Treatment-based subgroups of low back pain: a guide to appraisal of research studies and a summary of current evidence

Patients with worse disability respond best to cognitive functional therapy for chronic low back pain: a pre-planned secondary analysis of a randomised trial

QUESTION

Do five baseline moderators identify patients with chronic low back pain who respond best to cognitive functional therapy (CFT) when compared with usual care?

DESIGN

Secondary analysis of the RESTORE randomised controlled trial.

PARTICIPANTS

A total of 492 adults with low back pain for > 3 months with at least moderate pain-related activity limitation.

INTERVENTION

Participants were allocated to CFT alone or CFT plus biofeedback; these two groups were combined for this secondary analysis. The control group was usual care.

OUTCOME MEASURES

The outcome was activity limitation measured using the Roland Morris Disability Questionnaire (RMDQ) at 3, 6, 13, 26, 40 and 52 weeks. Investigated effect modifiers were baseline measures of activity limitation, cognitive flexibility, pain intensity, self-efficacy and catastrophising.

RESULTS

Baseline levels of activity limitation and, potentially, cognitive flexibility were associated with different effects of CFT treatment, while pain intensity, self-efficacy and catastrophising were not. Patients who had higher baseline activity limitation had greater treatment effects at 13 and 52 weeks. A person with a baseline RMDQ score of 18 (90th percentile) would on average be 6.1 (95% CI 4.8 to 7.4) points better at 13 weeks if they received CFT compared with usual care. However, a person with a baseline score of 7 (10th percentile) would on average be 3.6 (95% CI 2.6 to 4.6) points better at 13 weeks.

CONCLUSION

The finding that CFT is most effective among patients who are most disabled and incur the greatest burden strongly suggests that CFT should be considered as a treatment for this group of patients.

REGISTRATION

ACTRN12618001396213.

The difference in multifidus muscle morphology and motor control in non-specific low back pain with clinical lumbar instability and healthy subjects: A case-control study

BACKGROUND

Low back pain (LBP) with clinical lumbar instability (CLI) is considered a subgroup of back pain. Poor core stability function and/or lack of motor controls are thought to play a role in inappropriate inter-segmental movements and pain. There is no study investigating the changes in the lumbar multifidus muscle (LMM) morphology and motor control in this subgroup of patients.

OBJECTIVE

To assess motor control components and morphological changes of LMM in the patients suffering from chronic nonspecific low back pain (CNSLBP) with CLI.

DESIGN

Observational case-control study.

METHODS

Thirty-two patients suffering from (CNSLBP) with CLI and 32 healthy individuals were included. The muscle force element of lumbar motor control was assessed by using (the active straight-leg raise test, leg lowering test, and Trendelenburg test). Ultrasonography was used to assess changes in the LMM morphology.

RESULTS

There was a significant decrease in motor control (p = 0.0001), an increase in LMM fatty infiltration (p = 0.002), and a decrease in the thickness of LMM in patients suffering from CNSLBP during contraction (p = 0.006), during rest (p = 0.018). The cross-section area of the LMM showed no statistically significant differences during rest on the right and left sides (p = 0.827, 0.220 respectively) and contraction (p = 0.160, 0.278 respectively) between patients and healthy subjects.

CONCLUSION

Motor control and the morphology of LMM in patients with CNSLBP with CLI may provide insight into the mechanisms of underlying pain and their effect on muscle function and structure.

Patient profiling and outcome assessment in spinal cord stimulation for chronic back and/or leg pain (the PROSTIM study): a study protocol

Spinal cord stimulation (SCS) is a well-established treatment option in the multidisciplinary approach to chronic back and leg pain. Nevertheless, careful patient selection remains crucial to provide the most optimal treatment and prevent treatment failure. We report the protocol for the PROSTIM study, an ongoing prospective, multicentric and observational clinical study (NCT05349695) that aims to identify different patient clusters and their outcomes after SCS. Patients are recruited in different centers in Europe. Analysis focuses on identifying significant patient clusters based on different health domains and the changes in biopsychosocial variables 6 weeks, 3 and 12 months after implantation. This study is the first to include a biopsychosocial cluster analysis to identify significant patient groups and their response to treatment with SCS.

A model for personalized diagnostics for non-specific low back pain: the role of the myofascial unit

Low back pain (LBP) is the leading cause of disability worldwide. Most LBP is non-specific or idiopathic, which is defined as symptoms of unknown origin without a clear specific cause or pathology. Current guidelines for clinical evaluation are based on ruling out underlying serious medical conditions, but not on addressing underlying potential contributors to pain. Although efforts have been made to identify subgroups within this population based on response to treatment, a comprehensive framework to guide assessment is still lacking. In this paper, we propose a model for a personalized mechanism-based assessment based on the available evidence that seeks to identify the underlying pathologies that may initiate and perpetuate central sensitization associated with chronic non-specific low back pain (nsLBP). We propose that central sensitization can have downstream effects on the "myofascial unit", defined as an integrated anatomical and functional structure that includes muscle fibers, fascia (including endomysium, perimysium and epimysium) and its associated innervations (free nerve endings, muscle spindles), lymphatics, and blood vessels. The tissue-level abnormalities can be perpetuated through a vicious cycle of neurogenic inflammation, impaired fascial gliding, and interstitial inflammatory stasis that manifest as the clinical findings for nsLBP. We postulate that our proposed model offers biological plausibility for the complex spectrum of clinical findings, including tissue-level abnormalities, biomechanical dysfunction and postural asymmetry, ecological and psychosocial factors, associated with nsLBP. The model suggests a multi-domain evaluation that is personalized, feasible and helps rule out specific causes for back pain guiding clinically relevant management. It may also provide a roadmap for future research to elucidate mechanisms underlying this ubiquitous and complex problem.

Classifying patients with non-specific chronic low back pain using the impact stratification score in an online convenience sample

BACKGROUND

In 2014, the National Institute of Health Pain Consortium's research task force (RTF) on research standards for chronic low back pain (CLBP) proposed the Impact Stratification Score (ISS) as a patient-reported outcome measure that could stratify patients by the impact CLBP has on their lives. This work compares three newly developed ISS-based classifications to the RTF's original to provide an optimal recommendation.

METHODS

The online sample included 1226 individuals from Amazon's Mechanical Turk who indicated having non-specific CLBP, average age of 40, 49% female, and 67% White. Participants completed the PROMIS-29 v2.1 profile survey that contains the 9 ISS items as well the Roland-Morris Disability Questionnaire (RMDQ) and Graded Chronic Pain Scale (GCPS). Other items included high-impact chronic pain; not working due to health problems; overall health; and number of healthcare visits for back pain in the past 6 months. Three new classifications were created using quartiles (Classification 2), latent profile analysis (Classification 3), and one modeled after the GCPS (Classification 4). Classifications were subsequently compared to the RTF-proposed classification (Classification 1) on several concurrent and prognostic criteria.

RESULTS

Classification 1 had three CLBP severity groups, four in Classification 2, three in Classification 3, and four in Classification 4. All novel classifications improved upon the original. Classification 2 performed best at minimizing the classification of those with negative outcomes into the lowest severity groups at baseline (e.g., 11% with RMDQ ≥ 7) and 6 months (e.g., 8.2% had fair/poor health). Classification 4 performed best at maximizing classification of those with negative outcomes into the most severe group concurrently (e.g., 100% had GCPS grade ≥ 2) and at 6 months (e.g., 100% with RMDQ ≥ 7).

