval (CI) 0.53–0.81] and severe obesity (OR 0.56, 95% CI 0.42–0.74) were associated with less PA. Mild obese patients had an elevated risk of 65% and severe obese patients had an elevated risk of 96% for insufficient PA. Increased pain intensity was positively related to insufficient PA (OR 1.17, 95% CI 1.06–1.29) among the obese patients.

Conclusion

Having low PA is very common for patients referred to pain rehabilitation clinics, especially for those with comorbid obesity. As a first step to increase PA, obese patients need to be encouraged to increase the intensity and amount of less painful daily PA.

What Is the Effectiveness of Different Duration Interdisciplinary Treatment Programs in Patients with Chronic Pain? A Large-Scale Longitudinal Register Study

Chronic pain is a leading cause of disability globally. Interdisciplinary multimodal pain rehabilitation (IMPR) targets pain with a bio-psycho-social approach, often delivered as composite programs. However, evidence of optimal program duration for the rehabilitation to succeed remains scarce. This study evaluated the effectiveness of different duration IMPR-programs-using within- and between-effects analyses in a pragmatic multicenter register-based controlled design. Using the Swedish Quality Registry for Pain Rehabilitation, data from fifteen clinics specialized in chronic pain rehabilitation across Sweden were retrieved. Participants were patients with chronic musculoskeletal pain who had taken part in short (4-9 weeks; n = 924), moderate (10 weeks; n = 1379), or long (11-18 weeks; n = 395) IMPR programs. Longitudinal patient-reported outcome data were assessed at baseline, post-intervention, and at a 12-month follow-up. Primary outcomes were health-related quality of life, presented as perceived physical and mental health (SF-36). Secondary outcomes included the Hospital Anxiety and Depression Scale (HADS), pain intensity (NRS 0-10), the Multidimensional Pain Inventory (MPI), and perceived health (EQ-5D). Overall, all groups showed improvements. No clinically important effect emerged for different duration IMPR. In conclusion, while our results showed that patients following IMPR report improvement across a bio-psycho-social specter, a longer program duration was no more effective than a shorter one.

Influences of Sex, Education, and Country of Birth on Clinical Presentations and Overall Outcomes of Interdisciplinary Pain Rehabilitation in Chronic Pain Patients: A Cohort Study from the Swedish Quality Registry for Pain Rehabilitation (SQRP)

This study investigates the effects of sex, education, and country of birth on clinical presentations and outcomes of interdisciplinary multimodal pain rehabilitation programs (IMMRPs). A multivariate improvement score (MIS) and two retrospective estimations of changes in pain and ability to handle life situations were used as the three overall outcomes of IMMRPs. The study population consisted of chronic pain patients within specialist care in the Swedish Quality Registry for Pain Rehabilitation (SQRP) between 2008 and 2016 at baseline (n = 39,916), and for the subset participating in IMMRPs (n = 14,666). A cluster analysis based on sex, education, and country of origin revealed significant differences in the following aspects: best baseline clinical situation was for European women with university educations and the worst baseline clinical situation was for all patients born outside Europe of both sexes and different educations (i.e., moderate-large effect sizes). In addition, European women with university educations also had the most favorable overall outcomes in response to IMMRPs (small effect sizes). These results raise important questions concerning fairness and equality and need to be considered when optimizing assessments and content and delivery of IMMRPs for patients with chronic pain.

Plasma protein patterns are strongly correlated with pressure pain thresholds in women with chronic widespread pain and in healthy controls-an exploratory case-control study

Chronic widespread pain (CWP) is a complex pain condition characterized by generalized musculoskeletal pain and often associated with other symptoms. An important clinical feature is widespread increased pain sensitivity such as lowered pain thresholds for mechanical stimuli (pressure pain thresholds [PPT]). There is a growing interest in investigating the activated neurobiological mechanisms in CWP, which includes fibromyalgia. In CWP, strong significant correlations have been found between muscle protein patterns and PPT. This explorative proteomic study investigates the multivariate correlation pattern between plasma proteins and PPT in CWP and in healthy controls (CON). In addition, this study analyses whether the important proteins for PPT differ between the 2 groups.Using 2-dimensional gel electrophoresis, we analyzed the plasma proteome of the CWP (n = 15) and the CON (n = 23) and proteins were identified using mass spectrometry. For both the CWP and the CON, the associations between the identified proteins and PPT were analyzed using orthogonal partial least square in 2 steps.Significant associations between certain plasma proteins and PPT existed both in CWP (R = 0.95; P = .006) and in CON (R = 0.89; P < .001). For both groups of subjects, we found several proteins involved in PPT that reflect different biological processes. The plasma proteins as well as the biological processes involved in PPT differed markedly between the 2 groups of subjects.This study suggests that plasma protein patterns are associated with pain thresholds in CWP. Using the plasma proteome profile of CWP to study potential biomarker candidates could provide a snapshot of ongoing systemic mechanisms in CWP.

