Clinical course, characteristics and prognostic indicators in patients presenting with back and leg pain in primary care. The ATLAS study protocol

(i) The primary aims of this study are: for patients presenting in primary care with low back and leg pain, managed according to currently agreed "best practice" and followed up for 12 months, to describe the clinical, imaging, demographic characteristics and health economic outcomes for the whole cohort, and to investigate differences between those classified with and without nerve root pain

and

(ii) to identify prognostic indicators of outcome (i.e. change in disability at 12 months), for the whole cohort and, separately for those classified with and without nerve root pain

Specific objectives include:

(a) identification of prognostic subgroups of patients with distinct trajectories of pain and disability over 12 month follow-up

(b) description of health care resource use and work productivity within and between those with LBP and non-specific leg pain, and those with a clinical diagnosis of LBP with nerve root pain over 12 months follow-up

(c) investigation of the effect of clinical assessment and treatment negotiation between physiotherapists and patients on decision-making

(d) examination of whether the classification of leg pain (eg. either with or without nerve root involvement) impacts on patients' symptom management, help seeking behaviour and illness trajectory

Primary care, multi-centre prospective observational cohort study

Adults aged 18 years and over consulting their General Practitioner (GP) with LBP and radiating leg pain of any duration at GP practices in North Staffordshire and Stoke-on-Trent, UK. Radiating leg pain is defined as pain spreading from the back beyond the gluteal fold to anywhere in the leg. In this context "pain" is taken to include all unpleasant/abnormal sensations such as 'pins and needles' or numbness.

• Persons with "red flags" indicative of possible serious spinal pathology

• Serious co-morbidity which prevents patients from being able to travel to the clinic and/or undergo a clinical assessment

• Patients with serious mental health problems who the GP considers to be vulnerable and for whom participation in the study would be detrimental

• Previous spinal surgery

• Pregnancy

• Currently receiving physiotherapy (or osteopathy, chiropractic) or under a secondary care consultant for the same problem

• Not able to read and speak English

Potentially eligible participants will be identified at the GP consultation and referred to a Community Low Back and Leg Pain Clinic where they will be invited to take part in the study. When a patient with back pain consults their GP, and the GP enters an appropriate Read Code on the computer system, a "pop-up" prompt screen will ask the GP if they think the patient has leg pain associated with their back problem, and if so to consider whether the patient is suitable to be invited to the Community Low Back and Leg Pain Clinic. The GP will have the facility to enter "yes" or "no" on the computer system to flag if patients are suitable or unsuitable for referral to the clinic. Whilst desirable, it is not imperative that the GP informs the patient about the clinic for example, if the GP enters the patient as suitable on the system but after the consultation has ended and the patient has left, the patient will still be invited through the process described below.

On a weekly basis West Midlands North Primary Care Research Network (WMN PCRN) staff will facilitate the mailing of letters to all patients who have been flagged as suitable. The letter will invite patients to telephone the clinic administrator to make an appointment at the clinic, it will explain that there is a research study being hosted at the clinic but that attendance at the clinic does not oblige them to take part. Patients who telephone the clinic administrator will be offered a clinic appointment within 10 working days. A letter will be sent to patients to confirm their appointment time--a study baseline questionnaire and patient information sheet will be enclosed with this letter. Approximately 2 days before the clinic, a clinic nurse will telephone patients to remind them about their appointment time and ask those who are interested in taking part in the research to bring their completed questionnaire.

There will also be a separate referral pathway to capture patients who contact PhysioDirect (Physiotherapy Direct Access Service), a community physiotherapy service allowing patients to telephone directly through to a physiotherapist without needing to first consult their GP. Following the usual PhysioDirect assessment, suitable patients will be asked whether they would be interested in being invited to the Community Low Back and Leg Pain Clinic. Referrals will be faxed to the research centre and a letter will be sent to the patient inviting them to telephone the clinic administrator to make an appointment for the clinic as described above.

See Additional file 1 for a flowchart of the study.

