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IntroductionThe treatment of back pain, and theconsequences of back pain-relateddisability, represent an enormous drainon social, economic and medicalresources (CSAG, 1994; Maniadakis and Gray, 2000). The cost to NHSphysiotherapy services of treating backpain has been conservatively estimated tobe £151 million per annum (Maniadakisand Gray, 2000). The report by theClinical Standards Advisory Group(CSAG, 1994) drew attention to the factthat much of the disability which resultsfrom chronic back pain is preventable,given appropriate advice and treatment in the early stages of the condition.

The move towards early intervention inacute back pain was given further impetusby the Yellow Flags assessment guidelines(CSAG, 1994; Watson and Kendall, 1999).These guidelines are based upon dataindicating that psychosocial variables arestronger predictors of pain-related dis-ability than are medical findings (Turk,

1997). Individuals deemed to be at risk ofbecoming chronically disabled by pain arecharacterised by past histories of mooddisorder and/or substance abuse, low self-efficacy and a perception of poor health,job dissatisfaction and/or manual labouroccupation, high pain intensity andcurrent perceived life stressors (Lintonand Hallden, 1998; Turk, 1997).

Studies by Croft et al (1998) and Vanden Hoogen et al (1998) have reportedthat the majority of patients with acuteback pain continue to experience pain at12 months follow-up. In the latter study,only 20% of the sample were fullyrecovered one year later. This researchsuggests the importance of early inter-vention in the pain cycle, to prevent thedevelopment of chronic disability and the host of accompanying psychosocialproblems such as work loss, medicationoveruse and depression. Although severalstudies have demonstrated the value ofpain management for acute back pain(Cooper et al, 1996; Linton et al, 1993), nostudy has evaluated such an interventionwithin a primary or secondary caresetting. Given that these are the settingsin which the majority of back painpatients are treated, they were consideredto be an appropriate research model.

Study Design and MethodsA community-based outpatient physio-therapy department was selected as thecentre in which to conduct the study (seelater section on Location). The studydesign was a cross-sectional, randomisedcontrolled trial. All new patients referredwith acute back pain would be screenedfor their ‘at-risk’ status, using the guide-lines suggested by Linton and Hallden(1998). Those found to be suitable for thestudy were to be allocated to one of twogroups using a random number table: aphysiotherapy as usual group (the control

Early Intervention in AcuteBack Pain Problems with Flying the Yellow Flag

Summary Disability related to chronic back pain has beenidentified as one of the major medical and social problems of current times. There is substantial evidence that painmanagement programmes based on cognitive behaviouralprinciples are effective in terms of improving physicalfunction and psychological well-being for long-term backpain sufferers (Morley et al, 1999). However, few studieshave investigated the efficacy of pain management withpatients in the early phases of the condition, before many of the problems associated with chronic pain havedeveloped. A project was therefore designed in order todetermine whether the provision of a pain managementintervention during the acute phase of back pain would help prevent the development of chronic disability.

For a variety of reasons this study did not proceed, and the aim of this article is to outline the pitfalls that wereencountered in setting up such a study. It is hoped thatfuture clinicians/researchers might benefit from our hindsight.

Key WordsBack pain, study design, Yellow Flags.

by Toby Newton-JohnJacqueline AshmoreMary McDowell

Newton-John, T,Ashmore, J andMcDowell, M (2001).‘Early intervention inacute back pain:Problems with flyingthe Yellow Flag’,Physiotherapy, 87, 8,397-401.

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condition) or a physiotherapy plus painmanagement group (the treatmentcondition).

The treatment group was to receive five one-hour sessions of a standardisedpain management intervention deliveredby the principal investigator, a clinicalpsychologist with experience in painmanagement (TN-J). The treatmentcomponents were based on widely usedcognitive behavioural pain managementstrategies (Williams and Erskine, 1995)and included education about pain andpain mechanisms, relaxation training,attention diversion exercises andcognitive therapy exercises. As it was notconsidered feasible for physiotherapists tofollow a manualised treatment protocol inthe same way, a maximum of ten treat-ment sessions was stipulated. The numberof physiotherapy sessions attended byeach subject was to be recorded, and usedas either a covariate or analysed separatelyfor any influence on outcome.

