Predicting response to a cognitive-behavioral approach to treating low back pain: Secondary analysis of the BeST data set

Moderators and Nonspecific Predictors of Treatment Benefits in a Randomized Trial of Mindfulness-Based Stress Reduction vs Cognitive-Behavioral Therapy vs Usual Care for Chronic Low Back Pain

Both mindfulness-based stress reduction (MBSR) and cognitive-behavioral therapy (CBT) are effective for chronic low back pain (CLBP), but little is known regarding who might benefit more from one than the other. Using data from a randomized trial comparing MBSR, CBT, and usual care (UC) for adults aged 20 to 70 years with CLBP (N = 297), we examined baseline characteristics that moderated treatment effects or were associated with improvement regardless of treatment. Outcomes included 8-week function (modified Roland Disability Questionnaire), pain bothersomeness (0-10 numerical rating scale), and depression (Patient Health Questionnaire-8). There were differences in the effects of CBT versus MBSR on pain based on participant gender (P = .03) and baseline depressive symptoms (P = .01), but the only statistically significant moderator after Bonferroni correction was the nonjudging dimension of mindfulness. Scores on this measure moderated the effects of CBT versus MBSR on both function (P = .001) and pain (P = .04). Pain control beliefs (P <.001) and lower anxiety (P < .001) predicted improvement regardless of treatment. Replication of these findings is needed to guide treatment decision-making for CLBP. TRIAL REGISTRATION: The trial and analysis plan were preregistered in ClinicalTrials.gov (Identifier: NCT01467843). PERSPECTIVE: Although few potential moderators and nonspecific predictors of benefits from CBT or MBSR for CLBP were statistically significant after adjustment for multiple comparisons, these findings suggest potentially fruitful directions for confirmatory research while providing reassurance that patients could reasonably expect to benefit from either treatment.

How do psychologically based interventions for chronic musculoskeletal pain work? A systematic review and meta-analysis of specific moderators and mediators of treatment

Psychologically based interventions aim to improve pain-related functioning by targeting pain-related fears, cognitions and behaviors. Mediation and moderation analyses permit further examination of the effect of treatment on an outcome. This systematic review and meta-analysis aims to synthetize the evidence of specific mediators and moderators (i.e., treatment targets) of psychologically based treatment effects on pain and disability. A total of 28 mediation and 11 moderation analyses were included. Thirteen mediation studies were included in a meta-analysis, and the rest was narratively synthetized. Reductions in pain-related fear (indirect effect [IE]: -0.07; 95% confidence interval [CI]: -0.11, -0.04) and catastrophizing (IE: -0.07; 95%CI: -0.14, -0.00), as well as increases in self-efficacy (IE: -0.07; 95%CI: -0.11, -0.04), mediated effects of cognitive behavioral therapy on disability but not on pain intensity, when compared to control treatments. Enhancing pain acceptance (IE: -0.17; 95%CI: -0.31, -0.03) and psychological flexibility (IE: -0.30; 95%CI: -0.41, -0.18) mediated acceptance and commitment therapy effects on disability. The narrative synthesis showed conflicting evidence, which did not support a robust moderated effect for any of the examined constructs. Overall, the methodological quality regarding mediation was low, and some key pitfalls are highlighted alongside recommendations to provide a platform for future research.

Do recommended interventions widen or narrow inequalities in musculoskeletal health? An equity-focussed systematic review of differential effectiveness

Background

It is unclear whether seven interventions recommended by Public Health England for preventing and managing common musculoskeletal conditions reduce or widen health inequalities in adults with musculoskeletal conditions.

Methods

We used citation searches of Web of Science (date of ‘parent publication’ for each intervention to April 2021) to identify original research articles reporting subgroup or moderator analyses of intervention effects by social stratifiers defined using the PROGRESS-Plus frameworks. Randomized controlled trials, controlled before-after studies, interrupted time series, systematic reviews presenting subgroup/stratified analyses or meta-regressions, individual participant data meta-analyses and modelling studies were eligible. Two reviewers independently assessed the credibility of effect moderation claims using Instrument to assess the Credibility of Effect Moderation Analyses. A narrative approach to synthesis was used (PROSPERO registration number: CRD42019140018).

