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Andrew Steptoe a Department of Psychology,
St George's Hospital Medical School, London SW17 0RE, b Department of General Practice and
Primary Care, St George's Hospital Medical School
Correspondence to: A Steptoe
asteptoe{at}sghms.ac.uk
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Abstract |
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Objective:
To measure the effect of behaviourally
oriented counselling in general practice on healthy behaviour and
biological risk factors in patients at increased risk of coronary heart disease.
Lifestyle change is central to health promotion and the prevention
of coronary heart disease.
1 2
Two large trials of coronary heart disease prevention, the family heart and OXCHECK studies,
3 4
have been particularly influential in British general practice. Although both showed small but significant effects on
risk of coronary heart disease, the results called into question the
cost effectiveness of health promotion in the general practice setting.5 Neither study concerned either patients at
increased risk of coronary heart disease or behaviourally oriented
counselling.
1 6
Lengthier programmes to alter smoking
habits, diet, and physical activity have more substantial
effects.7-9 Counselling directed at behavioural and
attitudinal change may produce greater changes than traditional
educational approaches to health promotion, particularly when tailored
to the individual's readiness to change.10-12 We describe the effects on behaviour and cardiovascular risk factors of
behaviourally oriented counselling on the basis of the stage of change
model.13 This model categorises patients into stages of
readiness to change behaviour (from precontemplation through contemplation, preparation, and action, to the maintenance of change),
with different types of advice and skill training being appropriate at
different stages. The intervention was carried out by practice nurses
in patients at increased risk of coronary heart disease. It was
hypothesised that compared with control, behavioural counselling would
lead to greater reductions in smoking and dietary fat intake and
increases in regular physical activity, together with greater
reductions in blood pressure, serum total cholesterol concentration,
weight, and body mass index.
The design of this parallel group randomised trial has been
described elsewhere.14 Twenty general practices were
allocated to intervention and control conditions (see website) using
the minimisation technique15 to balance groups for the
Jarman score of social deprivation,16 ratio of patient to
practice nurse hours per week, and fundholding status (including wave
of entry).
Patients were recruited on the basis of one or more modifiable
cardiovascular risk factors: regular cigarette smoking (more than one
cigarette per day), high serum cholesterol cocentration (6.5-9.0 mmol/l), or combined high body mass index (25-35) and low physical
activity (fewer than 12 episodes of vigorous or moderate exercise for
at least 20 minutes in the past 4 weeks, according to criteria based on
the national fitness survey).17 Patients were excluded if
they were on active follow up or drugs for coronary heart disease,
had had cardiovascular disease or peripheral vascular disease, had a
serious chronic illness, or were prescribed a special diet or lipid
lowering drugs.
The target sample size was 100 patients per practice. Taking
intracluster correlations of risk factors into account, we calculated that this would detect a drop in smoking prevalence from 50% to 41%,
and a decrease of 0.27 mmol/l in total serum cholesterol concentration
with 90% power at the 5% significance level.
After recruitment and baseline assessment patients were counselled by
practice nurses in smoking cessation, dietary fat reduction, and
increasing physical exercise as appropriate either using behaviourally oriented methods (intervention group) or their own usual methods, involving information provision and exhortation. Patients were reassessed at 4 and 12 months.
Behavioural counselling
Design:
Cluster randomised controlled trial.
Participants:
883 men and women selected for the
presence of one or more modifiable risk factors: regular cigarette
smoking, high serum cholesterol concentration (6.5-9.0 mmol/l), and
high body mass index (25-35) combined with low physical activity.
Intervention:
Brief behavioural counselling, on the
basis of the stage of change model, carried out by practice nurses to reduce smoking and dietary fat intake and to increase regular physical activity.
Main outcome measures:
Questionnaire measures of diet,
exercise, and smoking habits, and blood pressure, serum total
cholesterol concentration, weight, body mass index, and smoking
cessation (with biochemical validation) at 4 and 12 months.
Results:
Favourable differences were recorded in the intervention group for dietary fat intake, regular exercise, and cigarettes smoked per day at 4 and 12 months. Systolic blood pressure was reduced to a greater extent in the intervention group at 4 but not
at 12 months. No differences were found between groups in changes in
total serum cholesterol concentration, weight, body mass index,
diastolic pressure, or smoking cessation.
Conclusions:
Brief behavioural counselling by practice nurses led to improvements in healthy behaviour. More extended counselling to help patients sustain and build on behaviour changes may
be required before differences in biological risk factors emerge.
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Introduction
Top
Abstract
Introduction
Participants and methods
Results
Discussion
References
![]()
Participants and methods
Top
Abstract
Introduction
Participants and methods
Results
Discussion
References
One practice nurse from each of the 10 intervention practices was
trained in behavioural counselling on the basis of the stage of change
model. Training was adapted from the Health Education Authority's
package Helping People Change.