Three physiotherapists were involved intreating subjects recruited to the study.They were given two general seminars on psychological approaches to painmanagement, and then two specificseminars on biopsychosocial assessment inthe context of identifying Yellow Flags.This training particularly targeted the useand interpretation of the screeningmeasure developed by Linton andHallden (1998). As is often the case innaturalistic treatment trials, it was notpossible to blind the physiotherapists tothe subjects’ condition (treatment versuscontrol). The physiotherapists wereinstructed to carry out the treatment thatthey would normally prescribe for eachsubject, irrespective of treatment group,for no more than ten sessions.

Outcome was to be assessed in variousdomains. Pain intensity (numerical ratingscale), level of function (Roland-MorrisDisability Questionnaire, short form),mood (Hospital Anxiety and DepressionScale), and pain beliefs (Pain Catas-trophising Scale) were to be assessedusing standardised questionnaires.Medication use, number of days sick leave and healthcare usage (GP visits,emergency consultations, other painconsultations) were also importantoutcome measures. As these are all self-report measures, an objective method ofassessment was included: the five-minutetimed walk test (Harding et al, 1994).

Problems with Subject Recruitment Subjects were due to be recruited over an18-month period, in order to provide asufficient sample size for the requiredanalyses (see section on ProjectedRecruitment Figures). However, thenecessary subjects were not forthcoming.During the initial six-month subjectrecruitment period from June 1, 1999, to November 30, 1999, only five out of 63 potential subjects were found to be suitable for inclusion in the study. A decision was therefore made todiscontinue the trial.

Three main areas of the study designwere implicated in the subjectrecruitment problems: the inclusion/exclusion criteria, the location of thestudy, and the information upon whichthe projected recruitment figures werecalculated. These will be discussed inturn, along with suggested means ofovercoming the identified problems.

Inclusion/exclusion CriteriaDecisions regarding which kinds ofpatients to accept as subjects for the studywere based on existing research data. Theinclusion criteria were as follows: � First episode of back pain.� Onset of pain no longer than six weeks

previously.� Aged between 18 and 50 years.� Reasonable command of written and

spoken English.� No current psychotic illness or

substance abuse.� No surgical or other invasive medical

treatments being considered.

With regard to the first requirement,Linton et al (1993) showed that an earlyactivation programme was effective inreducing disability, improving mood,lessening pain intensity and reducing sickleave in acute back pain patients with noprior history of pain. However, patientswho had previously experienced backpain did not demonstrate any imp-rovement as a result of the intervention.Those patients, although not necessarilyin continuous pain, were deemed to havealready begun the descent into illnessbehaviour and catastrophic health beliefswhich compromised the efficacy of theirtreatment.

The time frame of six weeks after painonset was based upon the evidence of a

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study by Klenerman et al (1995) of 300acute low back pain patients presenting totheir general practitioners. These authorsfollowed the patient group over a 12-month period, and found that the level offunction reported at two months afteronset (assessed by self-reported disability,number of days sick leave and painintensity) could accurately predict funct-ioning 12 months later; 49% of the totalvariance in disability reported at 12months was predicted by scores obtainedat two months after onset (multiple R = 0.69, p < 0.0001). Hence, patients whoare not reporting significant recoveryeight weeks after onset are likely to becontinuing to experience difficulties oneyear later, which casts doubt upon thewidely adopted criterion of six months ofpersistent pain as the demarcation pointbetween acute and chronic pain. Sixweeks after onset was therefore employedas the time frame, in order to capturesubjects before they had already enteredthe ‘sub-chronic’ phase identified in thestudy above.