Results

Of 1480 potentially relevant studies, seven eligible analyses of single trials and five meta-analyses were included. Among these, we found eight claims of potential differential effectiveness according to social characteristics, but none that were judged to have high credibility.

Conclusions

In the absence of highly credible evidence of differential effectiveness in different social groups, and given ongoing national implementation, equity concerns may be best served by investing in monitoring and action aimed at ensuring fair access to these interventions.

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).

Optimal search strategies for identifying moderators and predictors of treatment effects in PubMed

BACKGROUND

Treatment effects differ across patients. To guide selection of treatments for patients, it is essential to acknowledge these differences and identify moderators or predictors. Our aim was to generate optimal search strategies (commonly known as filters) for PubMed to retrieve papers identifying moderators and predictors of treatment effects.

METHODS

Six journals were hand-searched for articles on moderators or predictors. Selected articles were randomly allocated to a development and validation set. Search terms were extracted from the development set and tested for their performance. Search filters were created from combinations of these terms and tested in the validation set.

RESULTS

Of 4407 articles, 198 were considered to be relevant. The most sensitive filter in the development set '("Epidemiologic Methods" [MeSH] OR assign* OR control*[tiab] OR trial*[tiab]) AND therapy*[sh]' yielded in the validation set a sensitivity of 89% [88%-90%] and a specificity of 80% [79%-82%].

CONCLUSIONS

The search filters created in this study can help to efficiently retrieve evidence on moderators and predictors of treatment effect. Testing of the filters in multiple domains should reveal robustness across disciplines. These filters can facilitate the retrieval of evidence on moderators and predictors of treatment effects, helping the implementation of stratified or personalised health care.

Facet joint injections for people with persistent non-specific low back pain (Facet Injection Study): a feasibility study for a randomised controlled trial

BACKGROUND

The National Institute for Health and Care Excellence (NICE) 2009 guidelines for persistent low back pain (LBP) do not recommend the injection of therapeutic substances into the back as a treatment for LBP because of the absence of evidence for their effectiveness. This feasibility study aimed to provide a stable platform that could be used to evaluate a randomised controlled trial (RCT) on the clinical effectiveness and cost-effectiveness of intra-articular facet joint injections (FJIs) when added to normal care.

OBJECTIVES

To explore the feasibility of running a RCT to test the hypothesis that, for people with suspected facet joint back pain, adding the option of intra-articular FJIs (local anaesthetic and corticosteroids) to best usual non-invasive care is clinically effective and cost-effective.

DESIGN

The trial was a mixed design. The RCT pilot protocol development involved literature reviews and a consensus conference followed by a randomised pilot study with an embedded mixed-methods process evaluation.

SETTING

Five NHS acute trusts in England.

PARTICIPANTS

Participants were patients aged ≥ 18 years with moderately troublesome LBP present (> 6 months), who had failed previous conservative treatment and who had suspected facet joint pain. The study aimed to recruit 150 participants (approximately 30 per site). Participants were randomised sequentially by a remote service to FJIs combined with 'best usual care' (BUC) or BUC alone.

INTERVENTIONS

All participants were to receive six sessions of a bespoke BUC rehabilitation package. Those randomised into the intervention arm were, in addition, given FJIs with local anaesthetic and steroids (at up to six injection sites). Randomisation occurred at the end of the first BUC session.

MAIN OUTCOME MEASURES

Process and clinical outcomes. Clinical outcomes included a measurement of level of pain on a scale from 0 to 10, which was collected daily and then weekly via text messaging (or through a written diary). Questionnaire follow-up was at 3 months.

RESULTS

Fifty-two stakeholders attended the consensus meeting. Agreement informed several statistical questions and three design considerations: diagnosis, the process of FJI and the BUC package and informing the design for the randomised pilot study. Recruitment started on 26 June 2015 and was terminated by the funder (as a result of poor recruitment) on 11 December 2015. In total, 26 participants were randomised. Process data illuminate some of the reasons for recruitment problems but also show that trial processes after enrolment ran smoothly. No between-group analysis was carried out. All pain-related outcomes show the expected improvement between baseline and follow-up. The mean total cost of the overall treatment package (injection £419.22 and BUC £264.00) was estimated at £683.22 per participant. This is similar to a NHS tariff cost for a course of FJIs of £686.84.

