Subgrouping of Low Back Pain Patients for Targeting Treatments: Evidence from Genetic, Psychological, and Activity-related Behavioral Approaches

The Effect of Everyday-Life Social Contact on Pain

Pain is a biopsychosocial phenomenon, resulting from the interplay between physiological and psychological processes and social factors. Given that humans constantly interact with others, the effect of social factors is particularly relevant. Documenting the significance of the social modulation of pain, an increasing number of studies have investigated the effect of social contact on subjective pain intensity and pain-related physiological changes. While evidence suggests that social contact can alleviate pain, contradictory findings indicate an increase in pain intensity and a deterioration of pain coping strategies. This evidence primarily stems from studies examining the effect of social contact on pain within highly controlled laboratory conditions. Moreover, pain assessments often rely on one-time subjective reports of average pain intensity across a predefined period. Ecological momentary assessments (EMAs) can circumvent these problems, as they can capture diverse aspects of behavior and experiences multiple times a day, in real time, with high resolution, and within naturalistic and ecologically valid settings. These multiple measures allow for the examination of fluctuations of pain symptoms throughout the day in relation to affective, cognitive, behavioral, and social factors. In this opinion paper, we review the current state and future relevance of EMA-based social pain research in daily life. Specifically, we examine whether everyday-life social support reduces or enhances pain. The first part of the paper provides a comprehensive overview of the use of EMA in pain research and summarizes the main findings. The review of the relatively limited number of existing EMA studies shows that the association between pain and social contact in everyday life depends on numerous factors, including pain syndromes, temporal dynamics, the nature of social interactions, and characteristics of the interaction partners. In line with laboratory research, there is evidence that everyday-life social contact can alleviate, but also intensify pain, depending on the type of social support. Everyday-life emotional support seems to reduce pain, while extensive solicitous support was found to have opposite effects. Moreover, positive short-term effects of social support can be overshadowed by other symptoms such as fatigue. Overall, gathering and integrating experiences from a patient's social environment can offer valuable insights. These insights can help interpret dynamics in pain intensity and accompanying symptoms such as depression or fatigue. We conclude that factors determining the reducing versus enhancing effects of social contact on pain need to be investigated more thoroughly. We advocate EMA as the assessment method of the future and highlight open questions that should be addressed in future EMA studies on pain and the potential of ecological momentary interventions for pain treatment.

Determinants of outcomes for patients with chronic low back pain and fear-avoidance beliefs following treatment with specific stabilisation exercises

BACKGROUND

Specific stabilisation exercises (SSE) can combat the debilitating effects of chronic non-specific low back pain (CLBP), improve disability, pain and fear-avoidance beliefs (FAB).

OBJECTIVE

To elicit the determinants of outcome in patients with CLBP with associated FABs after treatment with SSE.

METHOD

Twenty-nine patients (20 females) with CLBP were classified using FAB questionnaire into high or low Work and Physical Activity (PA) subscales. After 4-week treatment, evaluations were done for pain, disability and lumbar spine active range of motion (AROM). Data was analysed exploratory-descriptively with a significance level set at p< 0.05.

RESULTS

Participants were aged 55.24 ± 11.91 years. They scored 19 (65.5%) and 5 (17.2%) respectively on Work and PA subscales. The post-intervention evaluation showed significant differences in all outcomes, but no significant difference between patients with high or low FAB scores for both subscales. PA scores correlated significantly with pain while work scores correlated significantly with disability. Participants' gender predicted disability, pain and AROM with moderate to large effect sizes.

CONCLUSION

SSE can potentially improve disability, pain and range of motion for patients with chronic low back pain regardless of FABQ status. Gender and baseline patient status are potential determinants of outcome of treatment using SSE.

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.

Development, evaluation and implementation of a digital behavioural health treatment for chronic pain: study protocol of the multiphase DAHLIA project

INTRODUCTION

Chronic pain affects about 20%-40% of the population and is linked to mental health outcomes and impaired daily functioning. Pharmacological interventions are commonly insufficient for producing relief and recovery of functioning. Behavioural health treatment is key to generate lasting benefits across outcome domains. However, most people with chronic pain cannot easily access evidence-based behavioural interventions. The overall aim of the DAHLIA project is to develop, evaluate and implement a widely accessible digital behavioural health treatment to improve well-being in individuals with chronic pain.

METHODS AND ANALYSIS

The project follows the four phases of the mHealth Agile Development and Evaluation Lifecycle: (1) development and pre-implementation surveillance using focus groups, stakeholder interviews and a business model; (2) iterative optimisation studies applying single case experimental design (SCED) method in 4-6 iterations with n=10 patients and their healthcare professionals per iteration; (3) a two-armed clinical randomised controlled trial enhanced with SCED (n=180 patients per arm) and (4) interview-based post-market surveillance. Data analyses include multilevel modelling, cost-utility and indicative analyses.In October 2021, inter-sectorial partners are engaged and funding is secured for four years. The treatment content is compiled and the first treatment prototype is in preparation. Clinical sites in three Swedish regions are informed and recruitment for phase 1 will start in autumn 2021. To facilitate long-term impact and accessibility, the treatment will be integrated into a Swedish health platform (www.1177.se), which is used on a national level as a hub for advice, information, guidance and e-services for health and healthcare.