CONCLUSIONS

We developed three ISS-based classification schemes and tested them against several outcomes. All three improved upon the original scheme. While appearing more optimal than other classifications in the lowest severity groups, Classification 2 presents some considerations and limitations. Given that Classification 4 was an improvement at the lowest end of severity and was the best at the highest end, it is our tentative recommendation that this approach be adopted to classify individuals with non-specific CLBP.

Interoceptive anxiety-related processes: Importance for understanding COVID-19 and future pandemic mental health and addictive behaviors and their comorbidity

The COVID-19 pandemic is associated with an increased prevalence of mental health problems and addictive behaviors. There is a growing theoretical and empirical evidence that individual differences in interoceptive anxiety-related processes are a one set of vulnerability factors that are important in understanding the impact of pandemic-related mental health problems and addictive behavior. However, there has not been a comprehensive effort to explore this rapidly growing body of research and its implications for public health. In this paper, we discuss why interoceptive anxiety-related processes are relevant to understanding mental health and addictive behaviors during the COVID-19 pandemic. We then provide a narrative review of the available COVID-19 literature linking interoceptive fear and anxiety-related processes (e.g., anxiety sensitivity, health anxiety, and COVID-19 anxiety, fear, and worry) to mental health and addictive behaviors. We then propose a novel transdiagnostic theoretical model that highlights the role of interoceptive anxiety-related processes in mental health and addictive behavior in the context of the present and future pandemics. In the final section, we utilize this conceptualization to underscore clinical implications and provide guidance for future research initiatives in the management of COVID-19 mental health and addictive behaviors and inform the public health field for future pandemics.

A novel (targeted) kinesio taping application on chronic low back pain: Randomized clinical trial

The aim of the present clinical trial is to evaluate the efficacy of kinesio taping on patients with chronic low back pain, when the exploration identifies skin/fascia mobilization as a factor that could modify the treatment effect. This study is a randomized controlled trial with intention-to-treat analysis. Sixty-two participants with chronic low back pain were therefore recruited from a tertiary referral hospital. Targeted kinesio taping, according to skin/fascia mobility exploration, was applied in the experimental group (17 female/13 male; 49.47 ± 11.15 years) once a week for four sessions. The control group (17 female/14 male; 48.87 ± 9.09 years) underwent a placebo taping application. At post-treatment time there was a statistically significant reduction both in disability (Roland-Morris Disability Questionnaire) and pain (Numeric Pain Rating Scale) in the experimental group (disability: -2.88, 95% confidence interval [CI] -4.56 to -1.21, P < .001; pain: -1.58, 95% CI -2.67 to -0.54 P = .001) and the control group (disability: -1.82, 95% CI -3.46 to -0.17 P = .025; pain: -1.30, 95% CI -2.32 to -0.28 P = .008). However, at six months, these changes only remained significant in the experimental group (disability: -2.95, 95% CI -4.72 to -1.18, P < .001; pain: -1.06, 95% CI -2.07 to -0.04, P < .05). As a conclusion, the application of targeted kinesio taping produced a significant reduction in pain and disability, at 4 weeks and at 6 moths follow-up, although there were no differences between groups at any measurement time point.

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

INTRODUCTION

The Multidimensional Pain Inventory (MPI) is frequently used in the assessment of chronic pain. Three subgroups have been derived from MPI: adaptive coper (AC), dysfunctional (DYS), and interpersonally distressed (ID). The primary aim of this study was to examine whether outcome of Interdisciplinary Multimodal Pain Rehabilitation Programs (IMMRPs) differed across the MPI subgroups.

METHODS

Patients with chronic pain (N = 34,513), included in the Swedish Quality Registry for Pain Rehabilitation, were classified into MPI subgroups and a subset that participated in IMMRPs (N = 13,419) was used to examine overall treatment outcomes using a previously established Multivariate Improvement Score (MIS) and 2 retrospective patient-evaluated benefits from treatment.

RESULTS

The subgroups differed on sociodemographic characteristics, pain duration, and spatial spreading of pain. DYS and ID had the best overall outcomes to MIS. AC had the best outcomes according to the 2 retrospective items. Transition into other subgroups following IMMRP was common and most prominent in DYS and least prominent in AC.

CONCLUSION

The validity of the MPI subgroups was partially confirmed. DYS and ID had the most severe clinical presentations at baseline and showed most improvement following IMMRP, but overall severity in DYS and ID at post-treatment was still higher than in the AC group. Future studies should examine how processes captured by MPI interact with neurobiological, medical, sociodemographic, and adaptation/coping factors and how these interactions impact severity of chronic pain and treatment outcome.

A directional preference approach for chronic pelvic pain, bladder dysfunction and concurrent musculoskeletal symptoms: a case series

BACKGROUND

Chronic pelvic pain (CPP) with concurrent musculoskeletal and bladder symptoms is a complex and challenging problem. However, clinically the co-existence of these symptoms is not routinely questioned, and their musculoskeletal source is not investigated thoroughly. The purpose of this case series is to present the use of Mechanical Diagnosis and Therapy (MDT) principles in seven patients with concurrent chronic pelvic pain, bladder dysfunction and musculoskeletal symptoms.

CASE DESCRIPTIONS

Seven patients with coexisting pelvic health and musculoskeletal signs and symptoms were retrospectively reviewed. Most common symptoms were urinary frequency, incontinence, pelvic pain, nocturia, dyspareunia, bladder dyssynergia, and lumbar, pelvic or hip pain. All patients failed to recognize the possible interconnectedness of the two sets of symptoms. Each exhibited a directional preference (DP) and subsequent MDT provisional classification of derangement was established; the use of DP forces abolished or dramatically improved both symptoms and mobility impairments. In all cases DP was for sustained sagittal forces initially, but ultimately lateral forces and mobilization were indicated.

OUTCOMES

Changes in Pelvic Floor Impact Questionnaire, Care Connections Pelvic Floor and Lumbar spine were all clinically significant and exceeded minimally Clinical Important Differences several times. Average of 5.8 sessions per patient was noted. Follow-up at an average of 3.3 years revealed ongoing satisfaction and confidence in independent self-management.

DISCUSSION

These case studies highlight the importance of ensuring expansion of intake questions for possible co-existence of symptoms in both pelvic and musculoskeletal patients, possibly suggesting a mechanical intervention is indicated. Provisional subclassification into 'Mechanical Pelvic Syndrome' is proposed. Level of Evidence: 4.

Baseline characteristics did not identify people with low back pain who respond best to a Movement System Impairment-Based classification treatment

STUDY DESIGN

Secondary analysis of data from a randomized controlled trial.

BACKGROUND

Treatment based on the Movement System Impairment-Based classification for chronic low back pain results in the same benefit when compared to other forms of exercise. It is possible that participant's characteristics measured at baseline can identify people with chronic low back pain who would respond best to a treatment based on the Movement System Impairment model.

OBJECTIVES

To assess if specific characteristics of people with chronic low back pain measured at baseline can modify the effects of a treatment based on the Movement System Impairment model on pain and disability.

METHODS

Four variables assessed at baseline that could potentially modify the treatment effects of the treatment based on the Movement System Impairment model were selected (age, educational status, physical activity status and STarT back tool classification). Separate univariate models were used to investigate a possible modifier treatment effect of baseline participant's characteristics on pain and disability after the treatment. Findings of interaction values above 1 point for the outcome mean pain intensity or above 3 points for disability (Roland Morris questionnaire) were considered clinically relevant.

RESULTS

Linear regression analyses for the outcomes of pain and disability did not show interaction values considered clinically relevant for age, educational status, physical activity status and STarT back tool classification.

