PAPERS

Randomised comparison of chiropractic and hospital outpatientmanagement for low back pain: results from extended follow up
T W Meade, Sandra Dyer, Wendy Browne, A 0 Frank
Abstract

Objective-To compare the effectiveness overthree years of chiropractic and hospital outpatientmanagement for low back pain.
Design-Randomised allocation of patients tochiropractic or hospital outpatient management.
Setting-Chiropractic clinics and hospital
outpatient departments within reasonable travelling
distance of each other in I I centres.
Subjects-741 men and women aged 18-64 years
with low back pain in whom manipulation was notcontraindicated.
Outcome measures-Change in total 0swestry
questionnaire score and in score for pain and patientsatisfaction with allocated treatment.
Results-According to total 0swestry scores
improvement in all patients at three years was about
291/6 more in those treated by chiropractors than inthose treated by the hospitals. The beneficial effectof chiropractic on pain was particularly clear. Those
treated by chiropractors had more further treatments for back pain after the completion of trialtreatment. Among both those initially referred fromchiropractors and from hospitals more rated
chiropractic helpful at three years than hospitalmanagement.

Conclusions-At three years the results confirm
the findings ofan earlier report thatwhen chiropractic
or hospital therapists treat patients with low backpain as they would in day to day practice thosetreated by chiropractic derive more benefit and longterm satisfaction than those treated by hospitals.

Medical Research Council
Epidemiology and Medical
Care Unit, Wolfson
Institute ofPreventive

Medicine, Medical Collegeof St Bartholomew's
Hospital, London

ECIM 6BQ

T W Meade, director
Sandra Dyer, statistician
Wendy Browne, research
nurse

Northwick Park Hospital,
Harrow HAI 3UJ
A 0 Frank, consultant inrheumatology andrehabilitation

Correspondence to:Professor Meade.
BMY 1995;311:349-51

BMJ voLumE 311

Introduction
In 1990 we reported greater improvement in patientswith low back pain treated by chiropractic comparedwith those receiving hospital outpatient management.'
The trial was "pragmatic" in allowing the therapists totreat patients as they would in day to day practice. At
the time of our first report not all patients had been in
the trial for more than six months. This paper presents
the full results up to three years for all patients forwhom follow up information from Oswestry questionnaires' and for other outcomes was available foranalysis. We also present data on pain from thequestionnaire, which is by definition the main com-naire on back pain, which gives scores for I 0 sections-for example, intensity of pain and difficulty withlifting, walking, and travelling.' The result is expressedon a scale ranging from 0 (no pain or difficulties) to100 (highest score for pain and greatest difficultyon all items). For an individual item, such as pain,scores range from 0 to I 0. The main outcome measures
are the changes in Oswestry score from before treatment to each follow up. At one, two, and three years
patients were also asked about further treatment
since the completion of their trial treatment or since
the previous annual questionnaire. At the three year
follow up patients were asked whether they thought
their allocated trial treatment had helped their backpain.

In the random allocation of treatment minimisation'

was used within each centre to establish groups for theanalysis of results according to initial referral clinic,
length of current episode (more or less than 'a month),presence or absence of a history of back pain, and an
Oswestry score at entry of > 40 or -,-- 40%.
Results were analysed on an intention to treat basis(subject to the availability of data at follow up as well as
at entry for individual patients). Differences between
mean changes were tested by unpaired t tests, andX2 tests were used to test for differences in proportions
between the two treatment groups.

Results
Follow up Oswestry questionnaires were returnedby a consistently higher proportion of patients allocatedto chiropractic than to hospital treatment. At sixweeks, for example, they were returned by 95% and89% of chiropractic and hospital patients, respectively
and at three years by 77% and 70%.
Mean (SD) scores before treatment were 29-8 (14-2)
and 28-5 (14-1) in the chiropractic and hospitaltreatment groups, respectively. Table I shows thedifferences between the mean changes in total Oswestry
scores according to randomly allocated treatmentgroup. The difference at each follow up is the meanchange for the chiropractic group minus the meanchange for the hospital group. Positive differences

i-Differences (95% confidence intervals) between meanchanges in Oswestry scores*TABLE

plaint prompting referral or self referral.

