Prognostic factors for improved physical and emotional functioning one year after interdisciplinary rehabilitation in patients with chronic pain: Results from a national quality registry in Sweden

Clinical prediction model for interdisciplinary biopsychosocial rehabilitation in osteoarthritis patients

BACKGROUND

Osteoarthritis (OA) is a heterogenous condition, in which different subgroups are present. Individualized interdisciplinary multimodal pain treatments (IMPT) based on the biopsychosocial model have resulted in positive improvement of pain, health and disability in OA patients. Moreover, predictive factors for treatment success of IMPT in different musculoskeletal pain populations have been examined, but a clinical prediction model which informs whether an OA patient is expected to benefit or not from IMPT is currently lacking.

AIM

The aim was to develop and internally validate a clinical prediction model to inform patient-tailored care based on identified predictors for positive or negative outcomes of IMPT in patients with OA.

DESIGN

Longitudinal prospective cohort study.

SETTING

Center for Integral Rehabilitation at six locations in the Netherlands.

POPULATION

Chronic OA patients.

METHODS

Data in this study were collected during January 2019 until January 2022. Participants underwent a 10-week IMPT program based on the biopsychosocial model. Treatment success was defined by a minimal decrease from baseline of 9 points on the Pain Disability Index (PDI). Candidate predictors were selected by experts in IMPT and literature review. Backward logistic regression analysis was performed to develop the clinical predication model and bootstrap validation was performed for internal validation.

RESULTS

Overall, 599 OA patients were included, of which 324 experienced treatment success. Thirty-four variables were identified as possible predictors for good IMPT outcome. Age, gender, number of pain locations, PDI baseline score, maximal pain severity, use of pain medication and alcohol, work ability, brief illness perceptions questionnaire subscales timeline, consequences, identity and treatment control, pain catastrophizing scale and self-efficacy questionnaire score were found as predictors for treatment success. The internally validated model has an acceptable discriminative power of 0.71.

CONCLUSIONS

This study reports a specific clinical prediction model for good outcome of IMPT in patients with OA. The internally validated model has an acceptable discriminative power of 0.71.

CLINICAL REHABILITATION IMPACT

After external validation, this model could be used to develop a clinically useful decision tool.

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.

Do baseline patient reported outcome measures predict changes in self-reported function, following a chronic pain rehabilitation programme?

Background

Interdisciplinary pain management programmes, based on cognitive-behavioural principles, aim to improve physical and psychological functioning and enhance self-management in people living with chronic pain. Currently there is insufficient evidence about whether psychological, biological or social factors are predictive of positive outcomes following pain rehabilitation. This study aims to evaluate predictors of change in Brief Pain Inventory - pain interference score (BPI) in a clinical data set to determine whether age, sex and baseline outcome measures are predictive of improvement in pain interference following pain rehabilitation.

Methods

A retrospective, pragmatic observational analysis of routinely collected clinical data in two pain rehabilitation programmes, Balanced Life Programme (BLP) and Get Back Active (GBA) was conducted. Standard regression and hierarchical regression analyses were used to identify predictors of change to assess temporal changes in BPI. Responder analysis was also conducted.

Results

Standard regression analyses of 208 (BLP) and 310 (GBA) patients showed that higher baseline BPI and better physical performance measures predicted better improvement in BPI across both programmes. Hierarchical regression showed that age and sex accounted for 2.7% (BLP) and 0.002% (GBA) of the variance in change in BPI. After controlling for age and sex, the other measures explained an additional 23% (BLP) and 19% (GBA) of the variance, p = < .001 where BPI and physical performance measures were consistently statistically significant predictors, p < .05. Responder analysis also showed that pain interference and physical performance were significantly associated with improvement (p = < .0005).

Conclusions

The combination of high self-reported pain interference and better physical performance measures may be a useful indicator of who would benefit from interdisciplinary rehabilitation. Further validation of the results is required.

Psychometric Assessment of the Swedish version of the Work Ability Index in Patients with Chronic Pain in Specialized Care

OBJECTIVE

To evaluate the construct validity and internal consistency of the Work Ability Index (WAI) in patients with chronic pain in secondary and tertiary care.

METHODS

Cross-sectional study based on 200 patients with chronic pain (> 3 months), with a final sample of 118 participants, 18-64-years-old. Construct validity was assessed by exploratory factor analysis for the structural validity of the WAI, and by correlating the WAI with EuroQol EQ-5D, Brief Pain Inventory pain severity and interference, Patient Health Questionnaire and Generalized Anxiety Disorder scales. The study also assessed the discriminant validity of the WAI for occupational status, and the validity of the single-item work ability score. Reliability was assessed by internal consistency.

