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 (ß: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 (ß: 0.177-0.233; all P<0.001) and changes in fear-avoidance (ß: -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.

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.

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.

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.

Burden of disease and management of osteoarthritis and chronic low back pain: healthcare utilization and sick leave in Sweden, Norway, Finland and Denmark (BISCUITS): study design and patient characteristics of a real world data study.

OBJECTIVES: Osteoarthritis (OA) and chronic low back pain (CLBP) are common musculoskeletal disorders with substantial patient and societal burden. Nordic administrative registers offer a unique opportunity to study the impact of these conditions in the real-world setting. The Burden of Disease and Management of Osteoarthritis and Chronic Low Back Pain: Health Care Utilization and Sick Leave in Sweden, Norway, Finland and Denmark (BISCUITS) study was designed to study disease prevalence and the societal and economic burden in broad OA and CLBP populations. METHODS: Patients in Sweden, Norway, Finland and Denmark with diagnoses of OA or CLBP (low back pain record plus ≥2 pain relief prescriptions to indicate chronicity) were identified in specialty care, in primary care (Sweden and Finland) and in a quality-of-care register (Sweden). Matched controls were identified for the specialty care cohort. Longitudinal data were extracted on prevalence, treatment patterns, patient-reported outcomes, social and economic burden. RESULTS: Almost 1.4 million patients with OA and 0.4 million with CLBP were identified in specialty care, corresponding to a prevalence in the Nordic countries of 6.3 and 1.9%, respectively. The prevalence increased to 11-14% for OA and almost 6% for CLBP when adding patients identified in primary care. OA patients had a higher Elixhauser comorbidity index (0.66 vs. 0.46) and were using opioids (44.7 vs. 10.2%) or long-term nonsteroidal anti-inflammatory drug (NSAIDs) (20.9 vs. 4.5%) more than four times as often as compared to controls. The differences were even larger for CLBP patients compared to their controls (comorbidity index 0.89 vs. 0.39, opioid use 77.7 vs. 9.4%, and long-term NSAID use 37.2 vs. 4.8%). CONCLUSIONS: The BISCUITS study offers an unprecedented, longitudinal healthcare data source to quantify the real-world burden of more than 1.8 million patients with OA or CLBP across four countries. In subsequent papers we aim to explore among others additional outcomes and subgroups of patients, primarily those patients who may benefit most from better healthcare management.

Physiotherapist-led rehabilitation for patients with chronic musculoskeletal pain: interventions and promising long-term outcomes.

BACKGROUND: There is no consensus on best content, set-up, category of involved healthcare professionals or duration of rehabilitation-programs for patients with chronic musculoskeletal pain, and outcomes show varying results. Individual care regimes for sub-groups of patients have been proposed. AIM: To describe the type of interventions used in a physiotherapist-led, rehabilitation-program for patients with chronic musculoskeletal pain, refractory to preceding treatments. A second aim was to report clinical outcomes at 1-year follow-up after the intervention period. METHODS: All patients referred to physiotherapist within a specialist pain-unit due to being refractory to preceding treatments, and deemed fit to undergo physiotherapy-based, individualized rehabilitation during 2014-2018 were consecutively included and followed-up 1 year after ending the program. The inclusion was based on structured 'clinical reasoning' using the referral, examination and on patient-relevant outcome measures. The individual interventions, recorded according to a manual used when reading the patients' medical records, were described. Primary outcomes were clinical results of perceived pain, disability and overall health at start, discharge and 1 year after discharge. RESULTS: In total, 274 patients (mean age 42 years, 71% women) were included, suffering from chronic, severe, musculoskeletal pain (VAS median 7/10, duration median 2.8 years) and moderate disability. The most frequent interventions were education, sensorimotor training, physical activity-advice and interventions for structures/functions (for example manual techniques, stretching) for a median of nine sessions during five months. Despite refractory to preceding treatments, 45% of the patients rated clinically important improvements on pain, 61% on disability and 50% on overall health at discharge and the figures were similar at 1-year follow-up. CONCLUSIONS: A physiotherapist-led, one-to-one, rehabilitation-program of median nine sessions during five months, combining individualized education, sensorimotor training, physical activity-advice and interventions for structures/functions rendered clinically relevant improvements on pain, disability and overall health in half of the patients at 1-year follow-up. Since the cohort consisted of patients refractory to preceding treatments, we believe that these results warrant further studies to identify the subgroups of patients with chronic musculoskeletal pain that will improve from new, distinctive, resource-effective rehabilitation-programs involving individualized rehabilitation.