CONCLUSION

Age, educational status, physical activity status and STarT back tool classification did not modify the effects of an 8-week treatment based on the Movement System Impairment model in patients with chronic low back pain. Registered at www.clinicaltrials.gov: NCT02221609 (https://clinicaltrials.gov/ct2/show/NCT02221609).

Family History Influences the Effectiveness of Home Exercise in Older People With Chronic Low Back Pain: A Secondary Analysis of a Randomized Controlled Trial

OBJECTIVE

To investigate whether a family history of low back pain (LBP) influences patient outcomes and treatment effects following home exercises in older people with chronic LBP.

DESIGN

Secondary analysis of a randomized controlled trial.

SETTING

Local community.

PARTICIPANTS

People older than 55 years with chronic LBP (N=60).

INTERVENTIONS

Participants in the intervention group completed video game exercises for 60 minutes 3 times per week for 8 weeks. Participants in the control group were instructed to maintain their usual levels of activity and care seeking behaviors.

MAIN OUTCOMES MEASURES

Participants indicated whether any of their immediate family members had a history of "any" LBP or "activity-limiting" LBP at baseline. We collected self-reported measures of pain, function, pain self-efficacy, care seeking, physical activity, disability, fear of movement and/or reinjury, and falls efficacy at baseline, 8 weeks, 3 months, and 6 months. We performed regression analyses to determine whether a family history of LBP predicted patient outcomes and moderated the effects of home exercise.

RESULTS

Participants with a family history of any LBP were less likely to be highly active than those without a family history (odds ratio, 0.08; 95% CI, 0.01-0.42; P=.003). Home-based video game exercises led to improvements in function in those without a family history of activity-limiting LBP (β=1.78; 95% CI, 0.56-3.00; P=.006) but not in those with a family history (β=-0.17; 95% CI, -2.56 to 2.21; P=.880) (interaction P=.049). A family history of LBP did not influence the remaining patient outcomes or treatment effects.

CONCLUSIONS

A family history of LBP appears to negatively influence physical activity levels in older people with chronic LBP. Further, home-based video game exercises appear to be beneficial for older people with chronic LBP that do not have a family history of LBP.

Exercise, headache, and factors associated with headache in chronic whiplash: Analysis of a randomized clinical trial

BACKGROUND

Almost 40% of individuals with chronic whiplash-associated disorders (WAD) report headache after 5 years, making it one of the most common persistent symptoms besides neck pain, but randomized treatment studies are lacking. This study aimed to evaluate the effect of 3 different exercise approaches on headache in chronic WAD grades 2 and 3, and to identify potential factors associated with such headache, and whether they differ depending on 3 different aspects of such headache (current headache, maximum headache, or headache bothersomeness).

METHODS

This was an analysis of a randomized clinical trial of people with chronic WAD and headache (n = 188), who were randomized to either 12 weeks of neck-specific exercise without (NSE) or with a behavioral approach (NSEB) or physical activity prescription (PPA). Data were collected at baseline and at 3, 6, and 12 months. Physical and psychosocial factors were tested for association with headache. Multivariate regression models and linear mixed models were used.

RESULTS

The NSE/NSEB groups reported reduced headache both over time and compared to PPA. Up to 51% (NSE) and 61% (NSEB) reported at least 50% reduction in their headache at 12 months. The PPA group was not improved over time. Neck pain and dizziness were associated with headache regardless of aspect of headache. The only associated psychosocial factor was anxiety, which was associated with headache bothersomeness. Other factors were mainly physical, and up to 51% of the variance was explained.

CONCLUSION

Headache in chronic WAD, may be reduced with neck-specific exercise with or without a behavioral approach. Chronic headache was associated with neck pain and dizziness regardless of aspect tested. Other factors associated with headache in chronic WAD were mainly physical rather than psychosocial.

TRIAL REGISTRATION NUMBER

Clinical Trials.gov, no: NCT015285.

The Evolving Case Supporting Individualised Physiotherapy for Low Back Pain

Low-back pain (LBP) is one of the most burdensome health problems in the world. Guidelines recommend simple treatments such as advice that may result in suboptimal outcomes, particularly when applied to people with complex biopsychosocial barriers to recovery. Individualised physiotherapy has the potential of being more effective for people with LBP; however, there is limited evidence supporting this approach. A series of studies supporting the mechanisms underpinning and effectiveness of the Specific Treatment of Problems of the Spine (STOPS) approach to individualised physiotherapy have been published. The clinical and research implications of these findings are presented and discussed. Treatment based on the STOPS approach should also be considered as an approach to individualised physiotherapy in people with LBP.

Psychosocial and behavioural characteristics in women with pregnancy-related lumbopelvic pain 12 years postpartum

Background

There is insufficient evidence regarding psychosocial factors and its long-term association with persistent pregnancy-related lumbopelvic pain. The overall aim of this study was to investigate women with persistent pregnancy-related lumbopelvic pain 12 years postpartum based on psychosocial and behavioural characteristics using the Swedish version of the Multidimensional Pain Inventory (MPI-S) classification system.

Material and methods

This is a cross-sectional study based on a previous cohort. Data collection took place through a questionnaire. A total of 295 women from the initial cohort (n = 639) responded to the questionnaire giving a response rate of 47.3%. To determine the relative risk (RR) of reporting pain 12 years postpartum, a robust modified Poisson regression was used. This is the first study using the MPI-S as a predictive variable on women with persistent pregnancy-related lumbopelvic pain.

Results

The MPI-S classification procedure was carried out on a total of n = 226 women, where 53 women were classified as interpersonally distressed (ID), 82 as dysfunctional (DYS), and 91 as adaptive copers (AC). Women in the ID and DYS subgroups had a relative risk (RR) of reporting persistent pregnancy-related lumbopelvic pain 12 years postpartum that was more than twice as high compared to the AC subgroup (95% confidence interval (CI) in parenthesis): RR 2.57 (CI 1.76 - 3.75), p<0.0001 and RR 2.23 (CI 1.53 - 3.25), p<0.0001 respectively. Women in the DYS subgroup had more than 5 times increased risk of reporting sick leave the past 12 months compared to the AC subgroup (RR 5.44; CI 1.70 - 17.38, p=0.004).

Conclusions

The present study demonstrates that it is possible to classify women with persistent pregnancy-related lumbopelvic pain 12 years postpartum into relevant clinical subgroups based on psychosocial and behavioural characteristics using the MPI-S questionnaire.

Chronic low back pain is highly individualised: patterns of classification across three unidimensional subgrouping analyses

BACKGROUND AND AIMS

Chronic low back pain (CLBP) is a complex disorder where central and peripheral nociceptive processes are influenced by factors from multiple dimensions associated with CLBP (e.g. movement, pain sensitivity, psychological). To date, outcomes for treatments matched to unidimensional subgroups (e.g. psychologically-based) have been poor. Therefore, unidimensional subgrouping may not reflect the complexity of CLBP presentations at an individual level. The aim of this study was therefore to explore patterns of classification at an individual level across the three previously-published, data-driven, within-dimension subgrouping studies.

METHODS

Cross-sectional, multidimensional data was collected in 294 people with CLBP. Statistical derivation of subgroups within each of three clinically-important dimensions (pain sensitivity, psychological profile, pain responses following repeated spinal bending) was briefly reviewed. Patterns of classification membership were subsequently tabulated across the three dimensions.

RESULTS

Of 27 possible patterns across these dimensions, 26 were represented across the cohort.

CONCLUSIONS

This result highlights that while unidimensional subgrouping has been thought useful to guide treatment, it is unlikely to capture the full complexity of CLBP. The amount of complexity important for best patient outcomes is currently untested.

