Critical appraisal of clinical prediction rules that aim to optimize treatment selection for musculoskeletal conditions

Do various baseline characteristics of transversus abdominis and lumbar multifidus predict clinical outcomes in nonspecific low back pain? A systematic review

Although individual reports suggest that baseline morphometry or activity of transversus abdominis or lumbar multifidus predict clinical outcome of low back pain (LBP), a related systematic review is unavailable. Therefore, this review summarized evidence regarding the predictive value of these muscular characteristics. Candidate publications were identified from 6 electronic medical databases. After review, 5 cohort studies were included. Although this review intended to encompass studies using different muscle assessment methods, all included studies coincidentally used ultrasound imaging. No research investigated the relation between static morphometry and clinical outcomes. Evidence synthesis showed limited evidence supporting poor baseline transversus abdominis contraction thickness ratio as a treatment effect modifier favoring motor control exercise. Limited evidence supported that high baseline transversus abdominis lateral slide was associated with higher pain intensity after various exercise interventions at 1-year follow-up. However, there was limited evidence for the absence of relation between the contraction thickness ratio of transversus abdominis or anticipatory onset of lateral abdominal muscles at baseline and the short- or long-term LBP intensity after exercise interventions. There was conflicting evidence for a relation between baseline percent thickness change of lumbar multifidus during contraction and the clinical outcomes of patients after various conservative treatments. Given study heterogeneity, the small number of included studies and the inability of conventional greyscale B-mode ultrasound imaging to measure muscle activity, our findings should be interpreted with caution. Further large-scale prospective studies that use appropriate technology (ie, electromyography to assess muscle activity) should be conducted to investigate the predictive value of morphometry or activity of these muscles with respect to LBP-related outcomes measures.

Interpretation of subgroup effects in published trials

With the rapidly expanding number of studies reporting on treatment subgroups come new challenges in analyzing and interpreting this sometimes complex area of the literature. This article discusses 3 important issues regarding the analysis and interpretation of existing trials or systematic reviews that report on treatment effect modifiers (subgroups) for specific physical therapy interventions. The key messages are: (1) point estimates of treatment modifier effect size (interaction effect) and their confidence intervals can be calculated using group-level data when individual patient-level data are not available; (2) interaction effects do not define the total effect size of the intervention in the subgroup but rather how much more effective it is in the subgroup than in those not in the subgroup; (3) recommendations regarding the use of an intervention in a subgroup need to consider the size and direction of the main effect and the interaction effect; and (4) rather than simply judging whether a treatment modifier effect is clinically important based only on the interaction effect size, a better criterion is to determine whether the combined effect of the interaction effect and main effect makes the difference between an overall effect that is clinically important and one that is not clinically important.

Effectiveness of mechanical diagnosis and therapy in patients with back pain who meet a clinical prediction rule for spinal manipulation

Recently a clinical prediction rule (CPR) for lumbar regional spinal thrust manipulation (STM) has shown predictive success in patients with back pain who met specific selection criteria. The purpose of this study was to compare the effectiveness of STM and mechanical diagnosis and therapy (MDT) in patients who are positive for the STM CPR. Following initial examination, 31 participants were randomized to the STM group (n = 16) and to the MDT group (n = 15). Two weeks following initial examination, four participants chose to cross over from the STM group to the MDT group. The Oswestry Disability Index (ODI), Fear-Avoidance Beliefs Questionnaire work subscale (FABQw), and the Numerical Pain Rating Scale (NPRS) were administered initially, and at 2-weeks and 4 week follow-up (discharge). Data were analyzed to determine changes in ODI and NPRS scores from initial examination through one month. Of the 31 participants, one patient who met only three of five selection criteria and four others who chose to switch groups were removed from the analysis. Both groups exhibited statistically significant improvements in ODI and NPRS scores from baseline to final visit but there was no significant difference in scores between groups at 4 weeks. In this sample of patients, the selection criteria for this CPR were not exclusive for lumbopelvic STM. Mechanical diagnosis and therapy was an equally viable choice for these patients.

Primary care research priorities in low back pain: an update

STUDY DESIGN

Survey report.

OBJECTIVE

To reassess an existing list of research priorities in primary care low back pain (LBP) and to develop a new research agenda.

SUMMARY OF BACKGROUND DATA

Primary care LBP researchers developed an agenda of research priorities in 1997 at an international conference. In 2009, a survey was conducted to re-evaluate the 1997 research priorities and to develop a new research agenda.

METHODS

Two-phase, Internet-based survey of participants in one of the LBP primary care research fora. The first phase collected information on importance, feasibility, and progress for the 1997 priorities; during this phase, the respondents were also asked to list the 5 most important current primary care-relevant LBP research questions. The second phase ranked these current research priorities.

