Clinical validation of grouping conservative treatments in neck pain for use in a network meta-analysis: a Delphi consensus study.

BACKGROUND: A network meta-analysis aims to help clinicians make clinical decisions on the most effective treatment for a certain condition. Neck pain is multifactorial, with various classification systems and treatment options. Classifying patients and grouping interventions in clinically relevant treatment nodes for a NMA is essential, but this process is poorly defined. OBJECTIVE: Our aim is to obtain consensus among experts on neck pain classifications and the grouping of interventions into nodes for a future network meta-analysis. DESIGN: A Delphi consensus study involving neck pain experts worldwide. METHODS: We invited authors of neck pain clinical practice guidelines published from 2014 onwards. The Delphi baseline questionnaire was developed based on the findings of a scoping review, including four items on classifications and 19 nodes. Participants were asked to record their level of agreement on a seven-point Likert scale or using Yes/No/Not sure answer options for the various statements. We used descriptive analysis to summarise the responses on each statement with content analysis of the free-text comments. RESULTS: In total, 18/80 experts (22.5%) agreed to participate in one or more Delphi rounds. We needed three rounds to reach consensus for two classification of neck pain: one based on aetiology and one on duration. In addition, we also reached consensus on the grouping of interventions, including a definition of each node, with the number of nodes reduced to 17. CONCLUSION: With this consensus we clinically validated two neck pain classifications and grouped conservative treatments into 17 well-defined and clinically relevant nodes.

Description of massage interventions in randomised clinical trials for neck pain; a review using the TIDieR checklist.

OBJECTIVE: How interventions are reported can impact the ability to implement these intervention in clinical practice. Therefore, our aim is to assess the reporting of massage interventions in randomised controlled trials for patients with neck pain. DATA SOURCES: This manuscript concerns a secondary analysis of trials evaluating massage for neck pain selected for a scoping review. An updated literature search was completed using four databases to 31 July 2023. REVIEW METHODS: Trials were selected that evaluate massage interventions. Two independent assessors extracted descriptive information, methodological quality (PEDro-scale) and assessed completeness of reporting of the intervention using the Template for Intervention Description and Replication (TIDier-checklist). We present frequencies of the extracted data. RESULTS: We included 35 trials (2840 patients) with neck pain. Most trials (n = 23) included patients with chronic non-specific neck pain. We found a wide variety of massage interventions from Chinese massage, Swedish massage to myofascial release. In addition, the dose, number of sessions and the duration of the intervention varied widely. The methodological quality overall was fair to good (varied between 4-8/10), and we found a moderate completeness of reporting. All trials provided the name of the intervention, 30 (86%) provided a rationale and 26 (74%) trials described details of the massage intervention. CONCLUSION: The massage interventions were moderately described in trials in patients with neck pain, but provided enough information to guide the decision making for designing future Network Meta-analysis as to what trials need to be considered when grouping massage interventions in a clinically relevant way.

Treatment classifications and interventions for neck pain: a scoping review.

OBJECTIVES: Our aim is to provide an overview of how neck pain is classified in the literature, define and group conservative interventions into 'nodes', and develop draft networks of interventions in preparation for a network meta-analysis (NMA). STUDY DESIGN AND SETTINGS: We performed a scoping review. For feasibility reasons, we searched for randomized clinical trials (RCTs) via neck pain clinical practice guidelines (CPGs) published from 2014. We used standardized data extraction forms to extract data about classification of neck pain and interventions evaluated in the included RCTs. We calculated frequencies of neck pain classifications and grouped interventions into nodes based on the definitions used in Cochrane reviews. Draft network graphs comparing interventions were constructed using the online Shiny R application CINEMA. RESULTS: We included 242 RCTs from seven CPGs, evaluating 28,581 patients. We found three different classification systems of which The Neck Pain Task Force classification was used most often. We defined and grouped all interventions into 19 discrete potential nodes. CONCLUSION: We found a wide variation in neck pain classifications and conservative interventions. Grouping the interventions was challenging and needs further evaluation before conducting a final NMA.