IMPLICATIONS

For clinicians this study highlights the high variability of presentations of people with CLBP at the level of the individual. For example, clinician's should not assume that those with high levels of pain sensitivity will also have high psychological distress and have pain summation following repeated spinal bending. A more flexible, multidimensional, clinically-reasoned approach to profile patient complexity may be required to inform individualised, patient-centred care. Such individualised care might improve treatment efficacy. This study also has implications for researchers; highlighting the inadequacy of unidimensional subgrouping processes and methodological difficulties in deriving subgroups across multidimensional data.

Can Biomechanics Research Lead to More Effective Treatment of Low Back Pain? A Point-Counterpoint Debate

SYNOPSIS

Although biomechanics plays a role in the development and perhaps the persistent or recurrent nature of low back pain (LBP), whether biomechanics alone can provide the basis for intervention is debated. Biomechanics, which refers to the mechanics of the body, including its neuromuscular control, has been studied extensively in LBP. But, can gains be made in understanding LBP by research focused on this component of biology in the multifactorial biopsychosocial problem of LBP? This commentary considers whether biomechanics research has the potential to advance treatment of LBP, and how likely it is that this research will lead to better treatment strategies. A point-counterpoint format is taken to present both sides of the argument. First, the challenges faced by an approach that considers biomechanics in isolation are presented. Next, we describe 3 models that place substantial emphasis on biomechanical factors. Finally, reactions to each point are presented as a foundation for further research and clinical practice to progress understanding of the place for biomechanics in guiding treatment of LBP. J Orthop Sports Phys Ther 2019;49(6):425-436. Epub 15 May 2019. doi:10.2519/jospt.2019.8825.

Model Simulations Challenge Reductionist Research Approaches to Studying Chronic Low Back Pain

BACKGROUND

Traditionally, low back pain (LBP) is studied using a reductionist approach, in which the factors contributing to the clinical presentation of LBP are studied in isolation to identify the primary pathology or condition linked to LBP. We argue that reductionism may not be suitable for studying LBP, considering the complex, multifactorial nature of this condition.

OBJECTIVES

To quantify the likelihood of successfully subclassifying patients with LBP and effectively targeting treatment based on a single dominant factor contributing to LBP.

METHODS

Both analytical and numerical simulations (Monte Carlo) of 1 million patients with LBP were performed. Several factors contributing to LBP were randomly assigned to each individual. The following outcome measures were computed, as a function of the number of factors: the percentage of individuals who could be subclassified by identifying a single factor exceeding a certain threshold, and the average reduction in LBP when treatment eliminates the largest contributing factor versus a multimodal treatment that eliminates a number of the randomly selected factors.

RESULTS

With an increasing number of factors, the probability of subclassifying an individual to a subgroup based on a single factor tends toward zero. A multimodal treatment arbitrarily addressing any 2 or more factors was more effective than diagnosing and treating a single factor that maximally contributed to LBP.

CONCLUSION

Results suggest that reductionism is not appropriate for subclassifying patients with LBP or for targeting treatment. The use of reductionist approaches may explain some of the challenges when creating LBP classification systems and designing effective treatment interventions. J Orthop Sports Phys Ther 2019;49(6):477-481. Epub 15 May 2019. doi:10.2519/jospt.2019.8791.

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.

Effects of spinal manipulative therapy biomechanical parameters on clinical and biomechanical outcomes of participants with chronic thoracic pain: a randomized controlled experimental trial

BACKGROUND

Spinal manipulative therapy (SMT) includes biomechanical parameters that vary between clinicians, but for which the influence on the therapy clinical effects is unknown. This parallel-randomized controlled trial aimed to investigate the effect of SMT biomechanical parameters on the outcomes of participants with chronic thoracic pain (CTP) following three treatment sessions (follow-up at one week).

METHODS

Adults reporting CTP (pain within the evaluated region [T6 to T8] for ≥3 months) were asked to participate in a four-session trial. At the first session, participants were randomly assigned to one of three experimental groups (different SMT doses) or the control group (no SMT). During the first three sessions, one SMT was executed at T7 for the experimental groups, while a 5-min rest was provided to the control group. SMT were delivered through an apparatus using a servo-controlled linear actuator motor and doses consisted of peak forces, impulse durations, and rates of force application set at 135 N, 125 ms and 920 N/s (group 1), at 250 N, 125 ms and 1840 N/s (group 2), and at 250 N, 250 ms, 920 N/s (group 3). Disability and pain intensity were evaluated at each session (primary outcomes). Spinal stiffness was assessed before-and-after each SMT/rest and at follow-up. Tenderness and muscle activity were evaluated during each spinal stiffness trial. Improvement was evaluated at follow-up. Differences in outcomes between groups and sessions were evaluated as well as factors associated with clinical improvement.

RESULTS

Eighty-one participants were recruited and 17, 20, 20 participants of the three experimental groups and 18 of the control group completed the protocol. In exception of higher pain intensity at baseline in the control group, no between-group differences were found for any of the outcomes. A decrease in pain intensity, disability, spinal stiffness, and tenderness during spinal stiffness were observed (p-values< 0.05). At follow-up, 24% of participants were classified as 'improved'. Predictors of improvement were a greater decrease in pain intensity and in tenderness (p-values< 0.05).

CONCLUSIONS

In an experimental setting, the delivery of a SMT does not lead to significantly different outcomes in participants with CTP than a control condition (spinal stiffness assessment). Studies are still required to explore the mechanisms underlying SMT effects.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03063177 , registered 24 February 2017).

Clinimetric Testing of the Lumbar Spine Instability Questionnaire

BACKGROUND

The Lumbar Spine Instability Questionnaire (LSIQ) is a self-report measure of 15 items. Previous studies have used the LSIQ as a measure of clinical instability; however, a comprehensive evaluation of its clinimetric properties has not been conducted.

OBJECTIVES

The aim of this study was to evaluate the clinimetric properties of the LSIQ in patients with chronic nonspecific low back pain (LBP).

METHODS

In this clinical measurement study, the authors included patients with nonspecific LBP presenting to primary care clinicians in Australia. Rasch analysis was conducted to assess item hierarchy, targeting, unidimensionality, person fit, internal consistency, and differential item functioning. The researchers assessed test-retest reliability of total scores and individual item scores, as well as convergent and divergent validity.

RESULTS

A total of 107 participants with LBP (60 men and 47 women) were recruited. The results were variable. The LSIQ appeared to constitute a unidimensional measure, targeted the sample well, and showed adequate test-retest reliability. However, the scale had poor internal consistency, did not appear to function as an interval-level measure, and had unclear construct validity. Although no items appeared to be redundant, several items were biased by factors other than the proposed construct of the measure.

CONCLUSION

The LSIQ does not seem to be ready to be implemented in clinical practice and may require theoretical reconsideration. Although the LSIQ provided satisfactory estimates for some clinimetric features, the authors do not consider the instrument to be useful as an interval-level measure but rather as an index. Future studies are needed to investigate whether the LSIQ could measure clinical instability or some other construct. J Orthop Sports Phys Ther 2018;48(12):915-922. Epub 22 Jun 2018. doi:10.2519/jospt.2018.7866.

Can patient-reported profiles avoid unnecessary referral to a spine surgeon? An observational study to further develop the Nijmegen Decision Tool for Chronic Low Back Pain

INTRODUCTION

Chronic Low Back Pain (CLBP) is a heterogeneous condition with lack of diagnostic clarity. Therapeutic interventions show small effects. To improve outcomes by targeting interventions it is recommended to develop a triage system to surgical and non-surgical treatments based on treatment outcomes. The objective of the current study was to develop and internally validate prognostic models based on pre-treatment patient-reported profiles that identify patients who either respond or do not respond to two frequently performed treatments (lumbar spine surgery and multidisciplinary pain management program).