ETHICS AND DISSEMINATION

The study plan has been reviewed and approved by Swedish ethical review authorities. Findings will be actively disseminated through peer-reviewed journals, conference presentations, social media and outreach activities for the wider public.

TRIAL REGISTRATION NUMBER

NCT05066087.

Feasibility of concussion rehabilitation approaches tailored to psychological coping styles: A randomized controlled trial

OBJECTIVE

To evaluate the feasibility of a clinical trial involving participants with concussion randomized to treatments designed to address fear avoidance or endurance coping, which are risk factors for disability. A secondary objective was to evaluate whether each treatment could effect selective change on targeted coping outcomes.

DESIGN

Randomized controlled trial.

SETTING

Outpatient concussion clinics.

PARTICIPANTS

73 adults (M=42.5 years old) who had persistent post-concussion symptoms and high avoidance or endurance behavior were enrolled at M=12.9 weeks post injury. 10 participants did not complete treatment.

INTERVENTIONS

Participants were randomized to an interdisciplinary rehabilitation program delivered via videoconferencing and tailored to avoidance coping (graded exposure therapy; GET) or endurance coping (operant condition-based pacing strategies plus mindfulness training; Pacing+).

MAIN OUTCOME MEASURES

Feasibility outcomes included screening efficiency, accrual, credibility, treatment fidelity, adherence, and retention. Avoidance was measured with the Fear Avoidance Behavior after Traumatic Brain Injury questionnaire and endurance behavior with the Behavioral Response to Illness Questionnaire.

RESULTS

Screening efficiency, or the proportion of clinic patients who were assessed for eligibility, was 44.5% (275/618). 65.8% (73/111) of eligible patients were randomized (n=37 to GET and n=36 to Pacing+), meeting accrual targets. 91.7% (55/60) of participants perceived treatment as credible. Therapists covered M=96.8% of essential prescribed elements, indicating excellent fidelity. The majority (71.2%; 47/66) of participants consistently attended treatment sessions and completed between-session homework. Retention was strong, with 65 of 73 (89%) randomized participants completing the outcome assessment. GET was associated with greater post-treatment reductions in avoidance behavior compared to Pacing+ (Cohen's d_{repeated measures} = 0.81), whereas the treatment approach-specific effect of Pacing+ on endurance behavior was less pronounced (Cohen's d_{repeated measures} = 0.39).

CONCLUSIONS

Findings support a future efficacy-focused clinical trial. GET has the potential to selectively reduce fear avoidance behavior after concussion, and, via this mechanism, to prevent or reduce disability.

How does individualised physiotherapy work for people with low back pain? A Bayesian Network analysis using randomised controlled trial data

PURPOSE

Individualised physiotherapy is an effective treatment for low back pain. We sought to determine how this treatment works by using randomised controlled trial data to develop a Bayesian Network model.

METHODS

300 randomised controlled trial participants (153 male, 147 female, mean age 44.1) with low back pain (of duration 6-26 weeks) received either individualised physiotherapy or advice. Variables with potential to explain how individualised physiotherapy works were included in a multivariate Bayesian Network model. Modelling incorporated the intervention period (0-10 weeks after study commencement-"early" changes) and the follow-up period (10-52 weeks after study commencement-"late" changes). Sequences of variables in the Bayesian Network showed the most common direct and indirect recovery pathways followed by participants with low back pain receiving individualised physiotherapy versus advice.

RESULTS

Individualised physiotherapy directly reduced early disability in people with low back pain. Individualised physiotherapy exerted indirect effects on pain intensity, recovery expectations, sleep, fear, anxiety, and depression via its ability to facilitate early improvement in disability. Early improvement in disability, led to an early reduction in depression both directly and via more complex pathways involving fear, recovery expectations, anxiety, and pain intensity. Individualised physiotherapy had its greatest influence on early change variables (during the intervention period).

CONCLUSION

Individualised physiotherapy for low back pain appears to work predominately by facilitating an early reduction in disability, which in turn leads to improvements in other biopsychosocial outcomes. The current study cannot rule out that unmeasured mechanisms (such as tissue healing or reduced inflammation) may mediate the relationship between individualised physiotherapy treatment and improvement in disability. Further data-driven analyses involving a broad range of plausible biopsychosocial variables are recommended to fully understand how treatments work for people with low back pain.

TRIALS REGISTRATION

ACTRN12609000834257.

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.

Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for “precision medicine” or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

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.