Physiotherapy assessment and management will be provided to all patients attending, irrespective of whether or not they are eligible or agree to take part in the study. The clinic will be operated as an integrated service/research clinic, with NHS treating clinicians being fully supported by WMN PCRN clinical and administrative staff working as a single team. At the clinic, a nurse will check potential eligibility and if the patient wishes to take part in the study gain signed informed consent. The study questionnaire which had been mailed to patients with their appointment letter will be received and checked and participants will be asked to complete a further brief baseline questionnaire during the clinic.

All study participants will receive a standardised assessment at the clinic by a study physiotherapist, at which full eligibility will be established by, for example, by excluding patients whose leg pain is not considered to be associated with their back pain (e.g. hip osteoarthritis). This standardised assessment has been developed following a Delphi study aimed at developing consensus on the content of the clinical assessment for adults presenting in primary care with low back-related leg pain [26]. Each eligible patient will be classified by the assessing physiotherapist as having LBP with referred leg pain or having LBP with nerve root pain ("reference standard" is the clinician's diagnosis). The content of the clinical assessment is provided in Additional file 2.

Clinical management will follow agreed care pathways, based on current best clinical evidence, practice guidelines and local services and resources. In addition to clinical examination findings simple self-reported clinical markers of severity and risk of poor outcome measured using the STarT Back tool [27], will be used as an adjunct to clinical judgment to direct patients' care. The patient's care pathway will be decided at the discretion of the treating clinician in consultation with the patient and in line with the agreed care pathways. This is a mixed stratified/stepped care approach and as such if a patient's symptoms deteriorate they can transfer to a pathway for patients with more severe symptoms. There will be three categories/groups according to symptoms severity and previous response to treatment for current episode.

Patients in this group are expected to have mild/improving symptoms and be classified at low risk of a poor outcome according to the STarT Back tool. Patients will receive a brief physiotherapy intervention (one or two sessions) according to their needs consisting of advice, education and home exercises. The physiotherapist will emphasise messages about promoting speedy return to normal activity, avoiding rest, appropriate use of pain relieving modalities (such as painkillers), and work issues. Patients will be encouraged to ask questions relating to any specific concerns about their back and leg pain. As appropriate to their presentation, patients will be given some written educational information--if it is suitable this may be the 'Back Book' [28], or patients with nerve root pain may be given more specific information relating to their condition. If appropriate/necessary patients will be given an information sheet containing local contacts for exercise venues such as swimming pools and gyms, exercise on prescription and self-help groups to facilitate activity and early return to work. Patients will have the option to contact the service again if symptoms persist or worsen.

Patients in this group are expected to have moderately severe pain and disability and most likely be at "moderate" or "high" risk of poor outcome according to the STarT Back tool. For those patients classified as 'moderate risk' of a poor outcome, the physiotherapist will negotiate an individualised treatment plan with the patient according to their need and best current evidence. The physiotherapist will address any worries or fears and unhelpful beliefs patients' may have about their back and leg pain, will emphasise messages as for group (i), and will use a range of pre-agreed physiotherapy techniques, including manual therapy and exercises where appropriate. For those patients classified as 'high risk' of a poor outcome, in addition to appropriate treatments for their back-related physical symptoms (e.g. pain), treatment may also include cognitive behavioural approaches specifically addressing the main psychosocial risk factors for chronicity (pain related fear about movement, catastrophising and pain-related depression).

The group (ii) intervention will be delivered in one 45-min session with a target of up to 6 further 30-min sessions (tailored according to clinical need) over 6-8 weeks. Pathways will be in place to refer patients that fail to improve or worsen to the dedicated Back Pain Service, for further assessment and management. The Back Pain Service is a pathway run by spinal physiotherapy specialists and there is access to and input from orthopaedic surgeons, pain clinic anaesthetists and rheumatologists as appropriate. Management of patients referred to the Back Pain Service will be at the discretion of the treating specialist, but may involve invasive procedures such as injections or surgery where indicated.