METHODS

A consecutive cohort study in a secondary referral spine center was performed. The study followed the recommendations of the PROGRESS framework and was registered in the Dutch Trial Register (NTR5946). Data of forty-seven potential pre-consultation (baseline) indicators predicting 'response' or 'non-response' at one-year follow-up for the two treatments were obtained to develop and validate four multivariable logistic regression models. The source population consisted of 3,410 referred CLBP-patients. Two treatment cohorts were defined: elective 'spine surgery' (n = 217 [6.4%]) and multidisciplinary bio-psychosocial 'pain management program' (n = 171 [5.0%]). Main inclusion criteria were age ≥18, CLBP (≥6 months), and not responding to primary care treatment. The primary outcome was functional ability: 'response' (Oswestry Disability Index [ODI] ≤22) and 'non-response' (ODI ≥41).

RESULTS

Baseline indicators predictive of treatment outcome were: degree of disability (all models), ≥2 previous spine surgeries, psychosocial complaints, age (onset <20 or >50), and patient expectations of treatment outcomes. The explained variances were low for the models predicting response and non-response to pain management program (R2 respectively 23% and 26%) and modest for surgery (R2 30% and 39%). The overall performance was acceptable (c-index; 0.72-0.83), the model predicting non-response to surgery performed best (R2 = 39%; c-index = 0.83).

CONCLUSION

This study was the first to identify different patient-reported profiles that predict response to different treatments for CLBP. The model predicting 'non-response' to elective lumbar spine surgery performed remarkably well, suggesting that referrals of these patients to a spine surgeon could be avoided. After external validation, the patient-reported profiles could potentially enhance timely patient triage to the right secondary care specialist and improve decision-making between clinican and patient. This could lead to improved treatment outcomes, which results in a more efficient use of healthcare resources.

A new clinical model for facilitating the development of pattern recognition skills in clinical pain assessment

Common, enigmatic musculoskeletal conditions such as whiplash-associated disorder, myofascial pain syndrome, low back pain, headache, fibromyalgia, osteoarthritis, and rotator cuff pathology, account for significant social, economic, and personal burdens on a global scale. Despite their primacy (and shared sequelae) there remains a paucity of available and effective management options for patients with both acute and chronic conditions. Establishing an accurate prognostic or diagnostic profile on a patient-by-patient basis can challenge the insight of both novice and expert clinicians. Questions remain on how and when to choose the right tool(s), at the right time(s), for the right patient(s), for the right problem(s). The aim of this paper is to introduce a new clinical reasoning framework that is simple in presentation but allows interpretation of complex clinical patterns, and is adaptable across patient populations with acute or chronic, traumatic or non-traumatic pain. The concepts of clinical phenotyping (e.g. identifying observable characteristics of an individual resulting from the interaction of his/her genotype and their environment) and triangulation serve as the foundation for this framework. Based on our own clinical and research programs, we present these concepts using two patient cases; a) whiplash-associated disorder (WAD) following a motor vehicle collision and b) mechanical low back pain.

Clinical Manifestation of Acute, Subacute, and Chronic Low Back Pain in Different Age Groups: Low Back Pain in 35,446 Patients

BACKGROUND

Low back pain (LBP) is a major healthcare problem causing tremendous economic costs.

METHODS

Clinical manifestation of LBP was characterized in 35,446 patients. We focused on the comparison of the acute, subacute, and chronic LBP stage with regard to patients' ages, based on epidemiologic and clinical questionnaires (eg, painDETECT Questionnaire, Pain Disability Index), pain intensity, pain descriptors, and functional impairment.

RESULTS

We found that neuropathic components were most frequent in chronic LBP patients at the ages of 51 to 60 years. Elderly LBP patients showed a decrease in neuropathic and an increase in nociceptive pain. The most frequently reported pain descriptors were "pressure pain" and "pain attacks" through all stages of LBP, whereas "burning" and "prickling" were most frequent in the chronic stage. Patients after back surgery presented neuropathic pain symptoms most frequently and had the highest amount of pain medication intake.

CONCLUSIONS

Burning and prickling were revealed as possible indicators for LBP chronicity. Combined with pain attacks and pressure pain, these 4 pain descriptors might be a promising adjunct to pain intensity in terms of outcome parameters for future LBP studies. The decrease of neuropathic pain syndromes in the elderly might be explained by degenerative processes. The presented work provides important insights on LBP management in the acute, subacute, and chronic stages.

Spinal manipulation plus laser therapy versus laser therapy alone in the treatment of chronic non-specific low back pain: a randomized controlled study

BACKGROUND

Low back pain (LBP) is a common musculoskeletal disorder causing pain and disability in most of the countries. In recent years, new approaches such as Spinal manipulation and laser therapy have been considered as an alternative to conventional exercise and also found contradicting results in terms of its effectiveness.

AIM

A study to compare the combined effects of spinal manipulation, Laser and exercise versus Laser and exercise alone in chronic non-specific low back pain (cnLBP).

DESIGN

Randomized control study.

SETTING

Subjects with cnLBP were treated with spinal manipulation, Laser and exercise in outpatient department for four weeks.

POPULATION

Three hundred and thirty subjects who fulfilled the selection criteria were randomized (1:1:1 ratio) into SM-LT-CE (N.=110), LT-CE (N.=110) and control group (N.=110).

METHODS

The outcome measurements were Visual Analog Scale (VAS), Modified Modified Schober Test (MMST) Roland and Morris Disability Questionnaire (RMDQ), Physical Health Questionnaire-9 (PHQ-9) and Health Related Quality of Life-4 (HRQOL-4). Baseline and follow-up measurements were measured at 4 weeks, 6 and 12 months by a blinded investigator.

RESULTS

Three hundred and twenty-six subjects completed the intervention and 304 completed the 12-month follow-up. Demographic variables show homogeneity between the groups and ANOVA analyses showed significant improvement (P<0.001) in pain reduction (VAS), flexion range of motion (MMST), functional disability (RMDQ), depression status (PHQ-9), and quality of life (HRQOL-4) in SM-LT-CE group compared to the other two groups at one-year follow-up.

CONCLUSIONS

Spinal manipulation combined with laser therapy and conventional exercise is more effective than laser therapy and conventional exercise alone in chronic non-specific low back pain.

CLINICAL REHABILITATION IMPACT

Spinal manipulation is an adjuvant intervention and it can be applied in every day clinical practice.

Pharmacotherapy for chronic non-specific low back pain: current and future options

INTRODUCTION

Low back pain is associated with a large burden-of-illness. It is responsible for the most years lived with disability as compared with any other medical condition. A comprehensive overview of the evidence on pharmacological treatment options for chronic low back pain is lacking. This review evaluates the evidence for the benefits and risks of currently available pharmacological treatments for chronic low back pain.

AREAS COVERED

The authors focus on the recent (Cochrane) systematic reviews and meta-analyses of randomized clinical trials covering paracetamol (acetaminophen), NSAIDs, muscle relaxants, antidepressants, anticonvulsants, opioids, and other (new) drugs.

EXPERT OPINION

The overall impression of the efficacy of pharmacological treatments for patients with chronic low back pain is rather sobering. The effects on pain reduction and improvement of function are commonly small to moderate and short lasting when compared to placebo. At the same time, the various types of drugs are not without side-effects. This holds especially true for serious side-effects associated with (prolonged) use of strong opioids. Future studies on patients with chronic back pain should aim to identify subgroups of patients with good response to specific pharmacological treatment to facilitate personalized care.

