Logo: to the web site of Uppsala University

Chronic pain (> 3 months) is associated with balance impairments and risk of falls. This thesis explored how well the Mini-BESTest captures dynamic balance in patients with chronic pain referred to specialized pain care, focusing on ecological validity and patient perspectives informed by behavioral medicine. It also examined how physical, psychosocial, pharmacological, and behavioral factors relate to dynamic balance and perceived challenges in everyday life.

Specific aims: Studies I–II evaluated the Mini-BESTest’s validity, reliability, and patients’ perspectives on balance. Study III examined patient characteristics and opioid-related factors associated with balance, and Study IV explored characteristics linked to long-term and prescription opioid use disorder (P-OUD).

Methods: All studies included patients with chronic pain referred to specialized pain care. Study I (n = 180) assessed construct validity, and Study II (n = 53 + 15) assessed test-retest reliability and explored perceptions of balance through qualitative interviews. Studies III (n = 179) and IV (n = 339) analyzed dynamic balance and opioid use in relation to biopsychosocial characteristics using regression models.

Results: Studies I and II supported the Mini-BESTest’s construct validity, internal consistency, and test-retest reliability, but did not fully reflect patients’ perceptions of balance in everyday life. In Study III, poorer dynamic balance was associated with oxycodone use, older age, lower education, low pain self-efficacy, and low physical activity. In Study IV, long-term opioid use was linked to longer pain duration, unemployment, more catastrophizing, lower quality of life, and worse dynamic balance. P-OUD was associated with younger age, trauma exposure, catastrophizing, and fear of movement, but not with balance.

Conclusion: The Mini-BESTest is clinically relevant in specialized pain care, given its measurement properties and associations with opioid use and biopsychosocial factors influencing treatment outcomes. However, it does not fully capture balance as experienced in everyday life, leaving unmet needs in assessment and treatment. Based on findings from this thesis, a conceptual model grounded in behavioral medicine is introduced, emphasizing the need for multidimensional approaches reflecting patients’ everyday challenges and abilities to participate in meaningful activities. These findings underscore importance of integrating patient-reported experiences and contextual factors into balance assessment and treatment.

Background

This study aimed to examine: (a) characteristics associated with long-term opioid use and (b) characteristics associated with problematic opioid use, here defined as prescription opioid use disorder (P-OUD), in patients referred to specialised pain care.

Methods

This cross-sectional study utilised baseline data from a clinical chronic pain cohort. Eligible participants included adults > 18 years old, not undergoing cancer treatment, had pain > 3 months, and had been referred to a specialised pain care centre in Sweden. Bivariate logistic regression and multivariable logistic regression with forward selection were used to examine the associations between biopsychosocial variables and either long-term opioid use or P-OUD.

Results

Of the 339 patients included, 194 (57%) were using opioids, 159 (47%) had long-term opioid use (> 90 days), and 34 (21% of those with long-term opioid use) had P-OUD. Longer pain duration, unemployment, more pain catastrophising, lower health-related quality of life, and worse balance increased the likelihood of long-term opioid use. Long-term use of high doses was associated with a greater prevalence of psychiatric and cognitive-behavioural problems compared to long-term use at low to moderate doses. Long-term opioid use, younger age, trauma exposure, more pain catastrophising, and fear of movement increased the likelihood of P-OUD.

Conclusions

Our results demonstrate the importance of identifying and treating salient factors that may sustain both the pain condition and long-term opioid use. Many of the biopsychosocial variables associated with long-term opioid use and P-OUD can be addressed within interdisciplinary pain management and rehabilitation programmes.

Significance

This study is part of the U-PAIN cohort study on a clinical sample from a highly specialised pain centre in Sweden. It is based on a deep and thorough characterisation of patients referred to the clinic to evaluate risks and benefits of opioid therapy in chronic pain. It adds valuable information on the complexity of opioid therapy in chronic pain; the results highlight the need for interdisciplinary multimodal evaluation and treatment.

Background: This study aimed to examine: (a) characteristics associated with long-term opioid use and (b) characteristics associated with problematic opioid use, here defined as prescription opioid use disorder (P-OUD), in patients referred to specialised pain care.

Methods: This cross-sectional study utilised baseline data from a clinical chronic pain cohort. Eligible participants included adults > 18 years old, not undergoing cancer treatment, had pain > 3 months, and had been referred to a specialised pain care centre in Sweden. Bivariate logistic regression and multivariable logistic regression with forward selection were used to examine the associations between biopsychosocial variables and either long-term opioid use or P-OUD.

Results: Of the 339 patients included, 194 (57%) were using opioids, 159 (47%) had long-term opioid use (> 90 days), and 34 (21% of those with long-term opioid use) had P-OUD. Longer pain duration, unemployment, more pain catastrophising, lower health-related quality of life, and worse balance increased the likelihood of long-term opioid use. Long-term use of high doses was associated with a greater prevalence of psychiatric and cognitive-behavioural problems compared to long-term use at low to moderate doses. Long-term opioid use, younger age, trauma exposure, more pain catastrophising, and fear of movement increased the likelihood of P-OUD.

Conclusions: Our results demonstrate the importance of identifying and treating salient factors that may sustain both the pain condition and long-term opioid use. Many of the biopsychosocial variables associated with long-term opioid use and P-OUD can be addressed within interdisciplinary pain management and rehabilitation programmes.

Background

Balance assessment scales are important clinical tests to identify balance impairments. Chronic pain (> 3 months) is associated with impaired dynamic balance; however, very few balance assessment scales are psychometrically evaluated for the population. The purpose of this study was to evaluate the construct validity and internal consistency of the Mini-BESTest for individuals with chronic pain in specialized pain care.