The OPTIMIZE study: protocol of a pragmatic sequential multiple assessment randomized trial of nonpharmacologic treatment for chronic, nonspecific low back pain

BACKGROUND

Low back pain is a prevalent condition that causes a substantial health burden. Despite intensive and expensive clinical efforts, its prevalence is growing. Nonpharmacologic treatments are effective at improving pain-related outcomes; however, treatment effect sizes are often modest. Physical therapy (PT) and cognitive behavioral therapy (CBT) have the most consistent evidence of effectiveness. Growing evidence also supports mindfulness-based approaches. Discussions with providers and patients highlight the importance of discussing and trying options to find the treatment that works for them and determining what to do when initial treatment is not successful. Herein, we present the protocol for a study that will evaluate evidence-based, protocol-driven treatments using PT, CBT, or mindfulness to examine comparative effectiveness and optimal sequencing for patients with chronic low back pain.

METHODS

The Optimized Multidisciplinary Treatment Programs for Nonspecific Chronic Low Back Pain (OPTIMIZE) Study will be a multisite, comparative effectiveness trial using a sequential multiple assessment randomized trial design enrolling 945 individuals with chronic low back pain. The co-primary outcomes will be disability (measured using the Oswestry Disability Index) and pain intensity (measured using the Numerical Pain Rating Scale). After baseline assessment, participants will be randomly assigned to PT or CBT. At week 10, participants who have not experienced at least 50% improvement in disability will be randomized to cross-over phase-1 treatments (e.g., PT to CBT) or to Mindfulness-Oriented Recovery Enhancement (MORE). Treatment will consist of 8 weekly sessions. Long-term outcome assessments will be performed at weeks 26 and 52.

DISCUSSION

Results of this study may inform referring providers and patients about the most effective nonoperative treatment and/or sequence of nonoperative treatments to treat chronic low back pain.

TRIAL REGISTRATION

This study was prospectively registered on March 1, 2019, with Clinicaltrials.gov under the registration number NCT03859713 (https://clinicaltrials.gov/ct2/show/NCT03859713).

Does Electroacupuncture Have Different Effects on Peripheral and Central Sensitization in Humans: A Randomized Controlled Study

Background

Acupuncture is used to reduce chronic musculoskeletal pain. The common mechanism underlying these types of pain are peripheral and/or central sensitization. In the clinical setting, it is difficult to separate the peripheral from the central component of pain. Heat/capsaicin 45°C/0.075%-induced hyperalgesia provides a stable, human central sensitization model in which the peripheral component is also assessed.

Aim

This randomized, sham-controlled study aimed to investigate the effect of electroacupuncture (EA) on the severity of heat (peripheral sensitization) and mechanical hyperalgesia (central sensitization) in a heat/capsaicin pain model in humans.

Methods

Twenty-six healthy young participants (24 ± 3.9 years) were recruited. After baseline assessment, heat/capsaicin 45°C/0.075% was applied to the non-dominant forearm to induce hyperalgesia. The primary outcome measures were the size of the area of mechanical hyperalgesia, intensity of pain to heat stimulation and heat pain thresholds. The intensity of pain was recorded using modified 10-cm visual analogues scales (VAS). Participants were assessed at 70 min after the initial application of capsaicin then randomly allocated to receive either real electroacupuncture (REA, n = 14) or sham non-invasive EA (SEA, n = 12) for 30 min. The main outcome measures were assessed again immediately and then 90 min following EA. Credibility of blinding was assessed. Data were analyzed with t-tests or analysis of variance (ANOVA) where appropriate.

Results

After the model was established, the area of mechanical hyperalgesia was formed (55.64 cm²), as was heat hyperalgesia, as the rating to heat stimulation, increased from 2/10 to 6/10. The REA and SEA groups were comparable. Immediately after the allocated acupuncture treatment, the rating to heat stimulation was statistically significantly lower in the REA group (2.94 ± 1.64) than in the SEA group (4.62 ± 2.26) (p < 0.05). The area of mechanical hyperalgesia reduced significantly without any group difference. No group difference was detected in heat pain threshold. Blinding of the participants was successful.

Conclusion

Peripheral and central sensitization in the heat/capsaicin 45°C/0.075% model responded to EA differently, suggesting that acupuncture analgesia could vary, depending on the types of pain. This observation may explain some inconsistent findings from clinical trials of acupuncture.

The importance of emotional distress, cognitive behavioural factors and pain for life impact at baseline and for outcomes after rehabilitation – a SQRP study of more than 20,000 chronic pain patients

Background and aims

Although literature concerning chronic pain patients indicates that cognitive behavioural variables, specifically acceptance and fear of movement/(re)injury, are related to life impact, the relative roles of these factors in relation to pain characteristics (e.g. intensity and spreading) and emotional distress are unclear. Moreover, how these variables affect rehabilitation outcomes in different subgroups is insufficiently understood. This study has two aims: (1) to investigate how pain, cognitive behavioural, and emotional distress variables intercorrelate and whether these variables can regress aspects of life impact and (2) to analyse whether these variables can be used to identify clinically meaningful subgroups at baseline and which subgroups benefit most from multimodal rehabilitation programs (MMRP) immediately after and at 12-month follow-up.

Methods

Pain aspects, background variables, psychological distress, cognitive behavioural variables, and two life impact variables were obtained from the Swedish Quality Registry for Pain Rehabilitation (SQRP) for chronic pain patients. These data were analysed mainly using advanced multivariate methods.