Feasibility of an Audit and Feedback Intervention to Facilitate Journal Policy Change Towards Greater Promotion of Transparency and Openness in Sports Science Research.

OBJECTIVES: To evaluate (1) the feasibility of an audit-feedback intervention to facilitate sports science journal policy change, (2) the reliability of the Transparency of Research Underpinning Social Intervention Tiers (TRUST) policy evaluation form, and (3) the extent to which policies of sports science journals support transparent and open research practices. METHODS: We conducted a cross-sectional, audit-feedback, feasibility study of transparency and openness standards of the top 38 sports science journals by impact factor. The TRUST form was used to evaluate journal policies support for transparent and open research practices. Feedback was provided to journal editors in the format of a tailored letter. Inter-rater reliability and agreement of the TRUST form was assessed using intraclass correlation coefficients and the standard error of measurement, respectively. Time-based criteria, fidelity of intervention delivery and qualitative feedback were used to determine feasibility. RESULTS: The audit-feedback intervention was feasible based on the time taken to rate journals and provide tailored feedback. The mean (SD) score on the TRUST form (range 0-27) was 2.05 (1.99), reflecting low engagement with transparent and open practices. Inter-rater reliability of the overall score of the TRUST form was moderate [ICC (2,1) = 0.68 (95% CI 0.55-0.79)], with standard error of measurement of 1.17. However, some individual items had poor reliability. CONCLUSION: Policies of the top 38 sports science journals have potential for improved support for transparent and open research practices. The feasible audit-feedback intervention developed here warrants large-scale evaluation as a means to facilitate change in journal policies. REGISTRATION: OSF ( https://osf.io/d2t4s/ ).

Comparison between 2000 and 2018 on the reporting of statistical significance and clinical relevance in physiotherapy clinical trials in six major physiotherapy journals: a meta-research design.

DESIGN: Meta-research. OBJECTIVE: To compare the prevalence of reporting p values, effect estimates and clinical relevance in physiotherapy randomised controlled trials (RCTs) published in the years 2000 and 2018. METHODS: We performed a meta-research study of physiotherapy RCTs obtained from six major physiotherapy peer-reviewed journals that were published in the years 2000 and 2018. We searched the databases Embase, Medline and PubMed in May 2019, and extracted data on the study characteristics and whether articles reported on statistical significance, effect estimates and confidence intervals for baseline, between-group, and within-group differences, and clinical relevance. Data were presented using descriptive statistics and inferences were made based on proportions. A 20% difference between 2000 and 2018 was regarded as a meaningful difference. RESULTS: We found 140 RCTs: 39 were published in 2000 and 101 in 2018. Overall, there was a high prevalence (>90%) of reporting p values for the main (between-group) analysis, with no difference between years. Statistical significance testing was frequently used for evaluating baseline differences, increasing from 28% in 2000 to 61.4% in 2018. The prevalence of reporting effect estimates, CIs and the mention of clinical relevance increased from 2000 to 2018 by 26.6%, 34% and 32.8% respectively. Despite an increase in use in 2018, over 40% of RCTs failed to report effect estimates, CIs and clinical relevance of results. CONCLUSION: The prevalence of using p values remains high in physiotherapy research. Although the proportion of reporting effect estimates, CIs and clinical relevance is higher in 2018 compared to 2000, many publications still fail to report and interpret study findings in this way.

Development and measurement properties of the AxEL (attitude toward education and advice for low-back-pain) questionnaire.

