BMJ No 7108 Volume 315
Papers Saturday 6 September 1997
A cost effective, community based heart health promotion project in England: prospective comparative study
Tony Baxter, Philip Milner, Keith Wilson, Mike Leaf, Jon Nicholl, Jenny Freeman, Nicola Cooper
Abstract
Objective: To determine whether a community based coronary heart disease health promotion project, undertaken over four years, was associated with changes in the prevalence in adults of lifestyle risk factors known to affect the development of coronary heart disease, and to estimate whether such an approach was cost effective.Design: Prospective, comparative study of the effects of a health promotion intervention on coronary heart disease lifestyle risk factors, assessed by postal questionnaire sent to a randomly chosen sample, both at baseline and after four years.
Subjects: Intervention and control populations of adults aged 18-64 in Rotherham, both from areas with a high incidence of coronary heart disease and similar socioeconomic composition.
Main outcome measures: Changes in prevalence of lifestyle risk factors between the control and intervention communities from 1991 to 1995. The effect of the intervention on certain lifestyle behaviours was evaluated using multiple logistic regression to model the proportion with a particular behaviour in the study communities as a function of age (18-40 or 41-64 years), sex, the year of observation (1991 or 1995), and area (intervention or control).
Results: 6.9% fewer people smoked and 8.7% more drank low fat milk in the intervention area, but no other statistically significant changes between the areas were detected. The estimated cost per life year gained was £31.
Conclusions: It is possible to have a cost effective impact on coronary heart disease lifestyle risk factors in a population of adults over four years using only modest resources.
Introduction
Once established, coronary heart disease is impossible to cure, so a successful prevention strategy is the only way to reduce the long term burden. Lifestyle risk factors are associated with the development of and mortality from coronary heart disease.(1-7) Prevention projects that focus on lifestyle risk factor modification have been shown to reduce the development of coronary heart disease and mortality from it.(8-11)
In 1991 we began a controlled, before and after study of the effects of a health promotion programme (Action Heart) using a population approach lasting four years to determine whether such an intervention was cost effective in a typical, non-teaching, English health district. The findings for children have been reported elsewhere.(12) We now report our findings in adults. Our objective was to evaluate the potential for producing lifestyle changes that affect the development of coronary heart disease.
Methods
The study design was a prospective, comparative study of the effects of the Action Heart health promotion intervention among two populations of adults. The intervention area, the adjacent communities of Swinton and Wath, was chosen for its high incidence of coronary heart disease. The control area (Maltby) had a similar record for coronary heart disease and socioeconomic composition (table 1). It was also sufficiently far from the intervention area to minimise contamination.
| Table 1 - Standardised mortality ratios (SMR) from coronary heart disease in 1981-8 (95% confidence intervals) and rankings and values of electoral wards for deprivation indicators for control (Maltby) and intervention (Swinton and Wath) areas in 1990 | |||
| Under 65 SMR1981-1988 | Maltby | Swinton | Wath |
|---|---|---|---|
| Men | 138 (129 to 147) | 131 (123 to 139) | 136 (128 to 144) |
| Women | 190 (184 to 196) | 176 (171 to 181) | 170 (165 to 175) |
| Deprivation rankings* (and values): | |||
| Jarman score | 14 (3.5) | 12 (1.5) | 9 (-1.2) |
| Department of the Environment index | 13 (0) | 11 (-0.6) | 8 (-1.0) |
| Rotherham Metropolitan Borough Council index | 16 (28) | 9 (12.0) | 13 (23.0) |
| Unemployment rate | 12 (11.8) | 10 (11.3) | 7 (10.4) |
| *Among the 22 electoral wards in Rotherham | |||
Action Heart used several recognised health promotion approaches(13) (see appendix 2).