RESULTS

A total of 179 persons responded to the first phase, representing 30% of those surveyed. Rankings of the 1997 priorities were somewhat similar compared with 2009, although research on beliefs and expectations and improving the quality of LBP research became more important, and research on guidelines and psychosocial interventions became less important. Organizing more effective primary care for LBP, implementing best practices, and translating research to practice were ranked higher compared with 1997. Most priorities were also ranked as relatively feasible. The new agenda was similar, and included subgroup-based treatment and studies on causes and mechanisms of LBP as new top priorities.

CONCLUSION

Changes in research priorities seem to reflect recent advances, new opportunities, and limitations in our ability to improve care.

Which prognostic factors for low back pain are generic predictors of outcome across a range of recovery domains?

BACKGROUND

Recovery from low back pain (LBP) is multidimensional and requires the use of multiple-response (outcome) measures to fully reflect these many dimensions. Predictive prognostic variables that are present or stable in all or most predictive models that use different outcome measures could be considered "universal" prognostic variables.

OBJECTIVE

The aim of this study was to explore the potential of universal prognostic variables in predictive models for 4 different outcome measures in patients with mechanical LBP.

DESIGN

Predictive modeling was performed using data extracted from a randomized controlled trial. Four prognostic models were created using backward stepwise deletion logistic, Poisson, and linear regression.

METHODS

Data were collected from 16 outpatient physical therapy facilities in 10 states. All 149 patients with LBP were treated with manual therapy and spine strengthening exercises until discharge. Four different measures of response were used: Oswestry Disability Index and Numeric Pain Rating Scale change scores, total visits, and report of rate of recovery.

RESULTS

The set of statistically significant predictors was dependent on the definition of response. All regression models were significant. Within both forms of the 4 models, meeting the clinical prediction rule for manipulation at baseline was present in all 4 models, whereas no irritability at baseline and diagnosis of sprains and strains were present in 2 of 4 of the predictive models.

LIMITATIONS

The primary limitation is that this study evaluated only 4 of the multiple outcome measures that are pertinent for patients with LBP.

CONCLUSIONS

Meeting the clinical prediction rule was prognostic for all outcome measures and should be considered a universal prognostic predictor. Other predictive variables were dependent on the outcomes measure used in the predictive model.

Preliminary state of development of prediction models for primary care physical therapy: a systematic review

OBJECTIVE

To summarize the methodological quality and developmental stage of prediction models for musculoskeletal complaints that are relevant for physical therapists in primary care.

STUDY DESIGN AND SETTING

A systematic literature search was carried out in the databases of Medline, Embase, and Cinahl. Studies on prediction models for musculoskeletal complaints that can be used by primary care physical therapists were included. Methodological quality of the studies was assessed and relevant study characteristics were extracted.

RESULTS

The search retrieved 4,702 references of which 29 studies were included in this review. The study quality of the included studies showed substantial variation. The studied populations consisted mostly of back (n=10) and neck pain (n=6) patients, and patients with knee complaints (n=4). Most studies (n=22) used "perceived recovery" as primary outcome. Most prediction models (n=18) were at the derivation level of development.

CONCLUSIONS

Many prediction models are available for a wide range of patient populations. The developmental stage of most models is preliminary and the study quality is often moderate. We do not recommend physiotherapist to use these models yet. All models reviewed here are in the developmental stage and need validation and impact evaluation before using them in daily practice.

Clinical decision rules, spinal pain classification and prediction of treatment outcome: A discussion of recent reports in the rehabilitation literature

Clinical decision rules are an increasingly common presence in the biomedical literature and represent one strategy of enhancing clinical-decision making with the goal of improving the efficiency and effectiveness of healthcare delivery. In the context of rehabilitation research, clinical decision rules have been predominantly aimed at classifying patients by predicting their treatment response to specific therapies. Traditionally, recommendations for developing clinical decision rules propose a multistep process (derivation, validation, impact analysis) using defined methodology. Research efforts aimed at developing a "diagnosis-based clinical decision rule" have departed from this convention. Recent publications in this line of research have used the modified terminology "diagnosis-based clinical decision guide." Modifications to terminology and methodology surrounding clinical decision rules can make it more difficult for clinicians to recognize the level of evidence associated with a decision rule and understand how this evidence should be implemented to inform patient care. We provide a brief overview of clinical decision rule development in the context of the rehabilitation literature and two specific papers recently published in Chiropractic and Manual Therapies.

Pathoanatomy and classification of low back disorders

Over the past decade research into the effectiveness of low back disorders (LBDs) has focused on the classification of subgroups more likely to respond to specific treatment. Much of this research has explicitly excluded a focus on pathoanatomical factors based on a questionable interpretation of the biopsychosocial model. Common justifications and potential issues with this approach are explored with recommendations made for future clinical and research practice.