The age range for inclusion in the studywas set with a relatively low upper limit, tomaximise the probability of detecting atreatment effect on return to work data.While demonstrating that improvementon self-report measures of pain intensity,mood, disability and pain beliefs isimportant, it was felt that objective indicesof sickness absenteeism and return towork rates provided a more stringent testof treatment efficacy. However, as there isevidence that older workers do notbenefit as much from early interventionprogrammes as younger workers (Cooperet al, 1996), an upper age limit of 50 yearswas instituted. This age range is alsoconsistent with other early interventionstudies (eg Lindstrom et al, 1992; Lintonet al, 1993), in which the mean ages of thetreated subjects are 39.4 years (SD = 10.7)and 38.7-42.0 years (SD not reported)respectively.

Pain management interventions requirethe subjects to be actively involved intreatment, and this includes completingself-monitoring forms, filling in writtenhome-based assignments, and readingexplanatory materials (Williams andErskine, 1995). A reasonable level ofEnglish language skill is thereforenecessary, as is the cognitive ability toconcentrate and follow through oninstruction.

ProblemsFirst, it became clear that few patientspresenting to the physiotherapy servicewere first episode sufferers of acute backpain. The vast majority could be moreaccurately described as chronic, episodicback pain sufferers who were suffering aflare-up – hence their referral for physio-therapy. While the mainstream painliterature draws a clear distinctionbetween acute and chronic pain fornosological and research purposes, mostpublished pain research is conducted intertiary referral settings, such as specialistpain clinics or university research units.The clinical evidence at primary/secondary care level suggests a lesspolarised distinction between the twocategories. These data suggest a separate‘acute-on-chronic’ pain category, wherepatients experience recurrent painproblems interspersed with pain-freeperiods. This categorisation is also moreconsistent with the previously reportedfindings of Croft et al (1998) and Van denHoogen et al (1998).

Secondly, by the time most patients werereferred to the physiotherapy depart-ment and were given an appointment,they were well beyond the six weeks after pain onset criterion. As such, thosewith continuing pain complaints mayalready be in the sub-chronic category.Difficulties with spoken and writtenEnglish were also met, and severalpotential subjects fell outside the agerange.

As it became apparent that recruitmentwas problematic, an attempt was made toexpand the inclusion criteria in order toincrease the potential subject pool. Thus,rather than excluding all subjects with apast history of pain, the initial inclusioncriteria used by Linton et al (1993) wereadopted, so that subjects with a previouspain history, but no sick leave due to painfor the past two years, were included. Thetime limit for pain onset was extended toeight weeks, and the age range extendedupwards to 55 years. For those withEnglish language skill deficits, the use of afamily member as an interpreter wasaccepted. Despite these adjustments to theinclusion criteria, there was little differ-ence in the subsequent recruitment rate.

LocationIt was decided to locate the study in theoutpatient department of a community

Authors

Toby Newton-JohnPhD MPsychol is aconsultant clinicalpsychologist,University CollegeLondon Hospitals.

Jacqueline AshmoreMCSP is asuperintendentphysiotherapist at StMary’s Hospital,London.

Mary McDowell RN isa research nurse inthe Taylor Practice,London.

This article wasreceived on June 27,2000, and acceptedon February 22, 2001.

Address forCorrespondence

Dr Toby Newton-John,Consultant ClinicalPsychologist,Department of PainManagement,National Hospital forNeurology andNeurosurgery, QueenSquare, LondonWC1N 3BG.

Acknowledgements

This study was fundedby a grant from theNorth CentralThames Primary CareNetwork. The authorswould also like tothank thephysiotherapydepartment atTollington WayPhysiotherapy Centre,London N19 for theirsupport.

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physiotherapy service for three mainreasons. First, it is here that many of the at-risk back pain patients – thosepresenting with the psychosocial factorsknown to predict the development ofchronicity (Turk, 1997) – are referred for treatment. Recruitment to the studywould be facilitated by the patientsalready receiving treatment on site, ratherthan having to travel to a second locationin order to participate.

Secondly, close liaison was possiblebetween the clinician carrying out thepain management interventions (TN-J)and the physiotherapist to whom thepatient had been referred. This is espec-ially important when treatments areindividually tailored and delivered on anindividual basis (Kendall and Watson,1999).