| Appendix 2 Health promotion approaches and examples of interventions used in the Action Heart project |
||
| Health promotion approach | Definition | Examples of interventions |
| Behaviour change | Attitude and behaviour change to encourage adoption of healthier lifestyles | Stop smoking support groups; weight control clinics; healthier eating activities |
| Educational | Information about cause and effects of factors detrimental to health, exploration of values and attitudes, development of skills required for healthy living | My Body Project; Look After Yourself courses; information leaflets; library resources |
| Empowerment | Working with health issues, choices and actions which clients identify | Action Heart Club |
| Medical | Promotion of medical intervention to prevent or ameliorate health | Blood pressure screening; Action Heart body check ups; nicotine patch scheme |
| Social change | Political/social action to change physical/social environment | Institutional Action Heart Charters |
We assessed risk factor status using a self completed questionnaire covering personal details, sources of health information, personal history of blood pressure and cholesterol measurement, family health history, diet, exercise, and smoking. Questions were chosen on the basis that they had previously been used in postal questionnaires; were free from bias and ambiguity; were appropriate for the Action Heart survey; had content validity; and were the subject of previous research.(14,15) The questions relating to smoking and milk consumption are shown in Appendix .
| Appendix 1 Questions relating to smoking status and milk consumption used in the Action Heart survey | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
At the time of sample size determination we did not know whether our study would receive funding and whether we could do a follow up survey. However, we wanted to have good estimates of risk factor prevalence in the populations, while recognising that the sample size would be limited by the financial resources available. In undertaking sample size calculations based on confidence interval estimates, we assumed that (a) levels of risk factors in both areas were the same at baseline; (b) reductions in the level of cigarette smoking were the primary end point; (c) the prevalence of smoking in both areas was 34% at baseline; and (d) reductions over three years in the prevalence of cigarette smoking attributable to Action Heart which would be considered of public health importance were of the order of 2%.
To estimate smoking prevalence within 1% of the true value with 95% probability required an achieved sample size of 1509 from each area. To attain this, we mailed 1887 questionnaires to each area assuming an 80% response rate. We assumed that any background changes in smoking prevalence would be the same in both areas. The General Household Survey estimated that smoking prevalence was reducing by 1% per year in the age groups chosen.(16)
Questionnaires were mailed to a randomly chosen sample of named adults from the Rotherham Family Health Services Authority population age-sex register. The baseline survey was carried out in July 1991. The post-intervention survey was carried out in June 1995 using a similar approach but sent to a different random sample. (Following the cohort of individuals identified in the baseline survey would have increased statistical power but cost too much.)
The proportions of questionnaires mailed to the subgroups of men or women aged 18-40 or 41-64 were the same in both intervention and control areas for the 1991 survey. In the 1995 survey the proportions of mailed questionnaires were adjusted to try to achieve equal numbers of respondents in each of the four age-sex subgroups based on the 1991 survey response rates. This ensured best estimates of risk factor prevalences in the subgroups. However, the response proportions for age-sex subgroups were not the same as those in the underlying population for both areas as measured by the 1991 and 1995 estimates from the Office of Population Censuses and Surveys modified by local authority estimates. To adjust for overcoverage and undercoverage in the four age-sex subgroups due to this sampling frame error(17) we weighted the responses so that they were directly proportional to the corresponding subgroups in the OPCS ward populations. Weighted data were used only in the univariate analysis. Age and gender terms were used in all of the logistic regression models.
Coding - Decision rules for coding to define outcomes were made by the senior registrar in public health and a research officer.
Analysis - A univariate analysis was used to compare the prevalence of lifestyle risk factors between the control and intervention communities from 1991 to 1995. The effect of the intervention on lifestyle behaviours was evaluated using multiple logistic regression to model the proportion with a particular behaviour in the study communities as a function of age-group (18-40 or 41-64 years), sex, the year of observation (1991 or 1995), and area (intervention or control). After modelling the prevalence of the lifestyle behaviours for sex, area, and age group separately, the effect of the intervention was measured by comparing the change in the proportion showing that behaviour between 1991 (preintervention) and 1995 (post-intervention) in the intervention area with the change between 1991 and 1995 in the control area, the test being based on the interaction between year and area. We also examined whether the effect of the intervention differed between the age groups and sexes.