Results

The study includes 22,406 chronic pain patients. Many variables, including acceptance variables, showed important contributions to the variation in clinical presentations and in life impacts. Based on the statistically important variables considering the clinical presentation, three clusters/subgroups of patients were identified at baseline; from the worst clinical situation to the relatively good situation. These clusters showed significant differences in outcomes after participating in MMRP; the subgroup with the worst situation at baseline showed the most significant improvements.

Conclusions

Pain intensity/severity, emotional distress, acceptance, and life impacts were important for the clinical presentation and were used to identify three clusters with marked differences at baseline (i.e. before MMRP). Life impacts showed complex relationships with acceptance, pain intensity/severity, and emotional distress. The most significant improvements after MMRP were seen in the subgroup with the lowest level of functioning before treatment, indicating that patients with complex problems should be offered MMRP.

Implications

This study emphasizes the need to adopt a biopsychosocial perspective when assessing patients with chronic pain. Patients with chronic pain referred to specialist clinics are not homogenous in their clinical presentation. Instead we identified three distinct subgroups of patients. The outcomes of MMRP appears to be related to the clinical presentation. Thus, patients with the most severe clinical presentation show the most prominent improvements. However, even though this group of patients improve they still after MMRP show a complex situation and there is thus a need for optimizing the content of MMRP for these patients. The subgroup of patients with a relatively good situation with respect to pain, psychological distress, coping and life impact only showed minor improvements after MMRP. Hence, there is a need to develop other complex interventions for them.

Who benefits from multimodal rehabilitation - an exploration of pain, psychological distress, and life impacts in over 35,000 chronic pain patients identified in the Swedish Quality Registry for Pain Rehabilitation

BACKGROUND

Chronic pain patients frequently suffer from psychological symptoms. There is no consensus concerning the prevalence of severe anxiety and depressive symptoms and the strength of the associations between pain intensity and psychological distress. Although an important aspect of the clinical picture is understanding how the pain condition impacts life, little is known about the relative importance of pain and psychological symptoms for individual's life impact. The aims of this study were to identify subgroups of pain patients; to analyze if pain, psychological distress, and life impact variables influence subgrouping; and to investigate how patients in the subgroups benefit from treatments.

METHODS

Background variables, pain aspects (intensity/severity and spreading), psychological distress (depressive and anxiety symptoms), and two life impact variables (pain interference and perceived life control) were obtained from the Swedish Quality Registry for Pain Rehabilitation for chronic pain patients and analyzed mainly using advanced multivariate methods.

RESULTS

Based on >35,000 patients, 35%-40% had severe anxiety or depressive symptoms. Severe psychological distress was associated with being born outside Europe (21%-24% vs 6%-8% in the category without psychological distress) and low education level (20.7%-20.8% vs 26%-27% in the category without psychological distress). Dose relationships existed between the two psychological distress variables and pain aspects, but the explained variances were generally low. Pain intensity/severity and the two psychological distress variables were significantly associated (R 2=0.40-0.48; P>0.001) with the two life impact variables (pain interference and life control). Two subgroups of patients were identified at baseline (subgroup 1: n=15,901-16,119; subgroup 2: n=20,690-20,981) and the subgroup with the worst situation regarding all variables participated less in an MMRP (51% vs 58%, P<0.001) but showed the largest improvements in outcomes.

CONCLUSION

The results emphasize the need to assess both pain and psychological distress and not take for granted that pain involves high psychological stress in the individual case. Not all patients benefit from MMRP. A better matching between common clinical pictures and the content of MMRPs may help improve results. We only partly found support for treatment resistance in patients with psychological distress burden.

Evaluating psychosocial contributions to chronic pain outcomes

The biopsychosocial model of pain dominates the scientific community's understanding of chronic pain. Indeed, the biopsychosocial approach describes pain and disability as a multidimensional, dynamic integration among physiological, psychological, and social factors that reciprocally influence one another. In this article, we review two categories of studies that evaluate the contributions of psychosocial factors to the experience of chronic pain. First, we consider general psychosocial variables including distress, trauma, and interpersonal factors. Additionally, we discuss pain-specific psychosocial variables including catastrophizing, expectations, and pain-related coping. Together, we present a diverse array of psychological, social, and contextual factors and highlight the need to consider their roles in the development, maintenance, and treatment of chronic pain conditions.

Prognostic factors of a favorable outcome following a supervised exercise program for soldiers with sub-acute and chronic low back pain

Background

Low back pain (LBP) encompasses heterogeneous patients unlikely to respond to a unique treatment. Identifying sub-groups of LBP may help to improve treatment outcomes. This is a hypothesis-setting study designed to create a clinical prediction rule (CPR) that will predict favorable outcomes in soldiers with sub-acute and chronic LBP participating in a multi-station exercise program.