LIMITATIONS

Poor recruitment was a limiting factor.

CONCLUSIONS

This feasibility study achieved consensus on the main challenges in a trial of FJIs for people with persistent non-specific low back pain.

FUTURE WORK

Further work is needed to test recruitment from alternative clinical situations.

TRIAL REGISTRATION

EudraCT 2014-000682-50 and Current Controlled Trials ISRCTN93184143.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 30. See the NIHR Journals Library website for further project information.

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 qualitative study of older people's experience of living with neurogenic claudication to inform the development of a physiotherapy intervention

PURPOSE

The aim of this study was to explore older people's experiences of living with neurogenic claudication (NC), their preferences for physiotherapy treatment provision and associated outcomes in order to inform an intervention to be tested in a clinical trial.

METHOD

Patients with a diagnosis of NC and/or lumbar spinal stenosis were recruited through a UK NHS tertiary care center. Semi-structured interviews and self-report questionnaires were used to obtain data. A thematic analysis was conducted.

RESULTS

15 participants were recruited; half were classed as frail older adults. Pain and the threat of pain was a prominent feature of participants' experience of NC. This led to a loss of engagement in meaningful activities and sense of self. Discourses of ageing influenced experiences as well as treatment preferences, particularly the acceptability of walking aids. A combination of one-to-one and group setting for treatment was preferred. Outcome preferences related to re-engagement in meaningful activities and pain reduction. Limitations relate to generalisability of the findings for NC patients not under physiotherapy treatment.

CONCLUSION

We have obtained important findings about older people's experiences of living with NC and preferences for physiotherapy treatment and outcomes. These will be incorporated into an evidence-based intervention and evaluated in a randomized controlled trial. Implications for rehabilitation Older people living with NC want to get back to meaningful activities and learn how to live with the threat of pain. Allied health professionals (AHPs) should be sensitive to the complex and ambiguous ways in which older people live with ageing and age-related decline. AHPs are in a position to support patients' successful transition to the use of walking aids thereby reducing stigmatizing effects and increasing activity. AHPs should consider a mixture of one-to-one and group classes to enable rehabilitation for older NC patients.

The effect of journal impact factor, reporting conflicts, and reporting funding sources, on standardized effect sizes in back pain trials: a systematic review and meta-regression

BACKGROUND

Low back pain is a common and costly health complaint for which there are several moderately effective treatments. In some fields there is evidence that funder and financial conflicts are associated with trial outcomes. It is not clear whether effect sizes in back pain trials relate to journal impact factor, reporting conflicts of interest, or reporting funding.

METHODS

We performed a systematic review of English-language papers reporting randomised controlled trials of treatments for non-specific low back pain, published between 2006-2012. We modelled the relationship using 5-year journal impact factor, and categories of reported of conflicts of interest, and categories of reported funding (reported none and reported some, compared to not reporting these) using meta-regression, adjusting for sample size, and publication year. We also considered whether impact factor could be predicted by the direction of outcome, or trial sample size.

RESULTS

We could abstract data to calculate effect size in 99 of 146 trials that met our inclusion criteria. Effect size is not associated with impact factor, reporting of funding source, or reporting of conflicts of interest. However, explicitly reporting 'no trial funding' is strongly associated with larger absolute values of effect size (adjusted β=1.02 (95 % CI 0.44 to 1.59), P=0.001). Impact factor increases by 0.008 (0.004 to 0.012) per unit increase in trial sample size (P<0.001), but does not differ by reported direction of the LBP trial outcome (P=0.270).

CONCLUSIONS

The absence of associations between effect size and impact factor, reporting sources of funding, and conflicts of interest reflects positively on research and publisher conduct in the field. Strong evidence of a large association between absolute magnitude of effect size and explicit reporting of 'no funding' suggests authors of unfunded trials are likely to report larger effect sizes, notwithstanding direction. This could relate in part to quality, resources, and/or how pragmatic a trial is.