Economics - A cost-effectiveness analysis was undertaken from the perspective of the purchaser, Rotherham Health Authority, to determine the technical efficiency of the Action Heart programme compared with traditional investment in disease management and other health promotion approaches to coronary heart disease. Outcomes were measured in units of life years gained, estimated from reported changes in smoking status using an epidemiological model. Cost data were collected in two ways. Firstly, data were extracted from financial records kept during the trial which listed actual expenditure over the four year study from a designated budget. Secondly, estimates of non-project staff costs and overheads incurred by the project were measured using diaries and timesheets kept by staff since the launch of Action Heart. Whitley Council pay scale rates were used to estimate the value of staff time. Costs relating to the research aspects of the trial were excluded from this analysis. Costs were discounted at the government recommended rate of 6%.(18)
Results
Response rates of 82-86% were achieved for both baseline and post-intervention surveys (in 1995, when responses were analysed by subgroup, these ranged from 74% in men aged 18-40 in the control area to 93% in women aged 41-46 in the intervention area).
Univariate analysis
Smoking decreased in the intervention area between 1991 and 1995
but increased in the control area: the difference in smoking prevalence
between the two areas increased from 4.2% in 1991 to 9.2% in 1995.
The only other marked difference in risk factor prevalence between the
areas was for low fat milk consumption, which increased by 7.6% (table
2).
| Table 2 - Risk factor comparisons between Action Heart control and intervention areas for 1991 and 1995. Values are percentages (and numbers) | |||
| Risk factor and area | 1991 | 1995 | Estimated effect %* (95% CI) |
|---|---|---|---|
| Active smoking: | |||
| Intervention | 32.2 (495) | 28.8 (417) | -24.5 (-39.4 to -6.1) |
| Control | 36.4 (511) | 38.0 (578) | |
| Passive smoking: | |||
| Intervention | 41.8 (434) | 33.8 (344) | -7.6 (-28.8 to 19.8) |
| Control | 49.2 (450) | 42.4 (397) | |
| Wholemeal bread: | |||
| Intervention | 23.6 (368) | 25.0 (355) | 9.2 (-11.7 to 35.1) |
| Control | 17.2 (247) | 18.9 (283) | |
| Low fat spreads: | |||
| Intervention | 61.8 (963) | 66.0 (946) | -1.1 (-19.4 to 21.5) |
| Control | 58.0 (831) | 62.5 (937) | |
| Low fat milk: | |||
| Intervention | 48.2 (752) | 71.0 (1038) | 42.5 (14.8 to 77.0) |
| Control | 53.6 (767) | 68.8 (1055) | |
| Exercise: | |||
| Intervention | 53.7 (836) | 52.8 (781) | 2.7 (-17.2 to 27.3) |
| Control | 52.7 (754) | 50.6 (790) | |
| Obesity or overweight: | |||
| Intervention | 45.4 (689) | 51.4 (752) | 9.7 (-15.1 to 41.6) |
| Control | 50.5 (697) | 57.9 (887) | |
| Blood pressure: | |||
| Intervention | 81.8 (1268) | 86.4 (1274) | 28.8 (-4.6 to 73.9) |
| Control | 84.4 (1204) | 85.3 (1317) | |
| Cholesterol: | |||
| Intervention | 14.7 (228) | 29.6 (436) | -2.4 (-25.1 to 27.3) |
| Control | 13.1 (186) | 30.2 (467) | |
| *Estimated adjusted percentage change in the odds of the risk factor in the intervention group compared with the control group over the study period. | |||
Multiple logistic regression
The odds ratio for active smoking in the intervention area in 1995
compared with 1991 was 0.83 (95% confidence interval 0.71 to 0.97); in
the control area it was 1.1 (0.95 to 1.29). The difference in these
odds ratios is statistically significant (chi2=6.4,
P=0.01), providing statistical evidence of an effect for the
intervention over all age-sex groups. There was no evidence that the
intervention effect differed between the age groups
(chi2=0.33, P>0.5), but weak evidence that it differed for
men and women between 1995 and 1991(chi2=2.6, P=0.11),
which suggests a relative increase in smoking rates for women in the
control area but little difference for men.
The odds ratio for drinking low fat milk in 1995 compared to 1991 in the intervention area was 2.58 (2.22 to 3.01) and in the control area 1.81 (1.55 to 2.11; chi2=10.3, P<0.001). There was no evidence that the intervention effect differed between the age groups (chi2=0.11, P>0.5), but there was weak evidence that it differed between sexes (chi2=3.12, P<0.05). There was an approximate doubling in the odds of using low fat milk between 1991 and 1995 in men in both the intervention (odds ratio=2.30) and control (1.95) areas; the effect was slightly less for women in the control area (1.68), while for women in the intervention area the odds trebled (2.93).