INTRODUCTION: Clinician time and resources may be underutilised if the treatment they offer does not match patient expectations and attitudes. We developed a questionnaire (AxEL-Q) to guide clinicians toward elements of first-line care that are pertinent to their patients with low back pain. METHODS: We used guidance from the COSMIN consortium to develop the questionnaire and evaluated it in a sample of people with low back pain of any duration. Participants were recruited from the community, were over 18 years and fluent in English. Statements that represented first-line care were identified. Semantic scales were used to measure attitude towards these statements. These items were combined to develop the questionnaire draft. Construct validity was evaluated with exploratory factor analysis and hypotheses testing, comparing to the Back Beliefs Questionnaire and modified Pain Self-Efficacy Questionnaire. Reliability was evaluated and floor and ceiling effects calculated. RESULTS: We recruited 345 participants, and had complete data for analysis for 313 participants. The questionnaire draft was reduced to a 3-Factor questionnaire through exploratory factor analysis. Factor 1 comprised 9 items and evaluated Attitude toward staying active, Factor 2 comprised 4 items and evaluated Attitude toward low back pain being rarely caused by a serious health problem, Factor 3 comprised 4 items and evaluated Attitude toward not needing to know the cause of back pain to manage it effectively. There was a strong inverse association between each factor and the Back Beliefs Questionnaire and a moderate positive association with the modified Pain Self-Efficacy Questionnaire. Each independent factor demonstrated acceptable internal consistency; Cronbach α Factor 1 = 0.92, Factor 2 = 0.91, Factor 3 = 0.90 and adequate interclass correlation coefficients; Factor 1 = 0.71, Factor 2 = 0.73, Factor 3 = 0.79. CONCLUSION: This study demonstrates acceptable construct validity and reliability of the AxEL-Q, providing clinicians with an insight into the likelihood of patients following first-line care at the outset.

Producing Clinically Meaningful Reductions in Disability: A Causal Mediation Analysis of a Patient Education Intervention.

Patient education is recommended as first-line care for low back pain (LBP), although its efficacy for providing clinically meaningful reductions in disability has been questioned. One way to improve treatment effects is to identify and improve targeting of treatment mechanisms. We conducted a pre-planned causal mediation analysis of a randomized, placebo-controlled trial investigating the effectiveness of patient education for patients with acute LBP. 202 patients who had fewer than six-weeks' duration of LBP and were at high-risk of developing chronic LBP completed two, one-hour treatment sessions of either intensive patient education, or placebo patient education. 189 participants provided data for the outcome self-reported disability at three-months and the mediators, pain self-efficacy, pain catastrophizing, and back beliefs at one-week post treatment. This causal mediation analysis found that pain catastrophizing (mediated effect, -0.64; 95% Confidence Interval [CI], -1.31 to -0.15) and back beliefs (mediated effect, -0.51; 95% CI, -1.15 to -0.02) partly explained the effect of patient education on disability but pain self-efficacy did not (mediated effect, -0.40; 95% CI -1.13 to 0.28). Considering the mediator-outcome relationship, patient education would need to induce an 8 point difference on the pain self-efficacy questionnaire (0-60); an 11 point difference on the back beliefs questionnaire (9-45); and a 21 point difference on the pain catastrophizing scale (0-52) to achieve a minimally clinically important difference of 2 points on the Roland Morris Disability Questionnaire (0-24). PERSPECTIVE: Understanding the mechanisms of patient education can inform how this treatment can be adapted to provide clinically meaningful reductions in disability. Our findings suggest that adapting patient education to better target back beliefs and pain self-efficacy could result in clinically meaningful reductions in disability whereas the role of pain catastrophizing in acute LBP is less clear.

Feeling reassured after a consultation does not reduce disability or healthcare use in people with acute low back pain: a mediation analysis of a randomised trial.

QUESTION: Does feeling reassured after a consultation reduce future disability or healthcare use in people with acute low back pain (LBP)? DESIGN: Mediation analysis of a randomised, sham-controlled trial. PARTICIPANTS: Two hundred and two people with acute LBP at above average risk (high risk) of developing chronic LBP. INTERVENTION: All participants received guideline-based care from their usual clinician. Participants received two additional 1-hour sessions of patient education focused on emphasising the benign nature of LBP or sham patient education that included active listening only. OUTCOME MEASURES: The two primary outcomes for this study were self-reported disability and healthcare use. The mediator was feeling reassured that LBP was not caused by serious illness. RESULTS: Data from 194 (96%) participants and 178 (88%) participants were included in the analysis for disability and healthcare use outcome models, respectively. Feeling reassured did not mediate the effect of the intervention on disability (indirect effect -0.23, 95% CI -0.71 to 0.18) or healthcare use (indirect effect 0.00, 95% CI -0.04 to 0.04). Patient education intervention increased feeling reassured (1.14 points, 95% CI 0.43 to 1.85) compared with sham patient education. However, the mediator (ie, feeling reassured) did not reduce disability (-0.20 points, 95% CI -0.58 to 0.19) or healthcare use (OR 1.09, 95% CI 0.98 to 1.21). CONCLUSION: Feeling reassured after a consultation did not lead to improvements in disability and healthcare use for people with acute LBP. Clinicians should reflect on the time that they allocate to reassuring their patients and consider reallocating time to other aspects of the consultation that could reduce disability and future healthcare use. TRIAL REGISTRATION: ACTRN12612001180808, study protocol https://osf.io/4tfaz/.