The efficacy of targeted interventions for modifiable psychosocial risk factors of persistent nonspecific low back pain - a systematic review

BACKGROUND

There is considerable interest in whether best practice management of nonspecific low back pain (NSLBP) should include the targeting of treatment to subgroups of people with identifiable clinical characteristics. However, there are no published systematic reviews of the efficacy of targeted psychosocial interventions.

AIM

This review aimed to determine if the efficacy of interventions for psychosocial risk factors of persistent NSLBP is improved when targeted to people with particular psychosocial characteristics.

METHOD

Bibliographic databases were searched. Inclusion criteria were randomised controlled trials of targeted psychosocial interventions that used trial designs capable of providing robust information on the efficacy of targeted treatment (treatment effect modification) for the outcomes of pain, activity limitation and psychosocial factors (fear avoidance, catastrophisation, anxiety and depression).

RESULTS AND CONCLUSION

Four studies met the inclusion criteria and collectively investigated nine hypotheses about targeted treatment on 28 subgroup/treatment outcomes. There were only two statistically significant results. Graded activity plus Treatment Based Classification targeted to people with high movement-related fear was more effective than Treatment Based Classification at reducing movement-related fear at 4 weeks. Active rehabilitation (physical exercise classes with cognitive-behavioural principles) was more effective than usual GP care at reducing activity limitation at 12 months, when targeted to people with higher movement-related pain. Few studies have investigated targeted psychosocial interventions in NSLBP, using trial designs suitable for measuring treatment effect modification, and they do not provide consistent evidence supporting such targeting. There is a need for appropriately designed and adequately powered trials to investigate targeted psychosocial interventions.

The effectiveness of sub-group specific manual therapy for low back pain: a systematic review

BACKGROUND

Manual therapy is frequently used to treat low back pain (LBP), but evidence of its effectiveness is limited. One explanation may be sample heterogeneity and inadequate sub-grouping of participants in randomized controlled trials (RCTs) where manual therapy has not been targeted toward those likely to respond.

OBJECTIVES

To determine the effectiveness of specific manual therapy provided to sub-groups of participants identified as likely to respond to manual therapy.

DATA SOURCES

A systematic search of electronic databases of MEDLINE, EMBASE, CINAHL, and the Cochrane Central Register of Controlled trials (CENTRAL). TRIAL ELIGIBILITY CRITERIA: RCTs on manual therapy for participants identified as belonging to a sub-group of LBP likely to respond to manual therapy were included. TRIAL APPRAISAL AND SYNTHESIS METHODS: Identified trials were assessed for eligibility. Data from included trials were extracted by two authors independently. Risk of bias in each trial was assessed using the PEDro scale and the overall quality of evidence rated according to the GRADE domains. Treatment effect sizes and 95% confidence intervals were calculated for pain and activity.

RESULTS

Seven RCTs were included in the review. Clinical and statistical heterogeneity precluded meta-analysis. Significant treatment effects were found favouring sub-group specific manual therapy over a number of comparison treatments for pain and activity at short and intermediate follow-up. However, the overall GRADE quality of evidence was very low.

CONCLUSIONS

This review found preliminary evidence supporting the effectiveness of sub-group specific manual therapy. Further high quality research on LBP sub-groups is required.

Optimal designs for prediction studies of whiplash

STUDY DESIGN

Commentary.

OBJECTIVE

To provide guidance for the design and interpretation of predictive studies of whiplash associated disorders (WAD).

SUMMARY OF BACKGROUND DATA

Numerous studies have sought to define and explain the clinical course and response to treatment of people with WAD. Design of these studies is often suboptimal, which can lead to biased findings and issues with interpreting the results.

METHODS

Literature review and commentary.

RESULTS

Predictive studies can be grouped into four broad categories; studies of symptomatic course, studies that aim to identify factors that predict outcome, studies that aim to isolate variables that are causally responsible for outcome, and studies that aim to identify patients who respond best to particular treatments. Although the specific research question will determine the optimal methods, there are a number of generic features that should be incorporated into design of such studies. The aim of these features is to minimize bias, generate adequately precise prognostic estimates, and ensure generalizability of the findings.

CONCLUSION

This paper provides a summary of important considerations in the design, conduct, and reporting of prediction studies in the field of whiplash.

Can we predict response to the McKenzie method in patients with acute low back pain? A secondary analysis of a randomized controlled trial

PURPOSE

To evaluate whether patients' treatment preferences, characteristics, or symptomatic response to assessment moderated the effect of the McKenzie method for acute low back pain (LBP).