Patients in this group will have severe levels of back and leg pain-related symptoms with associated functional limitations, and/or progressive neurological symptoms or signs, with or without significant levels of psychological distress (they are expected to be classified as "moderate" or "high" risk of poor outcome according to the STarT Back tool), and are thus considered not appropriate for conservative primary care physiotherapy interventions and/or cognitive behavioural approaches. In addition Group (iii) may include patients in whom such treatments have been tried previously without any benefit. After the initial clinic assessment these patients will be referred directly to the dedicated Back Pain Service as described above.

Seven senior, experienced musculoskeletal physiotherapists will undertake 21/2 days training led by the study Principal Investigator (KK) and including sessions with a GP with special interest in musculoskeletal conditions (GPwSI MSK), a Rheumatologist, and a Consultant in Pain Management. The focus of the training is on carrying out the standardised assessment according to agreed protocols, and on equipping the physiotherapists to assess and target back pain, leg pain, co-morbid pain, disability and psychological risk factors for chronicity such as pain related distress, fear of movement, unhelpful beliefs and expectations. Emphasis is given on the differentiation between back pain with leg pain due to nerve root involvement and back pain with referred leg pain. The training includes the evidence-based assessment of LBP, including the use and interpretation of the STarT Back tool to guide treatment in addition to the role of diagnostic investigations (including understanding, interpretation and communication of MRI results to the patients and their GPs), medication, epidural injections and surgery in back pain and radiculopathy. Current guidelines for managing LBP in primary care will be discussed, including appropriate reassurance and advice about analgesia, the maintenance of, or return to, usual activities (including work) and patients who present a clinical or management concern (e.g. those with signs of potential serious pathology or red flags). The training includes current best physiotherapy practice for the management of disability, back pain and leg pain, including the role of exercise and manual therapy as well as strategies for equipping patients with the skills to manage future recurrences. Goal setting, pacing and graded exercise will also be covered.

The training will be supplemented by a comprehensive manual, providing clear guidelines and treatment algorithms for the evidence based assessment and treatment of patients with LBP, either with or without leg pain. Patients exhibiting many psychosocial risk factors for chronicity may be treated, if necessary, by physiotherapists that have already undergone extensive appropriate training in the context of our previous STarT Back trial [23, 29] and implementation study [30]. Continuous mentoring and supervision for the duration of the study will be provided by the Principal Investigator and the spinal physiotherapy specialists working in the Back Pain Service.

All participants will be invited for a Magnetic Resonance Imaging (MRI) scan, providing there are no contraindications, unless they have had an MRI scan in the past 6 months and their clinical presentation has not changed. MRI is the best available diagnostic imaging modality for LBP and leg pain as it provides excellent resolution of both nerve roots (allowing for assessment of nerve root compression) and bony structures. MRI is non-invasive for the patient and does not require any ionising radiation exposure. MRI will be performed using 1.5T magnetic resonance units. A body spine surface coil will used for imaging the lumbar region. Patients will undergo a standard lumbar spine MRI (including sagittal T1 and T2 weighted spin echo sequences and STIR sequences), similar to that undertaken in routine clinical practice. This will take approximately 30 min with the patient lying in the supine position in the scanner.

A summary report on the MRI scan will be provided by a Consultant Radiologist at the NHS Trust Hospital. The primary purpose for the MRI scan is to provide data for the research study (as opposed related to clinical need) and will be completed within 10 working days of the clinic appointment. However, any relevant clinical findings from the scan will be acted upon by the treating clinician. The patients and their GPs will be notified of the results as a matter of course.

Qualitative research methods will be used to address the study's specific objectives (c) and (d). This will involve a series of observations (approximately 30) during the standardised clinical assessments and subsequent treatment consultations, as well as interviews with a sample of patients (approximately 20). Consultations for observation and participants for interview will be selected 'opportunistically' from each of the three care pathways ensuring that a wide range of patients (in relation to age, sex, symptom severity, and social class) are included ('maximum diversification sample'). Observations will be conducted in person by a qualitative researcher using a topic guide in order to gain experiential insights and understanding of the consultation, the participants, and wider organisational influences. Researcher field notes will be supplemented with audio-recordings where participants have given consent.