18 19
Nurses were trained both to assess a patient's readiness to change behaviour and to use attitude change, goal setting, and specific behavioural advice to enable change. Training took place over 3 days, with a
retraining and refresher day after 6 months. The goal in the smoking
intervention was complete abstinence, and counselling was supported by
nicotine replacement therapy when appropriate.20 Patients
with increased serum cholesterol concentration were counselled to
reduce dietary fat intake and to increase fruit and vegetable consumption within the context of a balanced diet, without specifying targets of the proportion of energy derived from fats. Patients with
combined increased body mass index and lack of regular physical activity were counselled to increase their activity levels to 12 sessions of moderate or vigorous activity per month.
Assessment measures
The physical assessment measures were calculation of body weight
and body mass index, and total serum cholesterol concentration and
blood pressure. Cholesterol was measured in all patients at 12 months,
but at 4 months only in those with initially increased concentrations.
Smoking status was assessed with validated questions,21
and patients who stopped smoking during the study and were not
currently using nicotine replacement therapy were asked to provide a
saliva sample for measurement of cotinine. The smoking outcome measures
were abstinence as verified by measurement of cotinine at 4 and 12 months together with reported number of cigarettes smoked per day.
Dietary fat intake was assessed with the dietary instrument for
nutritional education.22 Physical activity was measured as
the number of episodes of vigorous or moderate activity (as defined in
the national fitness survey assessment instrument) completed in the
past 4 weeks. Stage of change for smoking cessation, dietary fat
reduction, and increasing physical activity were assessed with measures
described elsewhere.23
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Results |
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Characteristics of the sample
A total of 316 intervention and 567 control patients were
recruited. The patients assigned to the two groups did not differ in
age (mean 46.7 (SE 0.4) years), sex distribution (406 men, 477 women),
and marital, educational, or employment status.14 At
baseline 404 participants were smokers (45.8% of the sample), 365 of
871 (41.9%) had cholesterol concentrations in the range 6.5-9.0 mmol/l, and 699 (79.2% of the sample) had a body mass index in the
range 25-35 coupled with insufficient regular physical activity. The
proportions of patients with one, two, and three target risk factors
were 43%, 48%, and 9% respectively.
Drop out from the study
Overall, 626 (70.9%) of the 883 patients entering the trial
completed the 4 month assessment, and 520 (58.9%) were assessed at 12 months (table 1). Failure to complete the trial was not related to sex,
education, occupation, or family history of cardiovascular disease.
Patients lost to follow up were younger than those who completed the
study. They were also more likely to be smokers and less likely to have
entered the study on the basis of cholesterol concentration or body
mass index and exercise criteria. Participants who smoked and those
with a serum cholesterol concentration <6.5 mmol/l tended to drop out
more in the intervention than control groups at 4 and 12 months. Of the
316 patients in the intervention group, 298 (90.2%) attended at least
one counselling session, 230 (72.8%) attended two, and 176 (55.7%)
attended three.
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Changes in behaviour and risk factors
Table 2 summarises the changes in risk behaviour and biological
risk factors at 4 months. Greater reductions in dietary fat and the
reported number of cigarettes smoked per day, and increases in physical
activity, were recorded in the intervention than control groups.
However, behaviour changes were not translated into differences in
biological risk factors. The only difference was in systolic blood
pressure, where the decrease at 4 months was greater in the
intervention than control groups. The smoking quit rate was 7.4% (95%
confidence interval
0.6 to 20.1) greater in the intervention than
control groups.
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9.6 to 28.3) greater in
the intervention than control groups. There were no differences in
response related to age, sex, or number of risk factors. Data related
to motivational stage of change will be described
elsewhere.
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Discussion |
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Behavioural counselling by practice nurses for lowering fat intake and increasing physical activity led to changes in target behaviours after 4 months, which were sustained at 12 months. Our study was successful in its primary aim of showing that brief counselling on the basis of the systematic application of behavioural principles is more efficacious in stimulating lifestyle modification than is the conventional counselling and advice provided in general practice. The results for smoking were equivocal, with differences in the number of cigarettes smoked per day but not in smoking quit rates. The smoking results were compromised by the differential drop out of smokers from the intervention group.
Problems of recruitment
We experienced considerable difficulties in recruitment and
retention to this study, and the dropout rate was higher than that
found in previous trials in general practice.