Does a preoperative cognitive-behavioral intervention affect disability, pain behavior, pain, and return to work the first year after lumbar spinal fusion surgery?

STUDY DESIGN

A randomized clinical trial including 90 patients.

OBJECTIVE

To examine the effect of a preoperative cognitive-behavioral intervention (CBT) for patients undergoing lumbar spinal fusion (LSF) surgery.

SUMMARY OF BACKGROUND DATA

Few published studies have looked at the potential of rehabilitation to improve outcomes after LSF. Rehabilitation programs using CBT are recommended. Furthermore, initiating interventions preoperatively seems beneficial, but only limited data exist in the field of spine surgery.

METHODS

Patients with degenerative disc disease or spondylolisthesis undergoing LSF were randomized to usual care (control group) or preoperative CBT and usual care (CBT group). Primary outcome was change in Oswestry Disability Index from baseline to 1-year follow-up. Secondary outcomes were catastrophizing, fear avoidance belief, work status, and back and leg pain.

RESULTS

At 1-year follow-up, there was no statistically significant difference between the CBT group and the control group in Oswestry Disability Index score (P = 0.082). However, the CBT group had achieved a significant reduction of -15 points (-26; -4) already at 3 months (between group difference P = 0.003), and this reduction was maintained throughout the year. There were no differences between groups at 1-year follow-up with regard to any of the secondary outcomes.

CONCLUSION

Participating in a preoperative CBT intervention in addition to usual care did not produce better outcomes at 1-year follow-up for patients undergoing LSF. Although the reduction in disability was achieved much faster in the CBT group, resulting in a significant difference between groups already 3 months after surgery, it did not translate into a faster return to work. Our findings support the need for further research into the use of targeted rehabilitation interventions among patients with elevated levels of catastrophizing and fear avoidance beliefs.

LEVEL OF EVIDENCE

2.

Identifying potential moderators for response to treatment in low back pain: A systematic review

BACKGROUND

Identifying which patients with non-specific low back pain are likely to gain the greatest benefit from different treatments is an important research priority. Few studies are large enough to produce data on sub-group effects from different treatments. Data from existing large studies may help identify potential moderators to use in future individual patient data meta-analyses.

OBJECTIVE

To systematically review papers of therapist delivered interventions for low back pain to identify potential moderators to inform an individual patient data meta-analysis.

DATA SOURCES

We searched MEDLINE, EMBASE, Web of Science and Citation Index and Cochrane Register of Controlled Trials (CENTRALhttp://www.cochrane.org/editorial-and-publishing-policy-resource/cochrane-central-register-controlled-trials-central) for relevant papers.

DATA EXTRACTION AND DATA SYNTHESIS

We screened for randomised controlled trials with ≥500 or more participants, and cohort studies of ≥1000 or more participants. We examined all publications related to these studies for any reported moderator analyses. Two reviewers independently did risk of bias assessment of main results and quality assessment of any moderator analyses.

RESULTS

We included four randomised trials (n=7208). Potential moderators with strong evidence (p<0.05) in one or more studies were age, employment status and type, back pain status, narcotic medication use, treatment expectations and education. Potential moderators with weaker evidence (0.05<p≤0.20) included gender, psychological distress, pain/disability and quality of life.

CONCLUSION

There are insufficient robust data on moderators to be useful in clinical practice. This review has identified some important potential moderators of treatment effect worthy of testing in future confirmatory analyses.

Fear-avoidance beliefs-a moderator of treatment efficacy in patients with low back pain: a systematic review

BACKGROUND CONTEXT

Psychological factors are believed to influence the development of chronic low back pain. To date, it is not known how fear-avoidance beliefs (FABs) influence the treatment efficacy in low back pain.

PURPOSE

To summarize the evidence examining the influence of FABs measured with the Fear-Avoidance Belief Questionnaire or the Tampa Scale of Kinesiophobia on treatment outcomes in patients with low back pain.

STUDY DESIGN/SETTING

This is a systematic review.

PATIENT SAMPLE

Patients with low back pain.