Electromyographic activity of the erector spinae: The short-effect of one workday for welders with nonspecific chronic low back pain, an observational study

OBJECTIVE

This study aimed to evaluate the effect of one workday on pain and perceived exertion, muscular strength, and electromyographic activity of the erector spinae muscles in welders with and without low back pain. This is an observational cohort study.

PARTICIPANTS

Twenty-two welders, metallurgical shipbuilding, were equally divided into 2 groups: low back pain and no low back pain. Pain and perceived exertion. Muscular strength by maximal voluntary contractions and electromyographic activity of right and left erector spinae muscles during maximal voluntary contractions and in the 3 welding positions for 2 periods of the workday (in the morning and at the end of the workday).

RESULTS

At the end of workday, the pain increased significantly for the low back pain group (t(22) = 2.448; P= 0.023). The perceived exertion also increased significantly for both groups at the end of workday groups (F(1,22) = 8.570, P= 0.000) and periods (F(1,22) = 8.142, P= 0.000). There were no significant differences between groups and workday periods for muscular strength and electromyographic activity during maximal voluntary contractions of the erector spinae. There was no significance difference for electromyographic activity between groups and workday period and in the 3 welding positions.

CONCLUSION

Although the pain and perceived exertion increased at the end of the workday, these results did not interfere in muscular strength and electromyographic activity of right and left erector spinae muscles. Thus, we can conclude that welders with chronic low back pain had a good physical capacity (muscular strength) and that muscle performance was maintained.

Low Back Pain: What Have Clinical Guidelines Ever Done for Us?

The burden that low back pain (LBP) presents to sufferers and society is well established. This ubiquitous condition is served by a complex global clinical marketplace offering a wide range of assessment alternatives and accompanying interventions. Yet, while the costs of care are rising, the global burden does not appear to be diminishing. Considerable effort internationally has gone into developing CPGs for LBP. The authors highlight the similarities and differences between existing CPGs for LBP, as well as strengths, weaknesses, and opportunities for improvement in the implementation of guidelines generally. J Orthop Sports Phys Ther 2018;48(2):54-57. doi:10.2519/jospt.2018.0602.

Acute Low Back Pain: Differential Somatosensory Function and Gene Expression Compared With Healthy No-Pain Controls

OBJECTIVES

Low back pain (LBP) is the second most frequently diagnosed pain condition in the United States, and although a majority of individuals have resolution of pain during the acute period, an estimated 40% of individuals will experience persistent pain. Given the heterogenous nature of LBP, this study sought to describe and compare somatosensory and molecular (gene expression) profiles between individuals with acute LBP and healthy no-pain controls.

METHODS

Using a previously established protocol, we comprehensively assessed somatosensory parameters among 31 no-pain control participants and 31 participants with acute LBP. Samples of whole blood were drawn to examine mRNA expression of candidate genes involved in the transduction, maintenance, and modulation of pain.

RESULTS

The acute LBP group exhibited increased pain sensitivity to cold stimuli, mechanical stimuli, including mechanical temporal summation at both the painful back area and remote location suggesting a mechanism of enhanced central nervous system excitability. In addition, deep tissue-specific peripheral sensitization was suggested due to significant differences in pressure pain threshold of the painful back area, but not the remote body site. Several genes that were differentially expressed were significantly associated with somatosensory alterations identified in the acute LBP group.

DISCUSSION

Acute LBP participants showed selective pain sensitivity enhancement and differential gene expression profiles compared with pain-free controls. Further research to characterize pain-associated somatosensory changes in the context of altered mRNA expression levels may provide insight on the molecular underpinnings of maladaptive chronic pain.

Prevalence and reliability of treatment-based classification for subgrouping patients with low back pain

Objectives

To observe the distribution of patients who presented with low back pain (LBP) and to determine the between therapists' interrater reliability of assessments in a private outpatient setting using treatment-based classification (TBC) subgroups.

Methods

An observational and methodological study was conducted. Four hundred and twenty-nine patients (231 male; 198 female) presenting LBP symptoms and referred to conservative treatment were assessed by 13 physical therapists who conducted a 60-min examination process utilizing TBC subgroups. Interrater reliability analyses from six raters were assessed using Fleiss' kappa and previously recorded data (n = 30).

Results

In this study, 65.74% of patients were classified in only one subgroup, the most prevalent being stabilization (21.91%), followed by extension (15.38%), traction (11.89%), flexion (10.96%), manipulation (5.13%), and lateral shift (0.47%). Approximately 20.98% of patients were classified in two subgroups, where the most frequent overlaps were flexion + stabilization (7.46%), extension + stabilization (6.06%), flexion + traction (4.20%), extension + manipulation (1.86%), and 13.29% of patients were not classified in any TBC subgroup. Analysis of interrater reliability showed a kappa value of 0.62 and an overall agreement of 66% between raters.

Discussion

LBP is a heterogeneous clinical condition and several classification methods are proposed in the attempt to observe better outcomes for patients. Eighty-five percent of patients assessed were able to be classified when using the TBC assessment and reliability analysis showed a substantial agreement between raters.

Level of Evidence

2c.

Which patient-reported factors predict referral to spinal surgery? A cohort study among 4987 chronic low back pain patients

PURPOSE

It is unknown which chronic low back pain (CLBP) patients are typically referred to spinal surgery. The present study, therefore, aimed to explore which patient-reported factors are predictive of spinal surgery referral among CLBP patients.

METHODS

CLBP patients were consecutively recruited from a Dutch orthopedic hospital specialized in spine care (n = 4987). The outcome of this study was referral to spinal surgery (yes/no), and was assessed using hospital records. Possible predictive factors were assessed using a screening questionnaire. A prediction model was constructed using logistic regression, with backwards selection and p < 0.10 for keeping variables in the model. The model was internally validated and evaluated using discrimination and calibration measures.

RESULTS

Female gender, previous back surgery, high intensity leg pain, somatization, and positive treatment expectations increased the odds of being referred to spinal surgery, while being obese, having comorbidities, pain in the thoracic spine, increased walking distance, and consultation location decreased the odds. The model's fit was good (X ² = 10.5; p = 0.23), its discriminative ability was poor (AUC = 0.671), and its explained variance was low (5.5%). A post hoc analysis indicated that consultation location was significantly associated with spinal surgery referral, even after correcting for case-mix variables.

CONCLUSION

Some patient-reported factors could be identified that are predictive of spinal surgery referral. Although the identified factors are known as common predictive factors of surgery outcome, they could only partly predict spinal surgery referral.

Clinical classification in low back pain: best-evidence diagnostic rules based on systematic reviews

Background

Clinical examination findings are used in primary care to give an initial diagnosis to patients with low back pain and related leg symptoms. The purpose of this study was to develop best evidence Clinical Diagnostic Rules (CDR] for the identification of the most common patho-anatomical disorders in the lumbar spine; i.e. intervertebral discs, sacroiliac joints, facet joints, bone, muscles, nerve roots, muscles, peripheral nerve tissue, and central nervous system sensitization.

Methods

A sensitive electronic search strategy using MEDLINE, EMBASE and CINAHL databases was combined with hand searching and citation tracking to identify eligible studies. Criteria for inclusion were: persons with low back pain with or without related leg symptoms, history or physical examination findings suitable for use in primary care, comparison with acceptable reference standards, and statistical reporting permitting calculation of diagnostic value. Quality assessments were made independently by two reviewers using the Quality Assessment of Diagnostic Accuracy Studies tool. Clinical examination findings that were investigated by at least two studies were included and results that met our predefined threshold of positive likelihood ratio ≥ 2 or negative likelihood ratio ≤ 0.5 were considered for the CDR.