Methods

Military members with LBP participated in a supervised program comprising 7 stations each consisting of exercises of increasing difficulty. Demographic, impairment and disability data were collected at baseline. The modified Oswestry Disability Index (ODI) was administered at baseline and following the 6-week program. An improvement of 50% in the initial ODI score was considered the reference standard to determine a favorable outcome. Univariate associations with favorable outcome were tested using chi-square or paired t-tests. Variables that showed between-group (favorable/unfavorable) differences were entered into a logistic regression after determining the sampling adequacy. Finally, continuous variables were dichotomized and the sensitivity, specificity and positive and negative likelihood ratios were determined for the model and for each variable.

Results

A sample of 85 participants was included in analyses. Five variables contributed to prediction of a favorable outcome: no pain in lying down (p = 0.017), no use of antidepressants (p = 0.061), FABQ work score < 22.5 (p = 0.061), fewer than 5 physiotherapy sessions before entering the program (p = 0.144) and less than 6 months’ work restriction (p = 0.161). This model yielded a sensitivity of 0.78, specificity of 0.80, LR+ of 3.88, and LR- of 0.28. A 77.5% probability of favorable outcome can be predicted by the presence of more than three of the five variables, while an 80% probability of unfavorable outcome can be expected if only three or fewer variables are present.

Conclusion

The use of prognostic factors may guide clinicians in identifying soldiers with LBP most likely to have a favorable outcome. Further validation studies are needed to determine if the variables identified in our study are treatment effect modifiers that can predict success following participation in the multi-station exercise program.

Trial registration

ClinicalTrials.gov Identifier: NCT03464877 registered retrospectively on 14 March 2018.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2022-x) contains supplementary material, which is available to authorized users.

Pain patients’ experiences of validation and invalidation from physicians before and after multimodal pain rehabilitation: Associations with pain, negative affectivity, and treatment outcome

Background and aims

Validating and invalidating responses play an important role in communication with pain patients, for example regarding emotion regulation and adherence to treatment. However, it is unclear how patients’ perceptions of validation and invalidation relate to patient characteristics and treatment outcome. The aim of this study was to investigate the occurrence of subgroups based on pain patients’ perceptions of validation and invalidation from their physicians. The stability of these perceptions and differences between subgroups regarding pain, pain interference, negative affectivity and treatment outcome were also explored.

Methods

A total of 108 pain patients answered questionnaires regarding perceived validation and invalidation, pain severity, pain interference, and negative affectivity before and after pain rehabilitation treatment. Two cluster analyses using perceived validation and invalidation were performed, one on pre-scores and one on post-scores. The stability of patient perceptions from pre- to post-treatment was investigated, and clusters were compared on pain severity, pain interference, and negative affectivity. Finally, the connection between perceived validation and invalidation and treatment outcome was explored.

Results

Three clusters emerged both before and after treatment: (1) low validation and heightened invalidation, (2) moderate validation and invalidation, and (3) high validation and low invalidation. Perceptions of validation and invalidation were generally stable over time, although there were individuals whose perceptions changed. When compared to the other two clusters, the low validation/heightened invalidation cluster displayed significantly higher levels of pain interference and negative affectivity post-treatment but not pre-treatment. The whole sample significantly improved on pain interference and depression, but treatment outcome was independent of cluster. Unexpectedly, differences between clusters on pain interference and negative affectivity were only found post-treatment. This appeared to be due to the pre- and post-heightened invalidation clusters not containing the same individuals. Therefore, additional analyses were conducted to investigate the individuals who changed clusters. Results showed that patients scoring high on negative affectivity ended up in the heightened invalidation cluster post-treatment.

Conclusions

Taken together, most patients felt understood when communicating with their rehabilitation physician. However, a smaller group of patients experienced the opposite: low levels of validation and heightened levels of invalidation. This group stood out as more problematic, reporting greater pain interference and negative affectivity when compared to the other groups after treatment. Patient perceptions were typically stable over time, but some individuals changed cluster, and these movements seemed to be related to negative affectivity and pain interference. These results do not support a connection between perceived validation and invalidation from physicians (meeting the patients pre- and post-treatment) and treatment outcome. Overall, our results suggest that there is a connection between negative affectivity and pain interference in the patients, and perceived validation and invalidation from the physicians.

Implications

In clinical practice, it is important to pay attention to comorbid psychological problems and level of pain interference, since these factors may negatively influence effective communication. A focus on decreasing invalidating responses and/or increasing validating responses might be particularly important for patients with high levels of psychological problems and pain interference.

Prospective Comparison of Changes in Lumbar Spine MRI Findings over Time between Individuals with Acute Low Back Pain and Controls: An Exploratory Study

BACKGROUND AND PURPOSE

The clinical importance of lumbar MR imaging findings is unclear. This study was an exploratory investigation of whether lumbar spine MR imaging findings change more commonly during a 12-week period in individuals with acute low back pain compared with pain-free controls.

MATERIALS AND METHODS

Twenty individuals with recent-onset low back pain and 10 pain-free controls were recruited into an exploratory prospective cohort study. All participants had a lumbar spine MR imaging at baseline and repeat MR imaging scans at 1, 2, 6, and 12 weeks. The proportion of individuals who had MR imaging findings that changed during the 12-week period was compared with the same proportion in the controls.