Methods
Methods were fully described in our first report.'
Patients initially referred or presenting either to a
chiropractic clinic or in hospital were randomly
allocated to be treated either by chiropractic or inhospital. A total of 741 patients started treatment..
Progress -was measured with the Oswestry question5 AUGUST 1995

No of patients

Time offollow upSix weeks
Six months
One year
Two years
Three years

Difference
1-69 (-0-74 to 4-12)
3-3 If (0-51 to 6-1 1)
2.04 (- 0.71 to 4.79)

3-02t (0-08 to 5-96)
3-18t (0- 16 to 6-20)

No of patients

undergoingchiropractic

undergoinghospital treatment

357
325
314
285
290

309
282
265
256
239

*Positive differences indicate greater improvement in patients treated withchiropractic.
tP < 0-02; tP < 0-05.

349

therefore reflect more improvement (due to a greaterchange in score) in those treated by chiropractic thanin hospital (negative differences the reverse). The
3-18 percentage point difference at three years intable I represents a 29°/o greater improvement inpatients treated with chiropractic compared withhospital treatment, the absolute improvement in thetwo groups at this time being 14 1 and 10-9 percentage
points, respectively. As in the first report those withshort current episodes, a history of back pain, andinitially high Oswestry scores tended to derive mostbenefit from chiropractic. Those referred by chiropractors consistently derived more benefit fromchiropractic than those referred by hospitals.
Table II shows changes between the scores on pain
intensity before treatment and the correspondingscores at the various follow up intervals. All thesechanges were positive-that is, indicated improvement-but were all significantly greater in those treated bychiropractic, including the changes early on-that is,
at six weeks and six months, when the proportions
returning questionnaires were high. As with theresults based on the full Oswestry score the improvement due to chiropractic was greatest in those initiallyreferred by chiropractors, although there was alsoa non-significant improvement (ranging from 9%
at six months to 34% at three years) due to chiropractic at each follow up interval in those referred byhospitals.
Other scores for individual items on the Oswestry
index to show significant improvement attributable tochiropractic were ability to sit for more than a shorttime and sleeping (P=0'004 and 0 03, respectively, atthree years), though the differences were not as
consistent as for pain. Other scores (personal care,lifting, walking, standing, sex life, social life, andtravelling) also nearly all improved more in the patientstreated with chiropractic, though most of the differences were small compared with the differences forpain.
Higher proportions of patients allocated to chiropractic sought further treatment (of any kind) for backpain after completion of trial treatment than thosemanaged in hospital. For example, between one and
TABLE n-Changes in scores from section on pain intensity in Oswestry
questionnaire between score before treatment and score at follow upintervals according to method of treatment and difference betweenchangesInterval andmethod oftreatment

NoofpatientsMeanchangescore

Difference (SE)between changes

P value

0 28 (0 08)

0-00060301)
036 (010)

000
00002

0-21(0 10)

0 03

0 35 (0-11)

0-001

031(011)0004

in

Six weeks:

Chiropractic

357

0.99

Hospital

309

0.71

324

0°67

Six months:
Chiropractic

Hospital
One year:

282

1.03

Chiropractic

314

0°94

Hospital

265

0-73

Chiropractic

285

0.98

Hospital

2560

Two years:
63

Three years:

Chiropractic

290

0590

Hospital

239

0-59

031(1)TABLE III-Number (percentage)of patients at three year follow up
who considered allocated trial treatment had helped their back pain
Hospital treatment
ReferralHelp

No help

Help

No help

Hospital

71 (60 2)

47 (39 8)103 (79 2)

27 (20 8)

Chiropractic

76 (65 5)

40 (34 5)

127 (84 7)

23 (15-3)

For hospital referrals: x2= 10-7; P=0 001.
For chiropractic referrals: x2= 13-3; P < 0-0001.