Observations will empirically examine the treatment decision-making process, the involvement of patients in these decisions, and the role of symptom severity/duration on 'process' issues. We hypothesise that these issues could have a bearing on future patient outcomes, which will be examined in more detail during the patient interviews. The consultations will compare patients with and without a clinical diagnosis of 'nerve root involvement'. Observations will examine whether diagnostic status appears to influence the clinical decision making process of physiotherapists, and choices of treatment expressed by patients at different stages of treatment within each care pathway. Hence, observations will be conducted at various stages of treatment in order to explore whether the physiotherapist-patient interaction changes over time and the potential impact on patient 'concordance to the treatment intervention.

Patients will be invited to take part in the interview study following their consultation with a physiotherapist. Semi-structured qualitative interviews will be conducted using a topic guide to explore key themes systematically with all participants, but with emergent observations and insights from earlier findings feeding into subsequent interviews. This will allow examination of variation in perceptions between participants. Patients will be interviewed to explore: 1) patients' experiences of, and perceptions towards, decision-making with a physiotherapist, and 2) patients' illness trajectories and acceptability of the treatment plan. Interviews will specifically examine how patients' 'diagnostic status' (whether they receive a diagnosis of 'nerve root involvement' or not) affects their illness experience, pain management and help seeking behaviour.

The study outcomes will be collected at 4 and 12 months using postal self-complete questionnaires. Data will also be collected each month using brief postal questionnaires to enable detailed description of the course of low back and leg pain. Reminders will be sent to non-responders at 4 and 12-months.

The primary outcome for this study is disability at 12 months follow up as measured with the Roland and Morris Disability Questionnaire (RMDQ) leg pain version [31, 32]. Secondary outcomes include measures of pain intensity and trajectory, neuropathic pain, psychological constructs, work-related factors, general health perceptions and health care utilisation. Measures of disability, pain intensity, and work absence will be collected in the brief monthly questionnaires in order to describe the detailed course of the condition. Additional potential prognostic factors collected at baseline include, episode duration, pain location, clinical assessment findings (i.e. neurological examination findings), co-morbidity, smoking, height and weight (see Table 1 for details of measures and time points for data collection).

The study includes a health economic evaluation focusing both on a health care perspective and the wider societal perspective. A health care perspective addresses the direct health care costs incurred within both the public and private sectors. The societal perspective will incorporate the indirect costs of sickness absence and reduced productivity at work due to low back and/or leg pain. Health care use data will focus on key cost drivers including hospital attendances, surgery, inpatient stays, outpatient appointments and any other hospital visits to health care practitioners within the UK National Health Service (NHS) and private practice, consultations with NHS primary health care providers (e.g. general practitioner, practice nurse), prescribed medications, and over-the-counter treatments. This data will also capture resource use required to implement the care pathway. Unit costs assigned to these resources will be obtained from standard published sources reflecting UK national averages.

A recruited sample size of 500 patients will be sufficient to detect, with at least 80% power, a difference of 15% in the proportion of people with poor outcome, in relation to back-related disability, between the subgroups of leg pain patients with and without nerve root pain, assuming 20% loss to follow up and 5% two-tailed significance level. Poor outcome is defined as less than 30% change on RMDQ score [33]. This sample size is likely to be adequate for exploring the independent association of at least 15 prognostic indicators of outcome per subgroup (according to Altman's [34] guideline for restriction of the number of variables in a multiple regression). Based on findings from our previous observational and intervention studies of back pain we can assume a 6% prevalence of adults consulting their GP with LBP, of which about 60% will report leg pain, and of these the GP will invite approximately two-thirds to the community clinic. Of those invited we anticipate about 50% will attend, of which about two-thirds will be interested in taking part in the research study. We expect two-thirds of those who undergo the eligibility screening with the study nurse and physiotherapist will be suitable for the study. This means that approximately 1200 patients will need to be seen at the community clinic to recruit 500 participants to the cohort study, which requires a total GP practice population of about 90,000 adults, equivalent to about 12 average-sized practices in the WMN PCRN network.