There were no statistically significant odds ratio differences for the other risk factors. An alternative analysis was also done using the baseline values as a covariate in a covariance style regression model . The results were very similar to those presented above.
The costs of the Action Heart community project incurred by Rotherham Priority Health Trust are shown in table 3. Overall, 57% of the £108,774 spent went on Action Heart project staff, 35% on other NHS workers, and 8% on schools expenditure.
| Table 3 - Resource consumption in the community project | |||
| Resources used | Units used | Cost per unit (£ per hour) | Total cost (£) |
|---|---|---|---|
| Community project officer | 1 worker | 11.19 | 25,322 |
| Community project worker | 1 worker | 5.38 | 12,439 |
| Consumables | N/A | N/A | 22,653 |
| Other costs eg telephones | N/A | N/A | 1,300 |
| Total | 61,714 | ||
| Meetings | 889 hours | 10.86 | 9,654 |
| Events: | |||
| Preparing | 1,663 hours | 10.86 | 18,060 |
| Executing | 983 hours | 10.86 | 10,665 |
| Total | 38,379 | ||
| Schools expenditure | 8,681 | ||
| Grand total | 108,774 | ||
| N/A = unable to express in terms of cost per units. | |||
Discussion
The primary aim of Action Heart was to produce lifestyle changes that would influence the development of coronary heart disease using a community based prevention approach. The results show that over four years there have been important reductions in smoking - our primary end point - in the intervention area and also significant increases in consumption of lower fat milk. The quasi-experimental study design we used to evaluate Action Heart(19) enabled us to control for confounding factors as far as possible.
Routine data provided no evidence on socioeconomic factors in these areas that could account for the observed lifestyle changes. For example, unemployment rates were similar in both areas in 1991 and 1995, and both areas had experienced similar declines, from 11.1% to 9.6% in the intervention area and from 11.4% to 10.2% in the control area. We have not been able to identify any other factors that might account for such lifestyle changes. The most likely explanation is that they were associated with the intervention.
A computer model based on the American Cancer Society's 50 state study on cancer prevention(20) predicts that the median gain in life expectancy for the age group 18-64 years will be 3.5 years (R Anderson, Department of Health). Of the 14 500 people in the intervention area, we estimate that 6.9% (1.3 to 12.25) more of them would be active smokers had Action Heart not taken place, resulting in an estimated health gain of 3581 life years in the intervention area. The gain may actually be greater since it would probably have accrued to the elderly as well.
The cost of the project was about £110 000. The greatest area of
uncertainty in this figure relates to other NHS costs, which
contributed about £40 000 (table 3). If we have underestimated these
costs by 100% Action Heart would have cost £150 000. This potential
underestimate was used as the basis for a sensitivity analysis. If the
project cost was accurate the undiscounted cost per life year gained
associated with Action Heart was £31; if the cost was in fact
£150 000, the undiscounted cost would increase to £42. With a
discount rate of 6% the costs would be £117 and £160 respectively.
In either case, Action Heart represents good value when compared with
other healthcare interventions for a variety of
diseases,(21) health checks such as the Oxcheck and British
family heart studies,(22-24) primary and secondary
coronary heart d We measured the benefits from quitting smoking in natural units
of life years gained which would be realised at the end of an
individual's life. Discounting the benefits gives more weight to the
life years gained by elderly people who stop smoking because they reap
the benefits sooner. We have not measured the other health benefits to
be gained from quitting smoking which would be realised at an early
age. We also have not estimated the health service costs avoided by the
likely reduction in episodes of treatment for smoking related diseases.
We have therefore probably underestimated the health and resource
benefits likely to accrue from Action Heart.
A longer follow up is required to assess fully the long term
effectiveness and overall cost effectiveness of Action Heart. We cannot
identify which aspects of the project contributed to the change in
smoking prevalence or why most other risk factors showed no significant
changes in prevalence. We also note an alarming increase in the
prevalence of overweight and obese adults in both intervention and
control areas.