3 4
Young
smokers were especially likely to default, a pattern reported in other
studies of risk factor reduction.25 The decline in enthusiasm for primary prevention of coronary heart disease in general
practice over recent years may have contributed to this pattern. We
hoped to recruit similar numbers in the two arms of the trial, but the
control practices recruited nearly twice as many patients. The slower
recruitment in the intervention than control groups may have related to
the additional investment of time in carrying out behavioural
counselling. Additional research staff joined the study to work on site
to increase recruitment, and did succeed in increasing rates. Health
promotion checks had been carried out in several practices in previous
years and these had highlighted cardiac risks. Fewer patients than
anticipated were therefore available for assessment. The greater
dropout rate for the intervention group may have resulted from its more
demanding nature. Recruitment and retention required the commitment of
all staff and not only the study nurses, but many health professionals in primary care are ambivalent about advising patients in lifestyle change.26
Behaviour and risk factor changes
The changes in behaviour did not lead to differential reductions
in biological risk factors. A similar pattern has been observed in
other studies of lifestyle change.
27 28
One possible explanation is that patients showed a reporting bias in recalling the
number of cigarettes smoked per day, dietary fat consumption, and
physical activity. Although such a bias may have been operative, associations were recorded between changes in behaviour and changes in
related biological factors. In addition, biochemical verification of
smoking status identified only two cases in which self reported smoking
cessation was misreported.
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What is already known on this topic
Health promotion advice and lifestyle counselling in primary care have not produced substantial changes in cardiovascular risk factors Behavioural counselling for patients at increased risk of coronary heart disease may have greater effects What this study addsBrief behavioural counselling on the basis of the stage of change model led to greater changes in dietary fat intake, regular physical activity, and number of cigarettes smoked than with standard care More extended counselling and support may be needed to translate sustained changes in health behaviour into improvements in biological risk profil |
Implications for prevention of coronary heart disease
The primary aim of our study was to evaluate the impact of
behavioural counselling by practice nurses on high risk behaviours in
patients at increased risk of coronary heart disease. The efficacy of
the method has been shown, but given the difficulties of recruitment to
this study, the attrition rates, and the low impact of behavioural
change on measurable biological risk factors, the implications for
service general practice are less clear. More extended counselling may
be required to translate behaviour change into measurable reductions in
risk. Nevertheless in view of the increasing emphasis on disease
prevention within health improvement programmes, and the need for all
primary care groups to contribute to these, there may be an important
role for this counselling approach to appropriately targeted individuals.
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Acknowledgments |
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The Health Education Authority's primary health care unit in Oxford assisted with modifying the Helping People Change package. Further advice was obtained from Professor Brian Oldenburg (Queensland University of Technology), and Professor Robert West (St George's Hospital Medical School) contributed to the training in smoking cessation.
Contributors: AS and SH devised the original research question and developed the protocol with SD, ER, and TK. SD was responsible for nurse training, quality assurance, and data collection. TK, ER, and SD recruited the general practices, and ER managed contact with participating practices. SK led the work on power calculations and advised on analyses. AS carried out the analyses and wrote the first draft of the paper. AS and SH will act as guarantors for the paper.
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Footnotes |
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Funding: NHS research and development programme in cardiovascular disease and stroke.
Competing interests: None declared.
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References |
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(Accepted 29 July 1999)
Simon Day Leo Pharmaceuticals, Princes
Risborough, HP27 9RR
simon.day{at}leo-pharma.com
Simple randomisation is the standard method for allocating
participants to treatment groups in clinical trials. In the long run it
balances all features of participants across groups. Important prognostic factors may be identified at the design stage, and stratified randomisation can help to balance these features. Ensuring a
similar proportion of fund holders in the intervention and control groups was, reasonably, considered as important by Steptoe et al, as
was balancing for the Jarman score and the ratio of patient to practice
nurse hours per week.
Stratified randomisation seems a sensible option and works well when there is just one stratification factor. For example, stratification by fundholding status is simple: there are three randomisation lists, one for non-fundholders and one each for the first wave and second wave. Each must have balanced numbers for each treatment. However, simultaneous stratification for several factors can lead to more randomisation lists than there are participants in the study. With many factors, minimisation is more practical.
Minimisation works towards minimising the total imbalance across all
factors, rather than any one factor. Assume the first 18 general
practices had been randomised and are distributed as in the table. The
next general practitioner has a low Jarman score, a high patient to
practice nurse ratio "hours per week," and is a non-fundholder. The
number of practices of this type in the intervention group is 12
that
is, 4+5+3
and in the control group is 10
that is, 3+4+3. Hence, to
minimise the imbalance (even if not to eliminate it) this 19th practice
would be allocated to the control group.
Minimisation is possible by hand but a computer program helps when
there are many factors or more then two treatment groups. Planning to
use minimisation is a good discipline for making trialists think about
prognostic factors before a study starts and helps ensure adherence to
the protocol as a trial progresses.
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Footnotes |
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website extra: The flow of participants through the trial appears on the BMJ's website www.bmj.com
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