[Pain rehabilitation starts with a pain analysis]. / Långvarig smärta kräver teambaserad rehabilitering.

Pain rehabilitation is a process starting with a pain analysis to find an adequate pain diagnosis, a classification based on pain mechanisms and a mapping of the psychological and social situation of the patient. These factors are the basis for the treatment plan. Monodisciplinary treatments such as pharmacological treatments, physiotherapy, or psychological therapy, should be tested first if judged to improve the overall situation in a permanent manner. Patients with a complex situation can be subject to pain rehabilitation (interdisciplinary multimodal pain rehabilitation, IMMPR). IMMPR involves a coordinated effort of healthcare professionals with expertise in pain management aiming to reduce psychological distress, increase work ability and return to normal social activities and improve general health and life quality. Follow-up of patients undergoing IMMPR is routinely done by means of the Swedish Quality Registry for Pain Rehabilitation (SQRP), including rehabilitation in Primary Care and at specialized pain units.

Do quality of life, anxiety, depression and acceptance improve after interdisciplinary pain rehabilitation? A multicentre matched control study of acceptance and commitment therapy-based versus cognitive-behavioural therapy-based programmes.

OBJECTIVE: Interdisciplinary pain rehabilitation (IPR) usually employs a cognitive-behavioural therapeutic (CBT) approach. However, there is growing support for chronic pain treatments based on acceptance and commitment therapy (ACT). Most studies of ACT and CBT for chronic pain have evaluated their effects after psychological interventions, not after IPR. We compared the results of an ACT-based IPR programme with two CBT-based IPR programmes. METHODS: We used a retrospective multicentre pretest-posttest design with matched patient groups at three centres. Data were collected from the Swedish Quality Registry for Pain Rehabilitation before and after IPR participation. Participants completed the EQ-5D health-related quality of life questionnaire, the Chronic Pain Acceptance Questionnaire, (CPAQ) and the Hospital Anxiety and Depression Scale (HADS). Analyses were performed to compare the effects of the different interventions. RESULTS: Neither EQ-5D nor HADS depression scores were affected by the psychological approach used. The score changes on both CPAQ subscales (activity engagement and pain willingness) indicated significant improvements between admission and discharge at all centres. CONCLUSIONS: These findings indicate the effectiveness of using psychological approaches to manage chronic pain. Both CBT and ACT had a beneficial effect on most of the assessed health-related parameters.

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.

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.

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.

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.

Predictors and mediators of outcome in cognitive behavioral therapy for chronic pain: the contributions of psychological flexibility.

There is now a consensus in the literature that future improvements in outcomes obtained from cognitive behavioral therapy (CBT) for chronic pain will require research to identify patient and treatment variables that help explain outcomes. The first aim of this study was to assess whether pre-treatment scores on measures of psychological (in)flexibility, acceptance, committed action, cognitive (de)fusion, and values-based action predict outcomes in a multidisciplinary, multicomponent, group-based CBT program for adults with chronic pain. The second aim was to assess whether change scores on these same measures mediate outcomes in the treatment program. Participants were 232 people attending treatment for chronic pain. Of the psychological flexibility measures, only pre-treatment scores on the psychological inflexibility scale predicted outcomes; higher scores on this measure were associated with worse outcomes. However, change scores on each of the psychological flexibility measures separately mediated outcomes. The efficacy of CBT for chronic pain may be improved with a greater focus on methods that increase psychological flexibility.

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.

Maintenance of quality of life improvement for patients with chronic pain and obesity after interdisciplinary multimodal pain rehabilitation - A study using the Swedish Quality Registry for Pain Rehabilitation.