Methods

In this cross-sectional study, 180 individuals with chronic pain (> 3 months) were assessed with the Mini-BESTest and included in the analyses. For construct validity, five alternative factor structures were evaluated using a confirmatory factor analysis. In addition, we tested the a priori hypotheses about convergent validity with the 10-meter walk test, and divergent validity with the Brief Pain Inventory (BPI): pain intensity, the Tampa Scale of Kinesiophobia-11 (TSK-11), and the Pain Catastrophizing Scale (PCS-SW). Internal consistency was evaluated for the model with the best fit.

Results

A one-factor model with added covariance via the modification indices showed adequate fit indices. In line with our hypotheses, Mini-BESTest showed convergent validity (r_s = > 0.70) with the 10-meter walk test, and divergent validity (r_s = < 0.50) with BPI pain intensity, TSK-11, and PCS-SW. Internal consistency for the one-factor model was good (α = 0.92).

Conclusions

Our study supported the construct validity and internal consistency of the Mini-BESTest for measuring balance in individuals with chronic pain, who were referred to specialized pain care. The one-factor model showed an adequate fit. In comparison, models with subscales did not reach convergence, or showed high correlations between subscales, implying that Mini-BESTest is measuring one construct in this sample. We, therefore, propose using the total score, instead of subscale scores, for individuals with chronic pain. However, further studies are necessary to establish the reliability of the Mini-BESTest in the population.

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.

Effective interventions are needed for return-to-work (RTW) for individuals with chronic pain on long-term sick leave. In this study, a behavioral medicine physiotherapy protocol was systematically replicated and added to workplace components. The intervention was evaluated for fidelity and effects on target activities and work ability. A single-case experimental design was used with five participants. Daily and weekly ratings of personalized target activities at work as well as work ability were carried out throughout the study period of 26-28 weeks. Effects of the behavioral medicine physiotherapy intervention were evaluated for each individual using visual analysis of displayed graphs and quantitative non-overlap methods. Goal achievement for target activities was reviewed. Three participants completed the intervention. The results indicated an effect from the behavioral medicine physiotherapy intervention on task-specific self-efficacy for target activities, but no consistent effect on experience of target activities or work ability. All three participants had increased function in target activities in line with pre-defined goals. Fidelity to the intervention manual was good. Behavioral medicine physiotherapy can be successfully adapted to work disability and was here replicated in an RTW context for individuals with chronic pain. The intervention protocol should be further evaluated in large-scale studies.

Objectives: To examine acceptability of study participation and feasibility of (1) recruitment, (2) data collection and (3) outcome measures for the prospective U-PAIN cohort.

Design: Internal feasibility study of a prospective cohort.

Participants and setting: 64 patients, >18 years, with chronic pain at a multidisciplinary pain centre at a university hospital in Sweden.

Outcome measures: Acceptability of study participation was measured with a study-specific 10-item Likert scale. A score <3 was considered feasible, for the two items that assessed respondent burden a higher score indicated lesser participant burden and a score >3 was feasible. Recruitment was assessed by participation rates at baseline and retention at the 1-year follow-up, with threshold values for feasibility at 75% and 80%, respectively. Data collection and outcome measures were examined by completions rates of study procedures (90% was considered feasible), sample scores, internal consistency (alpha>0.70 was considered feasible), and agreement between self-reported data and data retrieved from medical records on opioid use (ICC or kappa>0.60 was considered feasible).

Results: Acceptability for study procedures was feasible, but participation rates were low: 25%. The retention rate at 1-year follow-up was 81% for those included in the feasibility study, that is, filling out computerised patient-reported outcome measures, and 65% for those using paper and pencil format. The completion rates for the different data collection methods ranged from 83% to 95%. Agreement between self-reported opioid use and prescribed dose and between opioid use disorder according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), and clinical International Classification of Diseases-10 (ICD-10) diagnoses for opioid dependence were almost perfect (kappa=0.91and kappa=0.90, respectively).

Conclusions: This feasibility study has helped to explore and improve methods for recruitment, data collection and use of outcome measures for the U-PAIN cohort. Low participation rate and high refusal rate at baseline is a challenge that needs to be further addressed.

Background: The use of opioids to relieve chronic pain has increased during the last decades, but experiences of chronic opioid therapy (COT) (> 90 days) point at risks and loss of beneficial effects. Still, some patients report benefits from opioid medication, such as being able to stay at work. Guidelines for opioid use in chronic pain do not consider the individual experience of COT, including benefits and risks, making the first person perspective an important scientific component to explore. The aim of this study was to investigate the lived experience of managing chronic pain with opioids in a sample who have severe chronic pain but are able to manage their pain sufficiently to remain at work.

Methods: We used a qualitative research design: interpretative phenomenological analysis. Ten individuals with chronic pain and opioid therapy were purposively sampled in Swedish tertiary care.

Results: Three super-ordinate themes emerged from the analyses: Without opioids, the pain becomes the boss; Opioids as a salvation and a curse, and Acknowledgement of the pain and acceptance of opioid therapy enables transition to a novel self. The participants used opioids to regain control over their pain, thus reclaiming their wanted life and self, and sense of control over one's life-world. Using opioids to manage pain was not unproblematic and some of the participants had experienced a downward spiral of escalating pain and uncontrollable opioid use, and stigmatisation.

Conclusions: All participants emphasised the importance of control, regarding both pain and opioid use. To accomplish this, trust between participants and health care providers was essential for satisfactory treatment. Regardless of the potential sociocultural benefits of staying at work, participants had experiences of balancing positive and negative effects of opioid therapy, similar to what previous qualitative research has found. Measurable improvement of function and quality of life, may justify the long-term use of opioids in some cases. However, monitoring of adverse events should be mandatory. This requires close cooperation and a trusting relationship between the patients and their health care provider.