RESULTS

In 85% of subjects, we identified a change in at least 1 MR imaging finding during the 12 weeks; however, the proportion was similar in the controls (80%). A change in disc herniation, annular fissure, and nerve root compromise was reported more than twice as commonly in the subjects as in controls (65% versus 30%, 25% versus 10%, and 15% versus 0%, respectively). Caution is required in interpreting these findings due to wide confidence intervals, including no statistical difference. For all other MR imaging findings, the proportions of subjects and controls in whom MR imaging findings were reported to change during 12 weeks were similar.

CONCLUSIONS

Changes in MR imaging findings were observed in a similar proportion of the low back pain and control groups, except for herniations, annular fissures, and nerve root compromise, which were twice as common in subjects with low back pain.

An observational study of the impact of genetic testing for pain perception in the clinical management of chronic non-cancer pain

OBJECTIVE

Pain levels are a key metric in clinical care. However, the assessment of pain is limited to basic questionnaires and physician interpretation, which yield subjective data. Genetic markers of pain sensitivity, such as single nucleotide polymorphisms in the catechol-O-methyltransferase gene, have been shown to be associated with pain perception and have been used to provide objective information about a patient's pain. The goal of this study was to determine if physician treatment adjustments based on genetic tests of pain perception resulted in improved outcomes for patients.

MATERIAL AND METHODS

A prospective, longitudinal study was conducted with 134 chronic non-cancer pain patients genotyped for pain perception-related catechol-O-methyltransferase haplotypes. Physicians were provided with patients' results and asked to document 1) their assessment of benefit of the genetic test; 2) treatment changes made based on the genetic test; and 3) patient clinical responses to changes implemented.

RESULTS

Based on genetic testing results, physicians adjusted treatment plans for 40% of patients. When medication changes were made based on genetic testing results, 72% of patients showed improvement in clinical status. When non-pharmacological actions were performed, 69% of physicians felt their patients' clinical status improved. Moreover, physicians believed the genetic test results were consistent with patient pain levels in 85% of cases.

CONCLUSIONS

These results demonstrate that providing personalized medicine with genetic information related to pain perception affected physician clinical decision-making for a substantial proportion of patients in this study, and that the availability and utilization of this information was a contributing factor in clinical improvement.

Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for "precision medicine" or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

Cell therapy for intervertebral disc repair: Clinical perspective

Low back pain is the main cause of disability and is associated with intervertebral disc degeneration. Contemporary treatments are limited to palliative therapeutics or aggressive surgical interventions; however, current advancements in cell therapy offer to fill this breach. Clinical data suggest that cell transplantation can accomplish pain relief without any observed adverse effects. Despite a large variety of preclinical studies and preliminary clinical investigations, controversy remains on the optimal cell type and transplantation strategies. The translational potential of this article lies in the aim to update on the current state of intervertebral disc cell therapy and to identify current obstacles.

Distinguishing between nociceptive and neuropathic components in chronic low back pain using behavioural evaluation and sensory examination

BACKGROUND

Diagnosis of chronic low back pain (CLBP) is traditionally predicated on identifying underlying pathological or anatomical causes, with treatment outcomes modest at best. Alternately, it is suggested that identification of underlying pain mechanisms with treatments targeted towards specific pain phenotypes may yield more success. Differentiation between nociceptive and neuropathic components of CLBP is problematic; evidence suggests that clinicians fail to identify a significant neuropathic component in many CLBP patients. The painDETECT questionnaire (PDQ) was specifically developed to identify occult but significant neuropathic components in individuals thought to have predominantly nociceptive pain.

METHODS

Using the PDQ, we classified 50 CLBP patients into two distinct groups; those with predominantly nociceptive pain (Group 1) and those with a significant neuropathic component (Group 2). We characterised these two distinct CLBP sub-groups using a) questionnaire-based behavioural evaluation measuring pain-related function and quality of life, pain intensity and psychological well-being and b) sensory examination, using two-point and tactile threshold discrimination.

OBJECTIVE

We sought to determine if differences in the pain phenotype of each CLBP sub-group would be reflected in sensory and behavioural group profiles.

RESULTS

We report that Group 1 and Group 2 sub-groups demonstrate unique clinical profiles with significant differences in sensory tactile discrimination thresholds and in a wide range of behavioural domains measuring pain intensity, disability and psychological well-being.

CONCLUSION

We have demonstrated distinct clinical profiles for CLBP patient sub-groups classified by PDQ. Our results give diagnostic confidence in using the PDQ to characterise two distinct pain phenotypes in a heterogeneous CLBP population.