Reported Outcomes in Published Systematic Reviews of Interdisciplinary Pain Treatment: Protocol for a Systematic Overview

BACKGROUND

Interdisciplinary pain treatment (IPT) is a complex intervention; its outcomes are very diverse, as are the methodologies for handling those outcomes. This diversity may hamper evidence-based decision making. Presently, there is no gold standard recommendation of how to select reported outcomes in published systematic reviews and meta-analyses to explicitly demonstrate the effectiveness of IPT.

OBJECTIVE

In this systematic overview, we aim to evaluate the reported outcome domains and measurements across published systematic reviews and meta-analyses and to identify any methods, considerations, and discussion regarding the handling of the chosen outcome domains and measurements.

METHODS

This article describes the protocol for a systematic overview of the outcomes reported in published systematic reviews and meta-analyses of randomized control trials for the effectiveness of IPT versus any control. To this end, we searched the PubMed, Cochrane Library, and Epistemonikos databases from inception to December 2019. Two independent investigators screened the titles, the abstracts of the identified records, and the full texts of the potentially eligible systematic reviews and meta-analyses, performed data extraction according to predefined forms, and rated the quality of the included systematic reviews and meta-analyses. The quality of the included systematic reviews and meta-analyses will be rated with AMSTAR (A MeaSurement Tool to Assess systematic Reviews) 2. Data will be analyzed descriptively and stratified by AMSTAR 2.

RESULTS

We introduced the rationale and design of a systematic overview to summarize and map the chosen IPT outcome domains and the methods of handling these outcomes reported in published systematic reviews and meta-analyses. As of December 2019, we collected 5229 systematic reviews, of which 147 (2.81%) were examined in-depth for eligibility. Topline results are anticipated by September 2020.

CONCLUSIONS

The results of this study will be published as soon as they are available. Our results will fill a gap in the related literature and will be used to inform the development of a set of recommendations that can be applied in systematic reviews and hopefully serve as a gold standard.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/17795.

A Step Towards a Better Understanding of Pain Phenotypes: Latent Class Analysis in Chronic Pain Patients Receiving Multimodal Inpatient Treatment

Purpose

The number of non-responders to treatment among patients with chronic pain (CP) is high, although intensive multimodal treatment is broadly accessible. One reason is the large variability in manifestations of CP. To facilitate the development of tailored treatment approaches, phenotypes of CP must be identified. In this study, we aim to identify subgroups in patients with CP based on several aspects of self-reported health.

Patients and Methods

A latent class analysis (LCA) was carried out in retrospective data from 411 patients with CP of different origins. All patients experienced severe physical and psychosocial consequences and were therefore undergoing multimodal inpatient pain treatment. Self-reported measures of pain (visual analogue scales for pain intensity, frequency, and impairment; Pain Perception Scale), emotional distress (Patient Health Questionnaire, PHQ-9; Generalized Anxiety Disorder Scale, GAD-7) and physical health (Short Form Health Survey; SF-8) were collected immediately after admission and before discharge. Instruments assessed at admission were used as input to the LCA. Resulting classes were compared in terms of patient characteristics and treatment outcome.

Results

A model with four latent classes demonstrated the best model fit and interpretability. Classes 1 to 4 included patients with high (54.7%), extreme (17.0%), moderate (15.6%), and low (12.7%) pain burden, respectively. Patients in class 4 showed high levels of emotional distress, whereas emotional distress in the other classes corresponded to the levels of pain burden. While pain as well as physical and mental health improved in class 1, only the levels of depression and anxiety improved in patients in the other groups during multimodal treatment.

Conclusion

The specific needs of these subgroups should be taken into account when developing individualized treatment programs. However, the retrospective design limits the significance of the results and replication in prospective studies is desirable.