350

Chiropractic treatment

Key messages* Back pain often remits spontaneously* Effective treatments for non-remitting
episodes need to be more clearly identified* Chiropractic seems to be more effective thanhospital management, possibly because moretreatments are spread over longer time periods* A growing number of NHS purchasers aremaking complementary treatments, including
chiropractic, available* Further trials to identify the effective
components of chiropractic are needed

122/292 (42%) patientstreated with chiropractic compared with 80/258 (3 1%)of hospital treated patients did so (Xl=6 8, P=0 0 1).
Table III shows the proportions of patients at threeyears who thought their allocated trial treatment had
helped their back pain. Among those initially referredby hospitals as well as among those initially referredby chiropractors higher proportions treated bychiropractic considered that treatment had helped
compared with those treated in hospital.
two years after trial entry

Discussion
The results at six weeks and six months shown intable I are identical with those in our first report,' as all
patients had then been followed up for six months. The
findings at one year are similar as many patients had
also been followed up then. The considerably larger
numbers of patients with data now available at two andthree years show smaller benefits at these intervals thanpreviously,' though these still significantly favour
chiropractic. The substantial benefit of chiropractic on
intensity of pain is evident early on and then persists.
The consistently larger proportions lost to follow up
throughout the trial in those treated in hospital thanin those treated by chiropractic suggests greater
satisfaction with chiropractic. This conclusion issupported (table III) by the higher proportions in eachreferral group considering chiropractic helpful bycomparison with hospital treatment.
The main criticism of the trial after our first report
centred on its "pragmatic" nature, particularly thelarger number of chiropractic than hospital treatments
and the longer period over which the chiropractic
treatments were spread and which were deliberately
allowed. These considerations and any consequencesof the higher proportions of patients allocated tochiropractic who received further treatment in the laterstages of follow up, however, do not apply to the results
at six weeks and only apply to a limited extent at six
months, when the proportions followed up were highand extra treatment had either not occurred at all or
was not yet extensive. Benefits atributable to chiropractic were already evident (especially on pain, tableII) at these shorter intervals.
We believe there is now more support for theneed for "fastidious" trials focusing on specific components of management and on their feasibility.
Meanwhile, the results of our trial show that chiropractic has a valuable part to play in the management oflow back pain.
We thank Dr Iain Chalmers for commenting on an earlier
draft of the paper. We thank the nurse coordinators, medicalstaff, physiotherapists, and chiropractors in the 11 centres fortheir work, and Dr Alan Breen of the British Chiropractic
Association for his help. The centres were in Harrow,BMJ

VOLUME 311

5 AUGUST 1995

Taunton, Plymouth, Bournemouth and Poole, Oswestry,
Chertsey, Liverpool, Chelmsford, Birmingham, Exeter, andLeeds. Without the assistance of many staff members in eachthe trial could not have been completed.
Funding: Medical Research Council, the National Back
Pain Association, the European Chiropractors Union, and theKing Edward's Hospital Fund for London.
Conflict of interest: None.

1 Meade TW, Dyer S, Browne W, Townsend J, Frank AO. Low back pain of
mechanical origin: randomised comparison of chiropractic and hospital
outpatient treatment. BMJ 1990;300:1431-7.
2 Fairbank J, Davies J, Coupar J, O'Brien JP. Oswestry low back pain disability
questionnaire. Physiotherapy 1980;66:271-3.
3 Simnon R. Sequential treatrnent assignment with balancing for prognostic factors
in the controlled clinical trial. Biometrics 1975;31:103-15.

(Accepted 12_June 1995)

Using decision analysis to compare policies for antenatal screeningfor Down's syndrome
J Fletcher, N R Hicks, J D S Kay, P A Boyd

Department ofPublic
Health and Health Policy,
Oxfordshire Health
Authority, Oxford

OX3 7LGJ Fletcher, senior registrar in
public health medicine

N R Hicks,
consultant public healthphysician
Department ofClinical
Biochemistry, Oxford
Radcliffe Hospital,
Oxford OX3 9DU
J D S Kay, consultant

chemical pathologist
Maternity Department,
Oxford Radcliffe Hospital,
Oxford OX3 9DU
P A Boyd, clinical coordinatorfor prenatal diagnosis
Correspondence to:
Dr Hicks.
BMJ 1995;311:351-6