Finally, the Yellow Flag model and therelevance of biopsychosocial assessmentappear to have been endorsed byphysiotherapists working with painpatients (eg Gifford, 2000), which rendersa physiotherapy department an approp-riate environment to carry out such astudy.

Problems The identified problem with the locationof the study was the time lag from painonset to the subject attending thephysiotherapy department. This delay wasnot due to waiting lists within thephysiotherapy department for initialappointments, as care had been taken toensure that patients would be screenedwithin one week of the referral beingreceived. The more likely explanation wasthat many GPs do not make an immediatereferral to physiotherapy when faced withan ‘acute’ back pain patient. Instead, theywait for several weeks for the pain to settle– and only refer if it has not subsided after this time. By locating the study at the end point of this referral process, theopportunity to pick up subjects earlier in the pain phase was missed.

Projected Recruitment FiguresBefore starting the study, the physio-therapy department’s audit figures for the previous 12 months were consulted.The aim was to ensure that a sufficientnumber of acute pain referrals were beingseen in the service to meet the studysample requirements. Power analysesrevealed that, assuming a moderate effect

size and one-tailed hypotheses, approx-imately 50 subjects per group wererequired in order to achieve power of0.80 (Cohen, 1988). Inspection of thedepartment audit revealed that a mean of4.5 new acute back pain referrals werereceived each week, indicating a sufficientnumber of referrals to meet the samplesize required.

ProblemsThe audit figures were based on inform-ation from the patient referral letters, noton the physiotherapists’ treatment notes.Hence, although patients’ referral lettersstated that the presenting complaint wasan acute back pain problem, interviewswith the patients invariably yieldeddifferent information. It became apparentthat, in most cases, these patients were the episodic-chronic pain sufferersreferred to previously, who were currentlyexperiencing a ‘flare-up’ of a long-heldproblem. This is the patient group whichthe data of Linton et al (1993) indicate is less responsive to early interventionprogrammes. Thus the audit figures hadgiven a misleading picture of how manypotentially suitable patients were beingseen in the service.

ConclusionDespite the fact that this study did notproceed, we believe that there are usefullessons for other clinicians consideringestablishing an early intervention service,or carrying out a research project basedon an existing clinical service. While firstepisode acute back pain patients mustexist (everyone has to start somewhere!) it appears that they are not commonlyseen in outpatient physiotherapy services.

A general practice would be the moreappropriate setting to establish this kindof study, where such patients can bepicked up at the first point of contact witha health professional. Information aboutearly intervention for acute back pain andready access to an early interventionprogramme may provide an incentivefor GPs to refer rather than to delayreferring.

Given previous research findings, we feltthat by relaxing our inclusion/exclusioncriteria any further, we would not becarrying out a fair and reasonable test ofthe efficacy of the early interventionmodel. While there is ample evidence ofthe benefits of cognitive behavioural pain

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management for chronic pain sufferers(Morley et al, 1999), the aims andobjectives of pain management for acute sufferers are quite different. Earlyintervention is targeting the prevention of disability and a return to normalfunctioning, rather than the chronic painmanagement objective of disabilityreduction. We maintained that as thisresearch has not yet been fully tested in anon-tertiary referral setting, the criteriashould not be altered any further.

However, evaluating pain management

in the context of chronic-episodic backpain is an equally valid research question.Pain patients who experience extendedpain-free intervals may require a differentkind of intervention from that typicallyprovided for daily pain sufferers,particularly addressing issues of relapseand dealing with setbacks. Given theexperience of this study it seems that, if nothing else, the recurrent painpopulation is a more pragmatic choice ofpatient group upon which to conductresearch.

References

Clinical Standards Advisory Group (1994).Back Pain: Report of a CSAG committee on backpain, HMSO.

Cohen, J (1988). Statistical Power Analysis for theBehavioral Sciences, Erlbaum, Hillsdale, NJ.