Rational and design of an individual participant data meta-analysis of spinal manipulative therapy for chronic low back pain-a protocol

BACKGROUND

Chronic low back pain (LBP) is the leading cause of pain and disability, resulting in a major socioeconomic impact. The Cochrane Review which examined the effect of spinal manipulative therapy (SMT) for chronic LBP concluded that SMT is moderately effective, but was based on conventional meta-analysis of aggregate data. The use of individual participant data (IPD) from trials allows for a more precise estimate of the treatment effect and has the potential to identify moderators and/or mediators. The aim is (1) to assess the overall treatment effect of SMT for primary and secondary outcomes in adults with chronic LBP, (2) to determine possible moderation of baseline characteristics on treatment effect, (3) to identify characteristics of intervention (e.g., manipulation/mobilization) that influence the treatment effect, and (4) to identify mediators of treatment effects.

METHODS

All trials included in the Cochrane Review on SMT for chronic LBP will be included which were published after the year 2000, and the search will be updated. No restrictions will be placed on the type of comparison or size of the study. Primary outcomes are pain intensity and physical functioning. A dataset will be compiled consisting of individual trials and variables included according to a predefined coding scheme. Variables to be included are descriptive of characteristics of the study, treatment, comparison, participant characteristics, and outcomes at all follow-up periods. A one-stage approach with a mixed model technique based on the intention-to-treat principle will be used for the analysis. Subsequent analyses will focus on treatment effect moderators and mediators.

DISCUSSION

We will analyze IPD for LBP trials in which SMT is one of the interventions. IPD meta-analysis has been shown to be more reliable and valid than aggregate data meta-analysis, although this difference might also be attributed to the number of studies that can be used or the amount of data that can be utilized. Therefore, this project may identify important gaps in our knowledge with respect to prognostic factors of treatment effects.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015025714.

Characteristics and consequences of the co-occurrence between social anxiety and pain-related fear in chronic pain patients receiving multimodal pain rehabilitation treatment

Background and aims

Chronic pain problems are related to specific pain related fears and maladaptive pain-coping but also commonly co-occur with other anxiety problems. Shared emotional vulnerability factors may explain this comorbidity and may influence treatment outcome. Indeed, pain patients going through multimodal pain treatment are a heterogeneous group and treatment results vary. One understudied anxiety disorder co-occurring with pain is social anxiety. This may be relevant as many pain-related challenges are situated in social contexts. The aim of this study is to investigate the occurrence of subgroups with differential patterns of social anxiety and pain related fear in a sample of chronic pain patients who receive multimodal pain treatment. The aim is also to study the characteristics of these potential subgroups and the consequences of different patterns of social anxiety and pain related fear.

Methods

180 patients with chronic musculoskeletal pain answered questionnaires before and after a multimodal pain treatment in a hospital rehabilitation setting in middle Sweden. A cluster analysis using pre-treatment scores on the Social Phobia Screening Questionnaire and the Tampa Scale of Kinesiophobia was performed. Subgroups were thereafter validated and compared on impairment due to social anxiety, pain catastrophizing, anxiety, and depression. Moreover, subgroups were described and compared on vulnerability factors (anxiety sensitivity, negative affect) and outcome factors (pain intensity, pain interference, and return to work self-efficacy).

Results

Four distinct clusters emerged: (1) low scores, (2) pain-related fear only, (3) social concern only, and (4) high social anxiety and pain-related fear. Patients high on social anxiety and pain-related fear had significantly higher levels of anxiety sensitivity, negative affect, and higher general emotional symptomatology. They also had remaining problems posttreatment.

Conclusions

A subgroup of patients with clinical levels of social anxiety has suboptimal rehabilitation results, with residual emotional problems and high levels of emotional vulnerability.

Implications

These patients may be in need of additional treatment efforts that are not being met today. To prevent insufficient treatment results and prolonged work disability, these patients need to be detected during screening and may benefit from pain treatment that takes their emotional problems into account.

Pain-related distress and clinical depression in chronic pain: A comparison between two measures

Background and purpose

Depression is a frequent co-morbid diagnosis in chronic pain, and has been shown to predict poor outcome. Several reviews have described the difficulty in accurate and appropriate measurement of depression in pain patients, and have proposed a distinction between pain-related distress and clinical depression. Aims of the current study were to compare (a) the overlap and differential categorisation of pain patients as depressed, and (b) the relationship to disability between the Structured Interview for DSM-IV (SCID-Depression module) and the Hospital Anxiety and Depression Scale (HADS-D).

Methods

Seventy-eight chronic back pain patients were administered the SCID-D, the HADS-D and the Pain Disability Index (PDI).

Results

Significantly more patients were categorised with possible and probable depression by the HADS than the SCID-D. Results from Receiver Operating Characteristic (ROC) curve analysis suggested that the HADS-D provided better discriminatory ability to detect disability, demonstrating a better balance between sensitivity and specificity compared to the SCID-D, although a direct comparison between the two measurements showed no difference.

Conclusions

The HADS-D is a reasonably accurate indicator of pain-related distress in chronic pain patients, and captures the link between disability and mood.

Implications

It is likely that the SCID-D is better suited to identifying sub-groups with more pronounced psychiatric disturbance.