RESULTS

A single-factor model of WAI was supported. Internal consistency was good. Moderate correlations were found, except for Brief Pain Inventory pain severity, where the correlation was weak; hence, both convergent and divergent validity of the WAI were supported. The work ability score correlated strongly with the total WAI, and the discriminant validity for both was good.

CONCLUSION

In patients with chronic pain in specialized care, the WAI and the work ability score displayed acceptable construct validity and internal consistency, supporting their use in a clinical context and research.

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.

[Results of a pilot study on the role of therapy expectation in interdisciplinary multimodal pain therapy for chronic back pain]

Hintergrund

Chronische Rückenschmerzen sind eine schwerwiegende und global sehr häufig auftretende Erkrankung mit enormen persönlichen sowie sozioökonomischen Auswirkungen. Die interdisziplinäre multimodale Schmerztherapie (IMST) ist eines der wenigen evidenzbasierten Behandlungsverfahren für chronische Schmerzen. Obwohl bekannt ist, dass Schmerzen sowie deren Chronifizierung und Behandlung von den persönlichen Erwartungen der Patienten beeinflusst werden, gibt es wenige etablierte Interventionen oder Richtlinien für eine aktive Modulation dieses Effekts.

Ziel der Arbeit

Wir möchten mit dieser Arbeit die Rolle der Erwartung als Prädiktor für Schmerzen sowie schmerzbezogene Beeinträchtigung in der klinischen Praxis verdeutlichen und präsentieren hierzu beispielhaft explorative Pilotdaten einer Beobachtungskohorte unserer Klinik.

Material und Methoden

Die Untersuchung zeigt erste Daten einer prospektiven longitudinalen Beobachtungsstudie bestehend aus bis zu 41 Patienten mit chronischen Rückenschmerzen, die im Setting einer IMST am Essener Rückenschmerz-Zentrum behandelt wurden. Es wurden Daten zum Zeitpunkt der Aufnahme (T0) und der Entlassung (T1) sowie drei Monate nach Therapieende (T2) erhoben. Primäre Endpunkte waren die Schmerzintensität und die Schmerzbeeinträchtigung. Zusätzlich erfassten wir die Therapieerwartung zum Zeitpunkt der Aufnahme als möglichen Prädiktor. Die Bedeutung der vor der Therapie erhobenen Therapieerwartung wurde mittels linearer Regression erfasst.

Ergebnisse

Die IMST führte zu einer signifikanten Besserung in Bezug auf die Schmerzintensität und -beeinträchtigung. Der Effekt auf die Schmerzintensität war über den Zeitraum von drei Monaten nach Therapieende anhaltend und die Beeinträchtigung sank in diesem Zeitraum weiter signifikant.

Diskussion

Erwartung war ein signifikanter Prädiktor für die Abnahme der Schmerzintensität und erklärte ca. 15 % der Varianz. In der klinischen Praxis sollten daher valide Methoden etabliert werden, negative Erwartungen zu reduzieren und positive Erwartungen zu fördern.

The Mediating Role of Pain Catastrophizing on the Association Between Depression and Pain Severity and Interference Among Elderly Asian Immigrants with Chronic Pain

Purpose

The association between depression and chronic pain is well established. However, few studies have examined the pathways from depression to chronic pain. The present cross-cultural study aimed to test the mediating effects of pain catastrophizing on associations between depression and chronic pain (eg, pain severity, pain intensity) among Korean American elderly.

Patients and Methods

A total of 132 elderly Korean Americans with chronic pain were recruited from elderly daycare centers and Korean ethnic churches in the community. For mediation analyses, structural equation modeling with full information maximum likelihood estimation method was used. The bias-corrected bootstrap confidence interval (CI) method for inferential tests of the indirect effects was also conducted in mediation analysis.

Results

The results indicated that the proportion of comorbid depression and chronic pain was 45.7%. Elderly Korean Americans with depression scored higher in pain severity, pain interference, and pain catastrophizing than those without depression. Pain catastrophizing was found to have a significant mediating effect on the relationship between depression and pain severity (indirect effect = 0.147, Bootstrap 95% CI = [0.079, 0.226]), controlling for demographic covariates, comorbidities and pain area. Pain catastrophizing also mediated the relationship between depression and pain interference (indirect effect =0.164, Bootstrap 95% CI = [0.097, 0.244]), controlling for the covariates.