Intact tactile anisotropy despite altered hand perception in complex regional pain syndrome: rethinking the role of the primary sensory cortex in tactile and perceptual dysfunction.

Complex Regional Pain Syndrome (CRPS) is characterised by pain, autonomic, sensory and motor abnormalities. It is associated with changes in the primary somatosensory cortex (S1 representation), reductions in tactile sensitivity (tested by two-point discrimination), and alterations in perceived hand size or shape (hand perception). The frequent co-occurrence of these three phenomena has led to the assumption that S1 changes underlie tactile sensitivity and perceptual disturbances. However, studies underpinning such a presumed relationship use tactile sensitivity paradigms that involve the processing of both non-spatial and spatial cues. Here, we used a task that evaluates anisotropy (i.e., orientation-dependency; a feature of peripheral and S1 representation) to interrogate spatial processing of tactile input in CRPS and its relation to hand perception. People with upper limb CRPS (n = 14) and controls with (n = 15) or without pain (n = 19) judged tactile distances between stimuli-pairs applied across and along the back of either hand to provide measures of tactile anisotropy. Hand perception was evaluated using a visual scaling task and questionnaires. Data were analysed with generalised estimating equations. Contrary to our hypotheses, tactile anisotropy was bilaterally preserved in CRPS, and the magnitude of anisotropic perception bias was comparable between groups. Hand perception was distorted in CRPS but not related to the magnitude of anisotropy or bias. Our results suggest against impairments in spatial processing of tactile input, and by implication S1 representation, as the cause of distorted hand perception in CRPS. Further work is warranted to elucidate the mechanisms of somatosensory dysfunction and distorted hand perception in CRPS.

Think twice before starting a new trial; what is the impact of recommendations to stop doing new trials?

OBJECTIVES: In evidence-based medicine, we base our conclusions on the effectiveness of interventions on the results of high-quality meta-analysis. If a new randomized controlled trial (RCT) is unlikely to change the pooled effect estimate, conducting the new trial is a waste of resources. We evaluated whether recommendations not to conduct further RCTs reduced the number of trials registered for two scenarios. METHODS: Analysis of registered trials on the World Health Organisation (WHO) International Clinical Trials Registry Platform (ICTRP). We regarded trial protocols relevant if they evaluated the effectiveness of (1) exercise for chronic low back pain (LBP) and (2) cognitive behavioural therapy (CBT) for chronic pain. We calculated absolute and relative numbers and change of registered trials in a pre-set time window before and after publication of the recommendations, both published in 2012. RESULTS: We found 1,574 trials registered in the WHO trial registry for exercise in LBP (459 before 2012; 1,115 after) and 5,037 trials on chronic pain (1,564 before 2012; 3,473 after). Before 2012, 13 trials on exercise for LBP (out of 459) fit the selection criteria, compared to 42 trials (out of 1,115) after, which represents a relative increase of 33%. Twelve trials (out of 1,564) regarding CBT for chronic pain, fit the selection criteria before 2012 and 18 trials (out of 3,473) after, representing a relative decrease of 32%. We found that visibility, media exposure and strength of the recommendation were related to a decrease in registered trials. CONCLUSIONS: Recommendations not to conduct further RCTs might reduce the number of trials registered if these recommendations are strongly worded and combined with social media attention.