We believe that the change in low fat milk consumption between control
and intervention areas could be attributed largely to a "Wake up to
semiskimmed milk" promotion which took place in spring 1994 and
summer 1995, financed by Action Heart and two local dairies. Leaflets
promoting low fat milk were delivered to 7,000 households in 1994 and
4,000 in 1995. The difference was relatively small compared with the
background trend (table 3). We estimated that if half the population
who drank full milk changed to semiskimmed milk, and had energy and fat
daily intakes of 2300 kcal and 100 g, they would lose about 5 g of fat
from their daily diet. Since half of the population is drinking low fat
milk already, this would reduce the percentage energy from fat on
average from 40% to 39%. But we know this percentage is reducing only
slightly because of fat substitution.(28) The exact impact
on the Health of the Nation target for the percentage energy from fat
is therefore difficult to quantify.
Evidence from heart attack registers suggests that much of the
fall in mortality from coronary heart disease in most developed
countries is due to changes in risk factors rather than to advances in
medical care.(29,30) Some form of heart health promotion
programme is taking place in every health district in England and in
similar populations in many other countries worldwide. The resources
allocated to each of these programmes are unlikely to have reached even
the modest allocation to Action Heart, and few are likely to have been
adequately evaluated. We believe that there are international
implications from our study for investment policy in local heart health
promotion programmes given the overall paucity of investment in this
area.
We thank all involved in the Action Heart Project, in
particular Gina Higginbottom, Action Heart Project Officer; Steve
Hawkins, Director of Health Promotion; Caroline Simpson, Senior Health
Promotion Officer; Trisha Owen, Primary Care Clinical Manager; John
Brazier, Director of Health Economics at the Sheffield School of Health
and Related Research; Alison Evans, Community Dietitian; Gayle Quick,
Action Heart Health Visitor; Carole Pearson, Action Heart Project
Worker; Joanne Coy, Research Officer; Marcus Williamson, Research
Officer; and Liz Galliver, Local Education Authority Officer. We also
thank Robert Anderson and Barrie Margetts for their help.
Funding: Rotherham Health Authority.
Conflict of interest: None.
(Accepted 13 June 1997)
Rotherham Health Authorities, Rotherham
Priority Health Services NHS Trust, Sheffield School of
Health and Related Research,
Correspondence to: Dr Tony Baxter
Barnsley Health
Authority,
References
1 Doll R, Peto R. Mortality in relation to smoking: 20
years' observation on male British doctors. BMJ
1976;ii:1525-36.
2 Doll R, Gray R, Hafner B, Peto R. Mortality in relation to
smoking: 22 years' observation on female British doctors.
BMJ 1980;i:967-71.
3 Dawber T R. The Framingham Study: the epidemiology of
atherosclerotic disease. Cambridge: Harvard University Press,
1980.
4 Shaper A G, Pocock S J, Walker M, Philips A N, Whitehead T P,
MacFarlane P W. Risk factors for ischaemic heart disease: the
prospective phase of the British Regional Heart Study. J
Epidemiol Community Health 1985;39:197-209.
5 Keys A. Seven countries: a multivariate analysis of
death and coronary heart disease. Cambridge: Harvard University
Press, 1980.
6 Shaper A G, Mann J W. Dietary recommendations for the community
towards the postponement of coronary heart disease. BMJ
1977;i:867-71.
7 Macmahon S, Peto R, Cutler J, Collins R, Surlie P, Neaton J,
et al. Blood pressure stroke and coronary heart disease. Part 1:
prolonged differences in blood pressure: prospective observational
studies corrected for the regression dilution bias.
Lancet 1990;335:765-74.
8 The Multiple Risk Factor Intervention Group. Mortality rates
after 10.5 years for participants in the Multiple Risk Factor
Intervention Trial. JAMA 1990;263:1795-1801.
9 WHO European Collaborative Group. Trial of multifactorial
prevention of coronary heart disease, final report.
Lancet 1986;i:869-72.
10 Rose G, Hamilton P J S, Colwell L, Shipley M J. A randomised
controlled trial of antismoking advice: 10 year results. J
Epidemiol Community Health 1982;36:2-8.
11 Farquhar J W. The community based model of lifestyle
intervention trials. Am J Epidemiol 1978;108:103-11.