Conclusion

These findings add to the literature by providing evidence that pain catastrophizing plays a role in high levels of pain severity and pain interference comorbid chronic pain and depression in Asian elderly immigrants. Appropriate culturally tailored programs to redirect pain catastrophizing cognitive process should be developed and provided for elderly Asian Americans to reduce chronic pain disparity.

Wrist-Worn Activity Trackers in Laboratory and Free-Living Settings for Patients With Chronic Pain: Criterion Validity Study

BACKGROUND

Physical activity is evidently a crucial part of the rehabilitation process for patients with chronic pain. Modern wrist-worn activity tracking devices seemingly have a great potential to provide objective feedback and assist in the adoption of healthy physical activity behavior by supplying data of energy expenditure expressed as metabolic equivalent of task units (MET). However, no studies of any wrist-worn activity tracking devices' have examined criterion validity in estimating energy expenditure, heart rate, or step count in patients with chronic pain.

OBJECTIVE

The aim was to determine the criterion validity of wrist-worn activity tracking devices for estimations of energy expenditure, heart rate, and step count in a controlled laboratory setting and free-living settings for patients with chronic pain.

METHODS

In this combined laboratory and field validation study, energy expenditure, heart rate, and step count were simultaneously estimated by a wrist-worn activity tracker (Fitbit Versa), indirect calorimetry (Jaeger Oxycon Pro), and a research-grade hip-worn accelerometer (ActiGraph GT3X) during treadmill walking at 3 speeds (3.0 km/h, 4.5 km/h, and 6.0 km/h) in the laboratory setting. Energy expenditure and step count were also estimated by the wrist-worn activity tracker in free-living settings for 72 hours. The criterion validity of each measure was determined using intraclass and Spearman correlation, Bland-Altman plots, and mean absolute percentage error. An analysis of variance was used to determine whether there were any significant systematic differences between estimations.

RESULTS

A total of 42 patients (age: 25-66 years; male: 10/42, 24%; female: 32/42, 76%), living with chronic pain (duration, in years: mean 9, SD 6.72) were included. At baseline, their mean pain intensity was 3.5 (SD 1.1) out of 6 (Multidimensional Pain Inventory, Swedish version). Results showed that the wrist-worn activity tracking device (Fitbit Versa) systematically overestimated energy expenditure when compared to the criterion standard (Jaeger Oxycon Pro) and the relative criterion standard (ActiGraph GT3X). Poor agreement and poor correlation were shown between Fitbit Versa and both Jaeger Oxycon Pro and ActiGraph GT3X for estimated energy expenditure at all treadmill speeds. Estimations of heart rate demonstrated poor to fair agreement during laboratory-based treadmill walks. For step count, the wrist-worn devices showed fair agreement and fair correlation at most treadmill speeds. In free-living settings; however, the agreement for step count between the wrist-worn device and waist-worn accelerometer was good, and the correlation was excellent.

CONCLUSIONS

The wrist-worn device systematically overestimated energy expenditure and showed poor agreement and correlation compared to the criterion standard (Jaeger Oxycon Pro) and the relative criterion standard (ActiGraph GT3X), which needs to be considered when used clinically. Step count measured with a wrist-worn device, however, seemed to be a valid estimation, suggesting that future guidelines could include such variables in this group with chronic pain.

The Context Matters: A Retrospective Analysis of Life Stage at Chronic Pain Onset in Relation to Pain Characteristics and Psychosocial Outcomes

BACKGROUND

Developmental life stage at chronic pain onset differs among chronic pain patients. Although pain affects multiple life domains, it is unknown whether the timing of chronic pain onset relates to pain characteristics and psychosocial outcomes. The purpose of this retrospective study was to investigate differences in pain characteristics and psychosocial outcomes in patients at different developmental life stages at chronic pain onset.

METHODS

Cross-sectional baseline data from the Swedish Quality Registry for Pain Rehabilitation (2009 to 2016) were used, selecting the middle-aged patients (45-65 years, n=6225) reporting chronic nonmalignant pain. Patients were categorized into three groups, depending on their developmental life stage at chronic pain onset: early onset (age ≤30 years), intermediate onset (age 31-45 years), and late onset (age ≥46 years). Pain characteristics and psychosocial outcomes were assessed with validated self-reported measures.

RESULTS

One-way MANCOVA indicated differences in number of pain locations and psychosocial outcomes among the groups. Post hoc analysis showed differences in the trends for how groups differed on outcome domains. Overall, patients with earlier chronic pain onset showed significantly poorer psychosocial outcomes and more spreading of pain.

CONCLUSION

Developmental life stage at chronic pain onset is associated with different pain outcomes. Pain onset early in life is linked to worse outcomes in multiple domains, pointing to a need for identifying these patients early.

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.