Results

Sixty-four studies satisfied our eligible criteria. We were able to construct promising CDRs for symptomatic intervertebral disc, sacroiliac joint, spondylolisthesis, disc herniation with nerve root involvement, and spinal stenosis. Single clinical test appear not to be as useful as clusters of tests that are more closely in line with clinical decision making.

Conclusions

This is the first comprehensive systematic review of diagnostic accuracy studies that evaluate clinical examination findings for their ability to identify the most common patho-anatomical disorders in the lumbar spine. In some diagnostic categories we have sufficient evidence to recommend a CDR. In others, we have only preliminary evidence that needs testing in future studies. Most findings were tested in secondary or tertiary care. Thus, the accuracy of the findings in a primary care setting has yet to be confirmed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1549-6) contains supplementary material, which is available to authorized users.

Subgrouping Patients With Nonspecific Low Back Pain: Hope or Hype?

Clinicians and clinical researchers share a common goal of achieving better outcomes for patients with low back pain (LBP). For that, randomized controlled trials and systematic reviews are the most reliable study designs to determine the effects of interventions. Subgroup analyses in these research designs have been used to examine treatment-effect modification across subgroups defined by patient characteristics. In this Viewpoint, the authors present supporting and opposing arguments for the subgrouping approach in nonspecific LBP, considering the progress made so far in the LBP field and the relevant literature in adjacent fields. J Orthop Sports Phys Ther 2017;47(2):44-48. doi:10.2519/jospt.2017.0602.

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.

Identifying back pain subgroups: developing and applying approaches using individual patient data collected within clinical trials

Background

There is good evidence that therapist-delivered interventions have modest beneficial effects for people with low back pain (LBP). Identification of subgroups of people with LBP who may benefit from these different treatment approaches is an important research priority.

Aim and objectives

To improve the clinical effectiveness and cost-effectiveness of LBP treatment by providing patients, their clinical advisors and health-service purchasers with better information about which participants are most likely to benefit from which treatment choices. Our objectives were to synthesise what is already known about the validity, reliability and predictive value of possible treatment moderators (patient factors that predict response to treatment) for therapist-delivered interventions; develop a repository of individual participant data from randomised controlled trials (RCTs) testing therapist-delivered interventions for LBP; determine which participant characteristics, if any, predict clinical response to different treatments for LBP; and determine which participant characteristics, if any, predict the most cost-effective treatments for LBP. Achieving these objectives required substantial methodological work, including the development and evaluation of some novel statistical approaches. This programme of work was not designed to analyse the main effect of interventions and no such interpretations should be made.

Methods

First, we reviewed the literature on treatment moderators and subgroups. We initially invited investigators of trials of therapist-delivered interventions for LBP with > 179 participants to share their data with us; some further smaller trials that were offered to us were also included. Using these trials we developed a repository of individual participant data of therapist-delivered interventions for LBP. Using this data set we sought to identify which participant characteristics, if any, predict response to different treatments (moderators) for clinical effectiveness and cost-effectiveness outcomes. We undertook an analysis of covariance to identify potential moderators to apply in our main analyses. Subsequently, we developed and applied three methods of subgroup identification: recursive partitioning (interaction trees and subgroup identification based on a differential effect search); adaptive risk group refinement; and an individual participant data indirect network meta-analysis (NWMA) to identify subgroups defined by multiple parameters.

Results

We included data from 19 RCTs with 9328 participants (mean age 49 years, 57% females). Our prespecified analyses using recursive partitioning and adaptive risk group refinement performed well and allowed us to identify some subgroups. The differences in the effect size in the different subgroups were typically small and unlikely to be clinically meaningful. Increasing baseline severity on the outcome of interest was the strongest driver of subgroup identification that we identified. Additionally, we explored the application of Bayesian indirect NWMA. This method produced varying probabilities that a particular treatment choice would be most likely to be effective for a specific patient profile.

Conclusions

These data lack clinical effectiveness or cost-effectiveness justification for the use of baseline characteristics in the development of subgroups for back pain. The methodological developments from this work have the potential to be applied in other clinical areas. The pooled repository database will serve as a valuable resource to the LBP research community.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme. This project benefited from facilities funded through Birmingham Science City Translational Medicine Clinical Research and Infrastructure Trials Platform, with support from Advantage West Midlands (AWM) and the Wolfson Foundation.

A systematic review reveals that the credibility of subgroup claims in low back pain trials was low

OBJECTIVES

To assess the credibility of subgroup claims in back pain randomized controlled trials.

STUDY DESIGN AND SETTING

A sample of reports of back pain trials from 2000 to 2015 that provided a subgroup claim were included (n=38). Two reviewers independently assessed risk of bias and credibility of subgroup claims as well as the strength of the author's claim. The credibility of subgroup claims was assessed using a 10-criteria tool, and strength of the subgroup claims was assessed based on seven criteria to categorize claims into a reasonably strong claim of a definitive subgroup effect or a more cautious claim of a possible effect.

RESULTS

A total of 91 claims of a subgroup effect were reported in the 38 included trials, of which 28 were considered strong claims of a definitive effect, and 63 were cautious claims of a possible effect. None of the subgroup claims met all 10 credibility criteria, and only 24% (22 claims) satisfied at least five criteria. The only criteria satisfied by more than 50% of the claims were if the subgroup variable was a characteristic measured at baseline, and whether the test of interaction was significant. All other criteria were satisfied by less than 30% of the claims. There was no association between the credibility of subgroup claims and the journal impact factor, risk of bias, sample size, or year of publication.

CONCLUSION

The credibility of subgroup claims in back pain trials is usually low, irrespective of the strength of the authors' claim.

Identifying Patients With Chronic Low Back Pain Who Respond Best to Mechanical Diagnosis and Therapy: Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

"Mechanical Diagnosis and Therapy" (MDT) (also known as the McKenzie method), like other interventions for low back pain (LBP), has been found to have small effects for people with LBP. It is possible that a group of patients respond best to MDT and have larger effects. Identification of patients who respond best to MDT compared with other interventions would be an important finding.

OBJECTIVE

The purpose of the study was to investigate whether baseline characteristics of patients with chronic LBP, already classified as derangement syndrome, can identify those who respond better to MDT compared with Back School.

METHODS

This study was a secondary analysis of data from a previous trial comparing MDT with Back School in 148 patients with chronic LBP. Only patients classified at baseline assessment as being in the directional preference group (n=140) were included. The effect modifiers tested were: clear centralization versus directional preference only, baseline pain location, baseline pain intensity, and age. The primary outcome measures for this study were pain intensity and disability at the end of treatment (1 month). Treatment effect modification was evaluated by assessing the group versus predictor interaction terms from linear regression models. Interactions ≥1.0 for pain and ≥3 for disability were considered clinically important.

RESULTS

Being older met our criteria for being a potentially important effect modifier; however, the effect occurred in the opposite direction to our hypothesis. Older people had 1.27 points more benefit in pain reduction from MDT (compared with Back School) than younger participants after 1 month of treatment.

LIMITATIONS

The sample (n=140) was powered to detect the main effects of treatment but not to detect the interactions of the potential treatment effect modifiers.