Pain Education for Adolescents and Young Adults Living Beyond Cancer: An Interdisciplinary Meeting Report.

Pain is an understudied and undertreated consequence of cancer survival. Pain education is now a recommended treatment approach for persistent non-cancer pain, yet it has not been well applied to the context of adolescent and young adult (AYA) cancer survival. In March 2018, an interdisciplinary meeting was held in Adelaide, South Australia to set a research agenda for pain education in AYA cancer survivors. We identified that AYAs with persistent pain and those with heightened pain-related fear have the potential to benefit from pain education. We identified a number of unique challenges of engaging AYA survivors in pain education, and point towards future research directions.

Effect of Intensive Patient Education vs Placebo Patient Education on Outcomes in Patients With Acute Low Back Pain: A Randomized Clinical Trial.

Importance: Many patients with acute low back pain do not recover with basic first-line care (advice, reassurance, and simple analgesia, if necessary). It is unclear whether intensive patient education improves clinical outcomes for those patients already receiving first-line care. Objective: To determine the effectiveness of intensive patient education for patients with acute low back pain. Design, Setting, and Participants: This randomized, placebo-controlled clinical trial recruited patients from general practices, physiotherapy clinics, and a research center in Sydney, Australia, between September 10, 2013, and December 2, 2015. Trial follow-up was completed in December 17, 2016. Primary care practitioners invited 618 patients presenting with acute low back pain to participate. Researchers excluded 416 potential participants. All of the 202 eligible participants had low back pain of fewer than 6 weeks' duration and a high risk of developing chronic low back pain according to Predicting the Inception of Chronic Pain (PICKUP) Tool, a validated prognostic model. Participants were randomized in a 1:1 ratio to either patient education or placebo patient education. Interventions: All participants received recommended first-line care for acute low back pain from their usual practitioner. Participants received additional 2 × 1-hour sessions of patient education (information on pain and biopsychosocial contributors plus self-management techniques, such as remaining active and pacing) or placebo patient education (active listening, without information or advice). Main Outcomes and Measures: The primary outcome was pain intensity (11-point numeric rating scale) at 3 months. Secondary outcomes included disability (24-point Roland Morris Disability Questionnaire) at 1 week, and at 3, 6, and 12 months. Results: Of 202 participants randomized for the trial, the mean (SD) age of participants was 45 (14.5) years and 103 (51.0%) were female. Retention rates were greater than 90% at all time points. Intensive patient education was not more effective than placebo patient education at reducing pain intensity (3-month mean [SD] pain intensity: 2.1 [2.4] vs 2.4 [2.2]; mean difference at 3 months, -0.3 [95% CI, -1.0 to 0.3]). There was a small effect of intensive patient education on the secondary outcome of disability at 1 week (mean difference, -1.6 points on a 24-point scale [95% CI, -3.1 to -0.1]) and 3 months (mean difference, -1.7 points, [95% CI, -3.2 to -0.2]) but not at 6 or 12 months. Conclusions and Relevance: Adding 2 hours of patient education to recommended first-line care for patients with acute low back pain did not improve pain outcomes. Clinical guideline recommendations to provide complex and intensive support to high-risk patients with acute low back pain may have been premature. Trial Registration: Australian Clinical Trial Registration Number: 12612001180808.

The reliability of eyetracking to assess attentional bias to threatening words in healthy individuals.

Eyetracking is commonly used to investigate attentional bias. Although some studies have investigated the internal consistency of eyetracking, data are scarce on the test-retest reliability and agreement of eyetracking to investigate attentional bias. This study reports the test-retest reliability, measurement error, and internal consistency of 12 commonly used outcome measures thought to reflect the different components of attentional bias: overall attention, early attention, and late attention. Healthy participants completed a preferential-looking eyetracking task that involved the presentation of threatening (sensory words, general threat words, and affective words) and nonthreatening words. We used intraclass correlation coefficients (ICCs) to measure test-retest reliability (ICC > .70 indicates adequate reliability). The ICCs(2, 1) ranged from -.31 to .71. Reliability varied according to the outcome measure and threat word category. Sensory words had a lower mean ICC (.08) than either affective words (.32) or general threat words (.29). A longer exposure time was associated with higher test-retest reliability. All of the outcome measures, except second-run dwell time, demonstrated low measurement error (<6%). Most of the outcome measures reported high internal consistency (α > .93). Recommendations are discussed for improving the reliability of eyetracking tasks in future research.