Cooper, J E, Tate, R B, Yassi, A and Khokhar, J(1996). ‘Effect of an early interventionprogramme on the relationship betweensubjective pain and disability measures innurses with low back injury’, Spine, 21, 2329-36.

Croft. P R, Macfarlane, G J, Papageorgiou, A C, Thomas, E and Silman, A J(1998). ‘Outcome of low back pain in generalpractice: A prospective study’, British MedicalJournal, 316, 1356-59.

Gifford, L (ed) (2000). Topical Issues in Pain 2,CNS Press, Falmouth.

Harding, V R, Williams, A C de C, Richardson, P H, Nicholas, M K, Jackson, J L,Richardson, I H and Pither, C E (1994). ‘The development of a battery of measures for assessing physical functioning of chronicpain patients’, Pain, 58, 367-375.

Klenerman, L, Slade, P, Stanley, I M, Pennie,B, Reilly, J P, Atchison, L E, Troup, J and Rose, M (1995). ‘The prediction of chronicityin patients with an acute attack of low backpain in a general practice setting’, Spine, 20, 478-484.

Lindstrom, I, Ohlund, C, Eek, C, Wallin, L,Peterson, L-E, Fordyce, W and Nachemson, A L (1992). ‘The effect of gradedactivity on patients with subacute low backpain: A randomised prospective clinical studywith an operant-conditioning behaviouralapproach’, Physical Therapy, 72, 279-293.

Linton, S J and Hallden, K (1998). ‘Can wescreen for problematic back pain? A screeningquestionnaire for predicting outcome in acuteand sub-acute back pain’, Clinical Journal ofPain, 14, 200-215.

Linton, S J, Hellsing A-L and Andersson, D(1993). ‘A controlled study of the effects of anearly intervention on acute musculoskeletalpain problems’, Pain, 54, 353-359.

Maniadakis, N and Gray, A (2000). ‘Theeconomic burden of back pain in the UK’,Pain, 84, 95-103.

Morley, S, Eccleston, C and Williams, A C DeC (1999). ‘Systematic review and meta-analysisof randomised controlled trials of cognitivebehaviour therapy and behaviour therapy forchronic pain in adults, excluding headache’,Pain, 80, 1-13.

Turk, D C (1997). ‘The role of demographicand psychosocial factors in transition fromacute to chronic pain’ in: Jensen, T S, Turner, J A and Wiesenfeld-Hallin, Z (eds)Proceedings of the Eighth World Congress on Pain,IASP Press, Seattle.

Van den Hoogen, H J, Koes, B W, van Eijk, J T M, Bouter, L M and Deville, W(1998). ‘On the course of low back pain ingeneral practice: A one-year follow-up study’,Annals of Rheumatic Disease, 57, 13-19.

Watson, P and Kendall, N (1999). ‘Assessingpsychosocial Yellow Flags’ in: Gifford, L (ed)op cit.

Williams, A C de C and Erskine, A (1995).‘Chronic pain’ in: Broome, A and Llewelyn, S(eds) Health Psychology: Processes andapplications, Chapman and Hall, London.

Key Messages

� Ensure co-operation of otherstaff involved in aproject – there isalways an element ofreliance on others forhelp, especially fromreceptionist/clericalstaff.

� Research projectsalways generate morequestions thanpossible answers. As all questions can’tbe answered by onestudy, decide on whatare the most salientissues and focus uponthem.

� Don’t takeanything for granted!Having determinedhow many subjectsare required, obtainfirst-hand evidence of their suitability,availability andwillingness toparticipate.

� Piloting variousstages of the project(time to completequestionnaires,acceptability oftreatment to patients,number of treatmentsessions required,etc) can help toshape the design ofthe study.

� Don’t be temptedto reduce yoursample size for thesake of expediency.The aim ofquantitative researchsuch as this is tomake generalisationsabout results, hencethe use of powercalculations. A studywithout enoughsubjects, no matterhow elegantlydesigned and wellexecuted, says verylittle about how otherindividuals mightbehave in the samecircumstances.