OUTCOME MEASURES

Work-related outcomes and perceived measures including return to work, pain, and disability.

METHODS

In January 2013, the following databases were searched: BIOSIS, CINAHL, Cochrane Library, Embase, OTSeeker, PeDRO, PsycInfo, PubMed/Medline, Scopus, and Web of Science. A hand search of the six most often retrieved journals and a bibliography search completed the search.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

research studies that included patients with low back pain who participated in randomized controlled trials (RCTs) investigating nonoperative treatment efficacy. Out of 646 records, 78 articles were assessed in full text and 17 RCTs were included. Study quality was high in five studies and moderate in 12 studies.

RESULTS

In patients with low back pain of up to 6 months duration, high FABs were associated with more pain and/or disability (4 RCTs) and less return to work (3 RCTs) (GRADE high-quality evidence, 831 patients vs. 322 in nonpredictive studies). A decrease in FAB values during treatment was associated with less pain and disability at follow-up (GRADE moderate evidence, 2 RCTs with moderate quality, 242 patients). Interventions that addressed FABs were more effective than control groups based on biomedical concepts (GRADE moderate evidence, 1,051 vs. 227 patients in studies without moderating effects). In chronic patients with LBP, the findings were less consistent. Two studies found baseline FABs to be associated with more pain and disability and less return to work (339 patients), whereas 3 others (832 patients) found none (GRADE low evidence). Heterogeneity of the studies impeded a pooling of the results.

CONCLUSIONS

Evidence suggests that FABs are associated with poor treatment outcome in patients with LBP of less than 6 months, and thus early treatment, including interventions to reduce FABs, may avoid delayed recovery and chronicity. Patients with high FABs are more likely to improve when FABs are addressed in treatments than when these beliefs are ignored, and treatment strategies should be modified if FABs are present.

Matching patients to an intervention for back pain: classifying patients using a latent class approach

RATIONALE, AIMS AND OBJECTIVES

Classification of patients with back pain in order to inform treatments is a long-standing aim in medicine. We used latent class analysis (LCA) to classify patients with low back pain and investigate whether different classes responded differently to a cognitive behavioural intervention. The objective was to provide additional guidance on the use of cognitive behavioural therapy to both patients and clinicians.

METHOD

We used data from 407 participants from the full study population of 701 with complete data at baseline for the variables the intervention was designed to affect and complete data at 12 months for important outcomes. Patients were classified using LCA, and a link between class membership and outcome was investigated. For comparison, the latent class partition was compared with a commonly used classification system called Subgroups for Targeted Treatment (STarT).

RESULTS

Of the relatively parsimonious models tested for association between class membership and outcome, an association was only found with one model which had three classes. For the trial participants who received the intervention, there was an association between class membership and outcome, but not for those who did not receive the intervention. However, we were unable to detect an effect on outcome from interaction between class membership and the intervention. The results from the comparative classification system were similar.

CONCLUSION

We were able to classify the trial participants based on psychosocial baseline scores relevant to the intervention. An association between class membership and outcome was identified for those people receiving the intervention, but not those in the control group. However, we were not able to identify outcome associations for individual classes and so predict outcome in order to aid clinical decision making. For this cohort of patients, the STarT system was as successful, but not superior.

Evaluating the quality of subgroup analyses in randomized controlled trials of therapist-delivered interventions for nonspecific low back pain: a systematic review

STUDY DESIGN

Systematic review.

OBJECTIVE

To evaluate the quality, conduct, and reporting of subgroup analyses performed in randomized controlled trials of therapist-delivered interventions for nonspecific low back pain (NSLBP).

SUMMARY OF BACKGROUND DATA

Randomized controlled trials of therapist-delivered interventions for NSLBP to date have, at best, shown small to moderate positive effects. Identifying subgroups is an important research priority. This review evaluates the quality, conduct, and reporting of subgroup analyses performed in the NSLBP literature.

METHODS

Multiple electronic databases were searched for randomized controlled trials of therapist-delivered interventions for NSLBP. Of the identified articles, only articles reporting subgroup analyses (confirmatory or exploratory) were included in the final review. Methodological criteria were used to evaluate the quality of subgroup analyses. The quality of conduct and reporting was also evaluated.