A randomized, placebo-controlled trial of patient education for acute low back pain (PREVENT Trial): statistical analysis plan.

BACKGROUND: Statistical analysis plans increase the transparency of decisions made in the analysis of clinical trial results. The purpose of this paper is to detail the planned analyses for the PREVENT trial, a randomized, placebo-controlled trial of patient education for acute low back pain. RESULTS: We report the pre-specified principles, methods, and procedures to be adhered to in the main analysis of the PREVENT trial data. The primary outcome analysis will be based on Mixed Models for Repeated Measures (MMRM), which can test treatment effects at specific time points, and the assumptions of this analysis are outlined. We also outline the treatment of secondary outcomes and planned sensitivity analyses. We provide decisions regarding the treatment of missing data, handling of descriptive and process measure data, and blinded review procedures. CONCLUSIONS: Making public the pre-specified statistical analysis plan for the PREVENT trial minimizes the potential for bias in the analysis of trial data, and in the interpretation and reporting of trial results. TRIAL REGISTRATION: ACTRN12612001180808 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12612001180808).

An embedded randomised controlled trial of a Teaser Campaign to optimise recruitment in primary care.

BACKGROUND: Marketing communication and brand identity is a fundamental principle of advertising and end-user engagement. Health researchers have begun to apply this principle to trial recruitment in primary care. The aim of this study was to evaluate whether a Teaser Campaign using a series of postcards in advance of a conventional mail-out increases the number of primary care clinics that engage with a clinical trial. METHODS: Embedded randomised recruitment trial across primary care clinics (general practitioners and physiotherapists) in the Sydney metropolitan area. Clinics in the Teaser Campaign group received a series of branded promotional postcards in advance of a standard letter inviting them to participate in a clinical trial. Clinics in the Standard Mail group did not receive the postcards. RESULTS: From a total of 744 clinics that were sent an invitation letter, 46 clinics in the Teaser Campaign group and 40 clinics in the Standard Mail group responded (11.6% total response rate). There was no between-group difference in the odds of responding to the invitation letter (odds ratio = 1.18, 95% confidence interval = 0.75-1.85, p = 0.49). For physiotherapy clinics and general practice clinics, the odds ratios were 1.43 (confidence interval = 0.82-2.48, p = 0.21) and 0.77 (confidence interval = 0.34-1.75, p = 0.54), respectively. CONCLUSION: A Teaser Campaign using a series of branded promotional postcards did not improve clinic engagement for a randomised controlled trial in primary care.

What you wear does not affect the credibility of your treatment: A blinded randomized controlled study.

OBJECTIVE: Professional appearance is easily modifiable, and might alter the effects of a clinical encounter. We aimed to determine whether professional attire influences a patient's perception of treatment credibility. METHODS: We performed a single-blind randomized controlled study on 128 patients with acute non-specific low back pain who were about to receive treatment in primary care. The treating clinician was randomly allocated to wear formal attire (experimental condition) or casual attire (control condition) to the consultation. Clinicians provided a standardized briefing on the rationale behind the patient's forthcoming treatment. Treatment credibility (Credibility and Expectancy Questionnaire) was assessed immediately after this briefing. RESULTS: All patients received the experimental or control condition as allocated and provided complete primary outcome data. Formal attire had no effect on perceived treatment credibility (Mean difference between groups 1.2 [95%CI-1.1 to 3.5]). Age was the only significant predictor of treatment credibility; older patients rated treatment credibility higher (Beta=0.16 [95%CI 0.08 to 0.24]). CONCLUSION: In a trial setting, whether or not a clinician is formally dressed has no effect on perceptions of treatment credibility in patients with acute low back pain. PRACTICE IMPLICATION: Clinicians should dress comfortably without fear of losing credibility.