BMJ VOLUME 311

gestational age of the fetus, allows a more accurate
estimation of the risk of a fetus being affected with
Down's syndrome than does risk estimation based on
matemal age alone.' 2 This has raised the possibility ofintroducing biochemical testing as a screening test for
Down's syndrome for some or all pregnant women.
However, there is no consensus among health authorities in Britain as to whether biochemical screeningfor Down's syndrome should be offered and if so towhich groups of pregnant women.3 The main issues
that have been the topics of professional and publicdebate are the ethics of prenatal screening; theperformance of biochemical screening tests; the choiceof test; the relative costs, both personal and monetary;whether centres which introduced biochemical screening early have done the right thing; and the importanceof counselling.47
The consequences of screening for Down'ssyndrome are various. They may include changes in
the number of Down's syndrome babies detected, thenumber of Down's syndrome babies born, the numberof unaffected babies born, the number of pregnancies
lost by miscarriage, the amount of anxiety generated,
and the direct and indirect financial costs of theprogramme to the NHS, other agencies, and pregnant
women and their families. Most published contributions to the debate have provided information about
only one or two measures of outcome such as detection
rate' or psychological costs.58 Others have used summary measures such as overall cost or saving per
Down's syndrome case detected.9 However, a decision
to implement a particular screening programme should
be based on as full an assessment of as many as possibleof the relevant outcomes of a screening programme. In
1993, in the absence of clear regional or national
guidance, Oxfordshire health authority had not
decided whether to purchase a serum screening programme. In that same year about a third of pregnant
women over 35 years in Oxfordshire chose to pay
around £50 each to have biochemical tests for Down's
syndrome performed privately; this choice was available only to those who could afford to pay. This waswidely regarded as unsatisfactory. A decision wasrequired about the NHS provision of serum screeningfor Down's syndrome for the women of Oxfordshire.
The district health authority sought a screening option
women.
that was as effective or better at detecting Down's
syndrome than current practice; addressed the conIntroduction
troversy surrounding stress and the screening ofMaternal serum concentrations of various analytes younger women; and was cost neutral or cheaper inincluding a fetoprotein, oestriol, and human chorionic direct NHS costs than current practice.
We wanted to use the large amount of national andgonadotrophin can be used to estimate the probability of a fetus having Down's syndrome. Wald and local data that is available about biochemical screening
colleagues have predicted and subsequently shown for Down's syndrome to quantify as many as possiblethat information derived from measurements of of the likely consequences of different screening
various combinations of such analytes, when inter- options for the population of Oxfordshire. We usedpreted in the knowledge of a woman's age and the the technique of decision analysis, which is a well
Abstract
Objective-To compare different screening
policies for Down's syndrome across a broad rangeof outcomes, using decision analysis, with particularreference to the role of maternal serum testing.
Design-A decision tree was used to combine datafrom local sources and the medical literature topredict the likely frequency of several outcomes.
Sensitivity analyses were used to test the robustness
ofthe conclusions drawn.
Setting-Oxfordshire Health Authority.
Main outcome measures-Live births with andwithout Down's syndrome; miscarriages withDown's syndrome; cases of Down's syndrome
detected antenatally; amniocenteses performed(and associated miscarriages); direct NHS screening costs; number of women offered screening.
Results-Screening policies for Down's syndromethat include serum testing can produce better population outcomes than programmes that do not.
Each option for screening for Down's syndrome that
we considered had significant drawbacks. In Oxfordshire, offering serum testing to women of all ages
would prevent the birth of approximately one more
baby with Down's syndrome per year than would apolicy of screening for women aged 30 years or more.
The cost of preventing this one extra Down's birthwould be one or two normal babies lost after
amniocentesis, 4500 blood tests for young women(with the associated anxiety and counselling),
approximately 200 false positive serum test results
and amniocenteses (with the associated anxiety anddistress), and £90000 for the extra tests, counselling,and amniocenteses. Opinions are divided as to which
policy is the better option for the population.
Conclusions-Decision analysis is a useful tool for
determining the likely consequences of different
policy options across a broad range of outcomes.
This focuses debate and decision making on outcomes of care, which in turn makes it clear thatthe choice of screening programme for Down's
syndrome depends on the relative importanceascribed to the different outcomes. If individuals'
values vary widely it may be impossible to find one
screening policy that meets the needs of all pregnant

5AUGUsT1995

351