CONCLUSIONS

The results of the study suggest older age may be an important factor that can be considered as a treatment effect modifier for patients with chronic LBP receiving MDT. As the main trial was not powered for the investigation of subgroups, the results of this secondary analysis have to be interpreted cautiously, and replication is needed.

Psychological and behavioral differences between low back pain populations: a comparative analysis of chiropractic, primary and secondary care patients

Background

Psychological, behavioral and social factors have long been considered important in the development of persistent pain. Little is known about how chiropractic low back pain (LBP) patients compare to other LBP patients in terms of psychological/behavioral characteristics.

Methods

In this cross-sectional study, the aim was to investigate patients with LBP as regards to psychosocial/behavioral characteristics by describing a chiropractic primary care population and comparing this sample to three other populations using the MPI-S instrument. Thus, four different samples were compared. A: Four hundred eighty subjects from chiropractic primary care clinics. B: One hundred twenty-eight subjects from a gainfully employed population (sick listed with high risk of developing chronicity). C: Two hundred seventy-three subjects from a secondary care rehabilitation clinic. D: Two hundred thirty-five subjects from secondary care clinics. The Swedish version of the Multidimensional Pain Inventory (MPI-S) was used to collect data. Subjects were classified using a cluster analytic strategy into three pre-defined subgroups (named adaptive copers, dysfunctional and interpersonally distressed).

Results

The data show statistically significant overall differences across samples for the subgroups based on psychological and behavioral characteristics. The cluster classifications placed (in terms of the proportions of the adaptive copers and dysfunctional subgroups) sample A between B and the two secondary care samples C and D.

Conclusions

The chiropractic primary care sample was more affected by pain and worse off with regards to psychological and behavioral characteristics compared to the other primary care sample. Based on our findings from the MPI-S instrument the 4 samples may be considered statistically and clinically different.

Trial registration

Sample A comes from an ongoing trial registered at clinical trials.gov; NCT01539863, February 22, 2012.

Massage for low-back pain

BACKGROUND

Low-back pain (LBP) is one of the most common and costly musculoskeletal problems in modern society. It is experienced by 70% to 80% of adults at some time in their lives. Massage therapy has the potential to minimize pain and speed return to normal function.

OBJECTIVES

To assess the effects of massage therapy for people with non-specific LBP.

SEARCH METHODS

We searched PubMed to August 2014, and the following databases to July 2014: MEDLINE, EMBASE, CENTRAL, CINAHL, LILACS, Index to Chiropractic Literature, and Proquest Dissertation Abstracts. We also checked reference lists. There were no language restrictions used.

SELECTION CRITERIA

We included only randomized controlled trials of adults with non-specific LBP classified as acute, sub-acute or chronic. Massage was defined as soft-tissue manipulation using the hands or a mechanical device. We grouped the comparison groups into two types: inactive controls (sham therapy, waiting list, or no treatment), and active controls (manipulation, mobilization, TENS, acupuncture, traction, relaxation, physical therapy, exercises or self-care education).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures and followed CBN guidelines. Two independent authors performed article selection, data extraction and critical appraisal.

MAIN RESULTS

In total we included 25 trials (3096 participants) in this review update. The majority was funded by not-for-profit organizations. One trial included participants with acute LBP, and the remaining trials included people with sub-acute or chronic LBP (CLBP). In three trials massage was done with a mechanical device, and the remaining trials used only the hands. The most common type of bias in these studies was performance and measurement bias because it is difficult to blind participants, massage therapists and the measuring outcomes. We judged the quality of the evidence to be "low" to "very low", and the main reasons for downgrading the evidence were risk of bias and imprecision. There was no suggestion of publication bias. For acute LBP, massage was found to be better than inactive controls for pain ((SMD -1.24, 95% CI -1.85 to -0.64; participants = 51; studies = 1)) in the short-term, but not for function ((SMD -0.50, 95% CI -1.06 to 0.06; participants = 51; studies = 1)). For sub-acute and chronic LBP, massage was better than inactive controls for pain ((SMD -0.75, 95% CI -0.90 to -0.60; participants = 761; studies = 7)) and function (SMD -0.72, 95% CI -1.05 to -0.39; 725 participants; 6 studies; ) in the short-term, but not in the long-term; however, when compared to active controls, massage was better for pain, both in the short ((SMD -0.37, 95% CI -0.62 to -0.13; participants = 964; studies = 12)) and long-term follow-up ((SMD -0.40, 95% CI -0.80 to -0.01; participants = 757; studies = 5)), but no differences were found for function (both in the short and long-term). There were no reports of serious adverse events in any of these trials. Increased pain intensity was the most common adverse event reported in 1.5% to 25% of the participants.

AUTHORS' CONCLUSIONS

We have very little confidence that massage is an effective treatment for LBP. Acute, sub-acute and chronic LBP had improvements in pain outcomes with massage only in the short-term follow-up. Functional improvement was observed in participants with sub-acute and chronic LBP when compared with inactive controls, but only for the short-term follow-up. There were only minor adverse effects with massage.

Interpreting Effectiveness Evidence in Pain: Short Tour of Contemporary Issues

There is no shortage of treatment approaches offered to people with pain. The maze of options presents patients and clinicians with difficult choices. Key to making those choices is evidence of treatment effectiveness provided by clinical trials and systematic reviews. Recent growth in the number of clinical trials and systematic reviews, of both high and low quality, makes it vital that users of this evidence-clinicians, researchers, patients, and policy makers-have the skills and knowledge to critically interpret these studies. In this review, we discuss some contemporary issues regarding evidence of effectiveness derived from clinical trials and systematic reviews-issues that we think are critical to understanding the field. We focus on evidence of treatment effectiveness in pain, although many of these issues are relevant to and transferable across the spectrum of evidence-based practice.

Back pain: Prevention and management in the workplace

Despite all the efforts in studying work-related risk factors for low back pain (LBP), interventions targeting these risk factors to prevent LBP have no proven cost-effectiveness. Even with adequate implementation strategies for these interventions on group level, these did not result in the reduction of incident LBP. Physical exercise, however, does have a primary preventive effect on LBP. For secondary prevention, it seems that there are more opportunities to cost-effectively intervene in reducing the risk of long-term sickness absence due to LBP. Starting at the earliest moment possible with proper assessment of risk factors for long-term sickness absence related to the individual, the underlying mechanisms of the LBP, and also factors related to the workplace by a well-trained clinician, may increase the potential of effective return to work (RTW) management. More research on how to overcome barriers in the uptake of these effective interventions in relation to policy-specific environments, and with regard to proper financing of RTW management is necessary.

Low back pain-related meta-analysis: Caution is needed when interpreting published research results

The systematic reviews (SRs) including a meta-analysis are considered as the top level of evidence. Although the existence of more than a hundred of low back pain (LBP)-related SRs seems very appealing and might therefore suggest significant evidence on the topic, a deep analysis indicates that several of these SRs included only very few studies. Other SRs raise concerns because they included some randomized controlled trials which had a low methodological quality, or some studies which differed significantly regarding the studied populations and/or the experimental procedure. The sometimes controversial results of different SRs conducted on the same topic also highlight the significant influence of the inclusion/exclusion criteria used in the SRs to select the articles. To conclude, although meta-analysis is at the top of the evidence pyramid and have several strengths, the conclusions drawn from SRs should always be interpreted with caution because they can also have weaknesses. This is true, whether it be for LBP-related SRs including a meta-analysis, or any other. Therefore a critical analysis of any SR is always needed before integrating the results of the SR in its own clinical practice. Furthermore, clinical reasoning remains crucial, especially to consider the potential differences between one’s patient and the patients included in the meta-analysis.