RESULTS

Thirty-nine articles were included in the final review. Of these, only 3 (8%) tested hypotheses about moderators (confirmatory findings), 18 (46%) generated hypotheses about moderators to inform future research (exploratory findings), and 18 (46%) provided insufficient findings. The appropriate statistical test for interaction was performed in 27 of the articles, of which 10 reported results from interaction tests, 4 incorrectly reported results within individual subgroups, and the remaining articles reported either P values or nothing at all.

CONCLUSION

Subgroup analyses performed in NSLBP trials have been severely underpowered, are only able to provide exploratory or insufficient findings, and have rather poor quality of reporting. Using current approaches, few definitive trials of subgrouping in back pain are very likely to be performed. There is a need to develop new approaches to subgroup identification in back pain research.

Exercise therapy for chronic low back pain: protocol for an individual participant data meta-analysis

BACKGROUND

Low back pain (LBP) is one of the leading causes of disability and has a major socioeconomic impact. Despite a large amount of research in the field, there remains uncertainty about the best treatment approach for chronic LBP, and identification of relevant patient subgroups is an important goal. Exercise therapy is a commonly used strategy to treat chronic low back pain and is one of several interventions that evidence suggests is moderately effective.In parallel with an update of the 2005 Cochrane review, we will undertake an individual participant data (IPD) meta-analysis, which will allow us to standardize analyses across studies and directly derive results, and to examine differential treatment effects across individuals to estimate how patients' characteristics modify treatment benefit.

METHODS/DESIGN

We will use standard systematic review methods advocated by the Cochrane Collaboration to identify relevant trials. We will include trials evaluating exercise therapy compared to any or no other interventions in adult non-specific chronic LBP. Our primary outcomes of interest include pain, functional status, and return-to-work/absenteeism. We will assess potential risk of bias for each study meeting selection criteria, using criteria and methods recommended by the Cochrane BRG.The original individual participant data will be requested from the authors of selected trials having moderate to low risk of bias. We will test original data and compile a master dataset with information about each trial mapped on a pre-specified framework, including reported characteristics of the study sample, exercise therapy characteristics, individual patient characteristics at baseline and all follow-up periods, subgroup and treatment effect modifiers investigated. Our analyses will include descriptive, study-level meta-analysis and meta-regression analyses of the overall treatment effect, and individual-level IPD meta-analyses of treatment effect modification. IPD meta-analyses will be conducted using a one-step approach where the IPD from all studies are modeled simultaneously while accounting for the clustering of participants with studies.

DISCUSSION

We will analyze IPD across a large number of LBP trials. The resulting larger sample size and consistent presentation of data will allow additional analyses to explore patient-level heterogeneity in treatment outcomes and prognosis of chronic LBP.

Psychological therapies for the management of chronic pain (excluding headache) in adults

BACKGROUND

Psychological treatments are designed to treat pain, distress and disability, and are in common practice. This review updates and extends the 2009 version of this systematic review.

OBJECTIVES

To evaluate the effectiveness of psychological therapies for chronic pain (excluding headache) in adults, compared with treatment as usual, waiting list control, or placebo control, for pain, disability, mood and catastrophic thinking.

SEARCH METHODS

We identified randomised controlled trials (RCTs) of psychological therapy by searching CENTRAL, MEDLINE, EMBASE and Psychlit from the beginning of each abstracting service until September 2011. We identified additional studies from the reference lists of retrieved papers and from discussion with investigators.

SELECTION CRITERIA

Full publications of RCTs of psychological treatments compared with an active treatment, waiting list or treatment as usual. We excluded studies if the pain was primarily headache, or was associated with a malignant disease. We also excluded studies if the number of patients in any treatment arm was less than 20.

DATA COLLECTION AND ANALYSIS

Forty-two studies met our criteria and 35 (4788 participants) provided data. Two authors rated all studies. We coded risk of bias as well as both the quality of the treatments and the methods using a scale designed for the purpose. We compared two main classes of treatment (cognitive behavioural therapy(CBT) and behaviour therapy) with two control conditions (treatment as usual; active control) at two assessment points (immediately following treatment and six months or more following treatment), giving eight comparisons. For each comparison, we assessed treatment effectiveness on four outcomes: pain, disability, mood and catastrophic thinking, giving a total of 32 possible analyses, of which there were data for 25.