12 Baxter A P, Milner P C, Hawkins S, Leaf M, Simpson C, Wilson K V,
et al. The impact of heart health promotion on coronary heart disease
lifestyle risk factors in schoolchildren: lessons learnt from a
community-based project. Public Health 1997;111:231-7.
13 Naidoo J, Wills J. Health Promotion: foundations for
practice. London: Bailliere Tindall, 1994.
14 Health Education Authority/Office of Population Censuses and
Surveys. Health and life-style surveys: towards a common
approach. London: Health Education Authority, 1990.
15 Cartwright A. Health surveys. London: King's
Fund, 1983.
16 OPCS. General household survey 1990. London:
HMSO, 1992.
17 Lessler J T, Kalsbeek W D. Non-sampling error in
surveys. New York: Wiley- Interscience, 1992.
18 Spackman M. Discount rates of return in the public
sector: economic issues. London: Government Economic Service,
1991.
19 Tolley K. Health promotion: how to measure
cost-effectiveness. London: Health Education Authority, 1993.
20 Cancer Prevention Study II. The American Cancer Society
prospective study. Statistical Bulletin-Metropolitan Insurance
Companies 1992;73(4):21-9.
21 Maynard A. Developing the health care market. Economic
Journal 1991;101:1277- 86.
22 Langham S, Thorogood M, Normand C, Muir J, Jones L, Fowler G.
Costs and cost effectiveness of health checks conducted by nurses in
primary care: the Oxcheck study. BMJ 1996;312:1265-8.
23 Wonderling D, McDermott C, Buxton M, Kinmonth A, Pyke S,
Thompson S, et al. Costs and cost effectiveness of cardiovascular
screening and intervention: the British family heart study.
BMJ 1996;312:1269-73.
24 Wonderling D, Langham S, Buxton M, Normand C, McDermott C. What
can be concluded from the Oxcheck and British family heart studies:
commentary on cost effectiveness analyses. BMJ
1996;312:1274-8.
25 Scandinavian Simvastatin Survival Study Group. Randomised trial
of cholesterol lowering in 4444 patients with coronary heart disease:
the Scandinavian Simvastatin Survival Study (4S). Lancet
1994;344:1383-9.
26 The West of Scotland Coronary Prevention Study Group.
Prevention of coronary heart disease with pravastatin in men with
hypercholesterolemia. New Engl J Med 1995;333:1301-7.
27 Lindholm L, Rosén M, Weinehall L, Asplund K. Cost
effectiveness and equity of a community based cardiovascular disease
prevention programme in Norsjö, Sweden. J Epidemiol Community
Health 1996;50:190-5.
28 Department of Health. Fit for the future: second
progress report on the Health of the Nation. London: Department
of Health, 1995.
29 Burke G L, Sprafka J M, Folsom A R. Trends in coronary heart
disease mortality, morbidity and risk factor levels from 1960 to 1986:
the Minnesota Heart Survey. Int J Epidemiol
1989;18:573-81.
30 Martin C A, Hobbs M S T, Armstrong B K. Trends in the incidence of
myocardial infarction in Western Australia between 1972 and 1982.
Am J Epidemiol 1989;129:655- 68.
Key Messages
Little is known about the cost effectiveness of focused, heart
disease health promotion projects in reducing cardiovascular risk
factors over a short period in small populations of adults Research was undertaken to estimate the impact of a heart
disease health promotion project - Action Heart - and relate the cost to
estimates of health gain Major differences were observed in changes in prevalence of
active smoking and consumption of low fat milk between the intervention
and control areas over four years The estimated cost per life year gained was £31 Further research is required to ascertain whether the changes
in risk factors will be sustained after the end of Action Heart
Rotherham S65 2QU
Tony Baxter, senior
registrar in public health medicine
Philip Milner,
director of public health
Mike Leaf,
deputy director of health promotion
Doncaster Gate Hospital,
Rotherham
S65 1DW
Keith Wilson,
professor
University of Sheffield,
Sheffield S1
4DA
Jon Nicholl, professor
Jenny
Freeman, statistician
Nicola Cooper,
research associate, health economics
Barnsley S75 2PY
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