Perspective

Several reviews have proposed a distinction between pain-related distress and clinical depression. This study compared the overlap and differential categorisation of pain patients as depressed and the relationship to disability between the Structured Interview for DSM-IV (SCID-D; Depression module) and the Hospital Anxiety and Depression Scale (HADS-D).

© 2016 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Do psychological and behavioral factors classified by the West Haven-Yale Multidimensional Pain Inventory (Swedish version) predict the early clinical course of low back pain in patients receiving chiropractic care?

Background

To investigate if psychological and behavioral factors (as determined by the Swedish version of the West Haven-Yale Multidimensional Pain Inventory, MPI-S) can predict the early clinical course of Low Back Pain (LBP).

Methods

MPI-S data from patients (18–65 years of age) seeking chiropractic care for recurrent and persistent LBP were collected at the 1^st visit. A follow-up questionnaire was administered at the 4^th visit. The predictive value of the MPI-S subgroups Adaptive Copers (AC), Interpersonally Distressed (ID) and Dysfunctional (DYS) was calculated against the subjective improvement at the 4^th visit and clinically relevant difference in pain intensity between the 1^st and 4^th visit.

Results

Of the 666 subjects who were included at the 1^st visit, 329 completed the questionnaire at the 4^th visit. A total of 64.7 % (AC), 68.0 % (ID) and 71.3 % (DYS) reported a definite improvement. The chance of “definite improvement”, expressed as relative risk (95 % CI) with the AC group as reference, was 1.05 (.87–1.27) for the ID and 1.10 (.93–1.31) for the DYS groups, respectively. The DYS and ID groups reported higher values in pain intensity both at the 1^st and the 4^th visit. The proportion of subjects who reported an improvement in pain intensity of 30 % or more (clinically relevant) were 63.5 % AC, 72.0 % ID and 63.2 % DYS. Expressed as relative risk (95 % CI) with the AC group as reference, this corresponded to 1.26 (.91–1.76) for the ID and 1.09 (.78–1.51) for the DYS groups, respectively.

Conclusions

The MPI-S instrument could not predict the early clinical course of recurrent and persistent LBP in this sample of chiropractic patients.

Trial registration

Clinical trials.gov; NCT01539863, February 22, 2012.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-0933-y) contains supplementary material, which is available to authorized users.

Comparative Effectiveness of Conservative Interventions for Nonspecific Chronic Spinal Pain: Physical, Behavioral/Psychologically Informed, or Combined? A Systematic Review and Meta-Analysis

Nonspecific chronic spinal pain (NSCSP) is highly disabling. Current conservative rehabilitation commonly includes physical and behavioral interventions, or a combination of these approaches. Physical interventions aim to enhance physical capacity by using methods such as exercise, manual therapy, and ergonomics. Behavioral/psychologically informed interventions aim to enhance behaviors, cognitions, or mood by using methods such as relaxation and cognitive behavioral therapy. Combined interventions aim to target physical and also behavioral/psychological factors contributing to patients' pain by using methods such as multidisciplinary pain management programs. Because it remains unclear whether any of these approaches are superior, this review aimed to assess the comparative effectiveness of physical, behavioral/psychologically informed, and combined interventions on pain and disability in patients with NSCSP. Ten electronic databases were searched for randomized controlled trials (RCTs) including participants reporting NSCSP. Studies were required to have an "active" conservative treatment control group for comparison. Studies were not eligible if the interventions were from the same domain (eg, if the study compared 2 physical interventions). Study quality was assessed used the Cochrane Back Review Group risk of bias criteria. The treatment effects of physical, behavioral/psychologically informed, and combined interventions were assessed using meta-analyses. Twenty-four studies were included. No clinically significant differences were found for pain and disability between physical, behavioral/psychologically informed, and combined interventions. The simple categorization of interventions into physical, behavioral/psychologically informed, and combined could be considered a limitation of this review, because these interventions may not be easily differentiated to allow accurate comparisons to be made. Further work should consider investigating whether tailoring rehabilitation to individual patients and their perceived risk of chronicity, as seen in recent RCTs for low back pain, can enhance outcomes in NSCSP.

PERSPECTIVE

In this systematic review of RCTs in NSCSP, only small differences in pain or disability were observed between physical, behavioral/psychologically informed, and combined interventions.

Improving performance in golf: current research and implications from a clinical perspective

Golf, a global sport enjoyed by people of all ages and abilities, involves relatively long periods of low intensity exercise interspersed with short bursts of high intensity activity. To meet the physical demands of full swing shots and the mental and physical demands of putting and walking the course, it is frequently recommended that golfers undertake golf-specific exercise programs. Biomechanics, motor learning, and motor control research has increased the understanding of the physical requirements of the game, and using this knowledge, exercise programs aimed at improving golf performance have been developed. However, while it is generally accepted that an exercise program can improve a golfer's physical measurements and some golf performance variables, translating the findings from research into clinical practice to optimise an individual golfer's performance remains challenging. This paper discusses how biomechanical and motor control research has informed current practice and discusses how emerging sophisticated tools and research designs may better assist golfers improve their performance.