MAIN RESULTS

Overall there is an absence of evidence for behaviour therapy, except a small improvement in mood immediately following treatment when compared with an active control. CBT has small positive effects on disability and catastrophising, but not on pain or mood, when compared with active controls. CBT has small to moderate effects on pain, disability, mood and catastrophising immediately post-treatment when compared with treatment as usual/waiting list, but all except a small effect on mood had disappeared at follow-up. At present there are insufficient data on the quality or content of treatment to investigate their influence on outcome. The quality of the trial design has improved over time but the quality of treatments has not.

AUTHORS' CONCLUSIONS

Benefits of CBT emerged almost entirely from comparisons with treatment as usual/waiting list, not with active controls. CBT but not behaviour therapy has weak effects in improving pain, but only immediately post-treatment and when compared with treatment as usual/waiting list. CBT but not behaviour therapy has small effects on disability associated with chronic pain, with some maintenance at six months. CBT is effective in altering mood and catastrophising outcomes, when compared with treatment as usual/waiting list, with some evidence that this is maintained at six months. Behaviour therapy has no effects on mood, but showed an effect on catastrophising immediately post-treatment. CBT is a useful approach to the management of chronic pain. There is no need for more general RCTs reporting group means: rather, different types of studies and analyses are needed to identify which components of CBT work for which type of patient on which outcome/s, and to try to understand why.

Results of a 2-week inpatient stay at the department for internal and integrative medicine: an observational study

Introduction. The Department for Internal and Integrative Medicine in Essen utilizes mind/body medical elements in order to empower patients with chronic diseases to better cope with their symptoms and to adopt a healthy lifestyle. This study explored the influence and predictors of a 2-week integrative treatment program on patients' quality of life. Methods. This observational study was conducted with inpatients as part of the quality assurance program. Patients' quality of life, psychological symptoms, and health locus of control were measured on admission and discharge and again 3, 6, and 12 months after discharge. Regression analyses were conducted to determine the factors predicting improved quality of life. Results. Data from 2486 inpatients treated in 2001–2004 were included (80% female, mean age 53.9 ± 14.3 years). Response rates decreased to 50% at 12 months. Small-to-moderate effects were found on patients' quality of life, anxiety, and depression. Patients' internal locus of control significantly increased. Improved quality of life was mainly predicted by lower baseline scores. Conclusion. Results of this study suggest that a 2-week inpatient treatment might sustainably reduce patients' symptoms and increase their quality of life; however, conclusions are only preliminary. More research is needed to enable the effectiveness to be judged conclusively.

Group cognitive behavioural interventions for low back pain in primary care: extended follow-up of the Back Skills Training Trial (ISRCTN54717854)

Group cognitive behavioural intervention (CBI) is effective in reducing low back pain and disability over a 12-month period, in comparison to best practice advice in primary care. The aim was to study the effects of this CBI beyond 12 months. We undertook an extended follow-up of our original randomised, controlled trial of a group CBI and best practice advice in primary care, in comparison to best practice advice alone. Participants were mailed a questionnaire including measures of disability, pain, health services resource use, and health-related quality of life. The time of extended follow-up ranged between 20 and 50 months (mean 34 months). Fifty-six percent (395 of 701) of the original cohort provided extended follow-up. Those who responded were older and had less disability and pain at baseline than did the original trial cohort. After 12 months, the improvements in pain and disability observed with CBI were sustained. For disability measures, the treatment difference in favour of CBI persisted (mean difference 1.3 Roland and Morris Disability Questionnaire points, 95% confidence interval 0.27 to 2.26; 5.5 Modified von Korff Scale disability points, 95% confidence interval 0.27 to 10.64). There was no between-group difference in Modified von Korff Scale pain outcomes. The results suggest that the effects of a group CBI are maintained up to an average of 34 months. Although pain improves in response to best practice advice, longer-term recovery of disability remains substantially less.