BACKGROUND: Throughout the world many people have both obesity and chronic pain, comorbidities that decrease Health-Related Quality of Life (HRQoL). It is uncertain whether patients with comorbid obesity can maintain improved HRQoL after Interdisciplinary Multimodal Pain Rehabilitation (IMMPR). METHODS: Data from 2016, 2017, and 2018 were obtained from a national pain database for Swedish specialized pain clinics and collected at three time points: Pre-IMMPR; Post- IMMPR; and 12-month follow-up (FU-IMMPR). Participants (N = 872) reported body weight, height, pain aspects, and HRQoL (RAND 36-Item Health Survey). Severe obesity (Body Mass Index, BMI ≥35 kg/m2 ) was defined according to WHO classifications. We used linear mixed regression models to examine BMI group differences in HRQoL over time. RESULTS: More than 25% of patients (224/872) were obese and nearly 30% (63/224) of these were severely obese. All BMI groups improved significantly in both physical and mental composites of HRQoL after IMMPR (Pre- vs. Post-IMMPR, p < .001). The improvements were maintained at a 12-month follow-up (Post- vs. FU-IMMPR, p > .05). The severe obesity group had the lowest physical health score and least improvement (pre- vs. FU-IMMPR, Cohen's d = o.422, small effect size). Severe obesity had negative impact on physical health (ß = -4.39, p < .05) after controlling for sociodemographic factors and pain aspects. CONCLUSION: Improvements in HRQoL after IMMPR were achieved and maintained across all weights, including patients with comorbid obesity. Only severe obesity was negatively associated with physical health aspects of HRQoL. SIGNIFICANCE: Patients with chronic pain and comorbid obesity achieve sustained Health-Related Quality of Life (HRQoL) improvements from Interdisciplinary Multimodal Pain Rehabilitation (IMMPR). This finding suggests that rehabilitation professionals should consider using IMMPR for patients with comorbid obesity even though their improvement may not reach the same level as for non-obese patients.

Return to work after interdisciplinary pain rehabilitation: One- and two-year follow-up based on the Swedish Quality Registry for Pain rehabilitation.

OBJECTIVES: To investigate: (i) changes in sick-leave benefits from 1 year prior to multimodal rehabilitation to 1 and 2 years after rehabilitation; (ii) sex differences in sick leave; and (iii) the impact of policy changes on sick leave. METHODS: All patients undergoing multimodal rehabilitation registered in a national pain database for 2007-11 (n = 7,297) were linked to the Swedish Social Insurance Agency database. Sick leave was analysed in 3-month periods: T0: 1 year before rehabilitation; T1: before start; T2: 1 year after; and T3: 2 years after rehabilitation. Four sick-leave benefit categories were constructed: no sick leave, part-time sick leave, full-time sick leave, and full-time permanent sick leave. The individual change in sick-leave category at each time-period was analysed. RESULTS: Sick-leave benefits increased from T0 to T1 (p < 0.001) and decreased from T1 to T3 (p < 0.001). Reductions were significant for both men and women from T1 to T3, but men had less sick-leave benefits at T2 and T3. Positive changes in sick-leave benefits at T2 and T3 were found both prior to and after policy changes, with less sick-leave benefits after policy changes at all time-points. CONCLUSION: Multimodal rehabilitation may positively influence sick-leave benefits for patients with chronic pain, regardless of their sick-leave situation, sex or policy changes.

The Relationship Between Posttraumatic Stress Disorder and Chronic Pain in People Seeking Treatment for Chronic Pain: The Mediating Role of Psychological Flexibility.

OBJECTIVES: The symptoms of posttraumatic stress disorder (PTSD) and chronic pain are thought to interact to increase the severity and impact of both conditions, but the mechanisms by which they interact remain unclear. This study examines the relationship between PTSD and chronic pain and whether indices of Psychological Flexibility mediate the relationship between these 2 conditions. MATERIALS AND METHODS: Standardized self-report measures of PTSD, pain severity, pain interference, depression, and psychological flexibility (pain-related acceptance, committed action, cognitive fusion, and values-based action) were obtained from 315 people seeking treatment for chronic pain who also reported at least 1 traumatic experience. RESULTS: People seeking treatment for chronic pain and reporting symptoms consistent with a current diagnosis of PTSD had significantly higher levels of pain severity, pain interference, depression, and cognitive fusion and lower levels of pain-related acceptance and committed action than those reporting symptoms below the diagnostic threshold for PTSD. Pain-related acceptance, committed action, cognitive fusion, and depression mediated the relationship between PTSD and pain severity/interference, with pain-related acceptance being the strongest mediator from the Psychological Flexibility model. DISCUSSION: Processes from the Psychological Flexibility model were identified as mediators of the relationship between PTSD and chronic pain in people seeking treatment for chronic pain. The Psychological Flexibility model may be useful as an overarching model to help understand the relationship between PTSD and chronic pain. It is possible that targeting pain-related acceptance, committed action, and cognitive fusion (among other processes) in the treatment of chronic pain may produce corresponding improvements in comorbid symptoms of PTSD when these are present and may reduce impacts of PTSD on outcomes of chronic pain. Conversely, targeting of these processes in the treatment of PTSD may produce similar improvements for symptoms of chronic pain. Further research to evaluate these possibilities is needed.