Understanding how pain education causes changes in pain and disability: protocol for a causal mediation analysis of the PREVENT trial.

INTRODUCTION: Pain education is a complex intervention developed to help clinicians manage low back pain. Although complex interventions are usually evaluated by their effects on outcomes, such as pain or disability, most do not directly target these outcomes; instead, they target intermediate factors that are presumed to be associated with the outcomes. The mechanisms underlying treatment effects, or the effect of an intervention on an intermediate factor and its subsequent effect on outcome, are rarely investigated in clinical trials. This leaves a gap in the evidence for understanding how treatments exert their effects on outcomes. Mediation analysis provides a method for identifying and quantifying the mechanisms that underlie interventions. AIM: To determine whether the effect of pain education on pain and disability is mediated by changes in self-efficacy, catastrophisation and back pain beliefs. DESIGN: Causal mediation analysis of the PREVENT randomised controlled trial. PARTICIPANTS AND SETTING: Two hundred and two participants with acute low back pain from primary care clinics in the Sydney metropolitan area. INTERVENTION: Participants will be randomised to receive either 'pain education' (intervention group) or 'sham education' (control group). MEASUREMENTS: All outcome measures (including patient characteristics), primary outcome measures (pain and disability), and putative mediating variables (self-efficacy, catastrophisation and back pain beliefs) will be measured prior to randomisation. Putative mediators and primary outcome measures will be measured 1 week after the intervention, and primary outcome measures will be measured 3 months after the onset of low back pain. ANALYSIS: Causal mediation analysis under the potential outcomes framework will be used to test single and multiple mediator models. A sensitivity analysis will be conducted to evaluate the robustness of the estimated mediation effects on the influence of violating sequential ignorability--a critical assumption for causal inference. DISCUSSION AND SIGNIFICANCE: Mediation analysis of clinical trials can estimate how much the total effect of the treatment on the outcome is carried through an indirect path. Using mediation analysis to understand these mechanisms can generate evidence that can be used to tailor treatments and optimise treatment effects. In this study, the causal mediation effects of a pain education intervention for acute non-specific low back pain will be estimated. This knowledge is critical for further development and refinement of interventions for conditions such as low back pain.

Pain education to prevent chronic low back pain: a study protocol for a randomised controlled trial.

INTRODUCTION: Low back pain (LBP) is the leading cause of disability worldwide. Of those patients who present to primary care with acute LBP, 40% continue to report symptoms 3 months later and develop chronic LBP. Although it is possible to identify these patients early, effective interventions to improve their outcomes are not available. This double-blind (participant/outcome assessor) randomised controlled trial will investigate the efficacy of a brief educational approach to prevent chronic LBP in 'at-risk' individuals. METHODS/ANALYSIS: Participants will be recruited from primary care practices in the Sydney metropolitan area. To be eligible for inclusion participants will be aged 18-75 years, with acute LBP (<4 weeks' duration) preceded by at least a 1 month pain-free period and at-risk of developing chronic LBP. Potential participants with chronic spinal pain and those with suspected serious spinal pathology will be excluded. Eligible participants who agree to take part will be randomly allocated to receive 2×1 h sessions of pain biology education or 2×1 h sessions of sham education from a specially trained study physiotherapist. The study requires 101 participants per group to detect a 1-point difference in pain intensity 3 months after pain onset. Secondary outcomes include the incidence of chronic LBP, disability, pain intensity, depression, healthcare utilisation, pain attitudes and beliefs, global recovery and recurrence and are measured at 1 week post-intervention, and at 3, 6 and 12 months post LBP onset. ETHICS/DISSEMINATION: Ethical approval was obtained from the University of New South Wales Human Ethics Committee in June 2013 (ref number HC12664). Outcomes will be disseminated through publication in peer-reviewed journals and presentations at international conference meetings. TRIAL REGISTRATION NUMBER: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12612001180808.