METHODS

This study involved a secondary analysis of a previous RCT on the effect of adding the McKenzie method to the recommended first-line care for patients with acute non-specific LBP. 148 patients were randomized to the First-line Care Group (recommended first-line care alone) or the McKenzie Group (McKenzie method in addition to the first-line care) for a 3-week course of treatment. The primary outcome was pain intensity at 3 weeks. The ability of six patient characteristics to identify those who respond best to McKenzie method was assessed using interaction terms in linear regression models.

RESULTS

The six investigated potential effect modifiers for response to the McKenzie method did not predict a more favorable response to this treatment. None of the point estimates for effect modification met our pre-specified criterion of clinical importance of a 1 point greater improvement in pain. For five of the six predictors, the 95% CI did not include our criterion for meaningful clinical improvement.

CONCLUSION

We were unable to find any clinically useful effect modifiers for patients with acute LBP receiving the McKenzie method.

Prediction of persistent shoulder pain in general practice: comparing clinical consensus from a Delphi procedure with a statistical scoring system

Background

In prognostic research, prediction rules are generally statistically derived. However the composition and performance of these statistical models may strongly depend on the characteristics of the derivation sample. The purpose of this study was to establish consensus among clinicians and experts on key predictors for persistent shoulder pain three months after initial consultation in primary care and assess the predictive performance of a model based on clinical expertise compared to a statistically derived model.

Methods

A Delphi poll involving 3 rounds of data collection was used to reach consensus among health care professionals involved in the assessment and management of shoulder pain.

Results

Predictors selected by the expert panel were: symptom duration, pain catastrophizing, symptom history, fear-avoidance beliefs, coexisting neck pain, severity of shoulder disability, multisite pain, age, shoulder pain intensity and illness perceptions. When tested in a sample of 587 primary care patients consulting with shoulder pain the predictive performance of the two prognostic models based on clinical expertise were lower compared to that of a statistically derived model (Area Under the Curve, AUC, expert-based dichotomous predictors 0.656, expert-based continuous predictors 0.679 vs. 0.702 statistical model).

Conclusions

The three models were different in terms of composition, but all confirmed the prognostic importance of symptom duration, baseline level of shoulder disability and multisite pain. External validation in other populations of shoulder pain patients should confirm whether statistically derived models indeed perform better compared to models based on clinical expertise.

Clinical prediction rules in the physiotherapy management of low back pain: a systematic review

OBJECTIVE

To identify, appraise and determine the clinical readiness of diagnostic, prescriptive and prognostic Clinical Prediction Rules (CPRs) in the physiotherapy management of Low Back Pain (LBP).

DATA SOURCES

MEDLINE, EMBASE, CINAHL, AMED and the Cochrane Database of Systematic Reviews were searched from 1990 to January 2010 using sensitive search strategies for identifying CPR and LBP studies. Citation tracking and hand-searching of relevant journals were used as supplemental strategies.

STUDY SELECTION

Two independent reviewers used a two-phase selection procedure to identify studies that explicitly aimed to develop one or more CPRs involving the physiotherapy management of LBP. Diagnostic, prescriptive and prognostic studies investigating CPRs at any stage of their development, derivation, validation, or impact-analysis, were considered for inclusion using a priori criteria. 7453 unique records were screened with 23 studies composing the final included sample.

DATA EXTRACTION

Two reviewers independently extracted relevant data into evidence tables using a standardised instrument.

DATA SYNTHESIS

Identified studies were qualitatively synthesized. No attempt was made to statistically pool the results of individual studies. The 23 scientifically admissible studies described the development of 25 unique CPRs, including 15 diagnostic, 7 prescriptive and 3 prognostic rules. The majority (65%) of studies described the initial derivation of one or more CPRs. No studies investigating the impact phase of rule development were identified.

CONCLUSIONS

The current body of evidence does not enable confident direct clinical application of any of the identified CPRs. Further validation studies utilizing appropriate research designs and rigorous methodology are required to determine the performance and generalizability of the derived CPRs to other patient populations, clinicians and clinical settings.

Psychologically informed interventions for low back pain: an update for physical therapists

A central theme of current evidence-based guidelines for managing low back pain is endorsement of the resumption of activities despite the presence of pain. This task can be challenging for both therapists and patients, and there are many essentially psychological obstacles to implementing the guidelines. These obstacles can be overcome by knowing how to recognize potential psychological obstacles and understanding the options for managing psychological obstacles in combination with activity-based interventions. This article is intended to address these tasks by explaining and describing the application of empirically based psychological principles and strategic clinical reasoning. Importantly, the roles of skills in assessment, treatment planning, and communication with patients are identified as essential but feasible skills for physical therapists to acquire with appropriate training.