Editors' Response—exporting failure

Shah Ebrahim and George Davey Smith

Our editorial described the limited effects of comprehensive cardiovascular disease prevention programmes, widely evaluated in the developed world, and questioned their relevance to developing countries.1

Dr Puska complains that we have not read the findings of the North Karelia study carefully enough. Interpretation of what is shown by the North Karelia study depends on understanding the nature of the intervention, the time frame over which changes were examined, and whether one is primarily interested in ‘explaining’ the changes observed within North Karelia without reference to other studies examining the same question. The intervention comprised five arms: health education, screening, a hypertension programme, ‘intensification of treatment’ (secondary prevention), and rehabilitation, and as such, was focused mainly on individuals rather than the population at large.2 As shown in Table 1 of our editorial, the reductions in risk factors were, in fact, very similar after 10 years intervention in the control and intervention communities.1 CHD mortality trends over the period 1969 to 1995 show a greater decline in North Karelia than the rest of the country, but the 95% confidence intervals for the slopes overlap.3 An intriguing pattern of decline is hidden in the overall trend. First, North Karelia experienced an almost immediate and rapid decline, a rise and a fall in CHD mortality (1971–1975). Second, rates of decline were significantly greater in the country as a whole than in North Karelia (1976–1985). Finally, death rates tended to approximate to each other (1986–1995). Such trends do not provide unambiguous support for the hypothesis that the intervention was effective.

Dr Puska suggests that we have not made the effort to go through the publications from the North Karelia group. We have made this effort, but like other readers we end up somewhat confused. For example one of the original North Karelia investigators, Jukka Salonen, dissented from the view held by the more enthusiastic members of the team that a favourable effect on mortality could be attributed to the intervention.4 Both Dr Puska and Dr White cite a paper5 which concluded that in Finland ‘changes in risk factors explained almost all of the decline in mortality from ischaemic heart disease in the 1970s, but in the 1980s the mortality declined more than predicted by changes in risk factors’. Obtaining a greater than expected payback is a remarkable achievement indeed, but one of the North Karelia project authors on this paper then went on to co-author a paper stating that ‘temporal trends in mortality from coronary heart disease are not adequately explained by the lifestyles of Finnish men and women'.6 Making the effort to go through the publications actually leads to increased uncertainty and confusion. We would suggest that it is precisely those commentators who have not taken the trouble to read the full range of publications who are the ones who repeat the glib—and traditional—declaration of victory that has emanated from some of the less critical members of the health promotion fraternity.

It is less well known than it should be that the North Karelia study was one of a family of studies using a similar protocol and launched by World Health Organization in 1974 called the Comprehensive Cardiovascular Community Control Programme (CCCP).7 These other programmes were run in Hungary, USSR, Switzerland, Norway, Italy, Yugoslavia and both German republics. Although the North Karelia project has generated many more publications than other comparable projects conducted over the last three decades, these other projects are worthy of our attention in making a balanced decision about what does and does not work. We are rather surprised that neither Dr Puska nor Dr White refer to these.

Most of these CCCP studies did not find their way into accessible peer-reviewed scientific journals and those that did, together with other related studies demonstrated methodological weaknesses and generally rather disappointing findings.8,9 A WHO report on the CCCP studies edited by Dr Puska10 attempted to put a gloss on the effectiveness of the projects that was not supported when the effort was made to read the tables actually published in the book. For example in the case of the Swiss project an increase in antihypertensive therapy in the intervention communities was said not to be ‘reflected in mean blood pressure levels’. This is something of an under-statement; a table in the book shows that blood pressure showed a significant relative increase in the intervention communities! The text suggests that in the then German Democratic Republic male CVD mortality was favourably influenced, whereas a table in the book shows that the intervention community was experiencing a decline in CVD mortality before the onset of the project which reversed to an increase, whereas the control community was experiencing a rise in CVD mortality which continued after project initiation.

The overall findings of these projects, as opposed to cherry-picking the results of the one apparent ‘success’, are rather similar to those of our systematic review of randomized controlled trials of multiple risk factor interventions, with a relative risk reduction for CHD mortality of –4% (95% confidence intervals –11%, +4%) demonstrating how limited the effects of this approach are.11

The 1973 editorial Shot-gun prevention?, cited by Dr Puska, suggested that two questions remained to be answered in the context of prevention programmes of this nature: do most cases fall into the high-risk category, and is there evidence that intervention is beneficial?12 We now have the answers to these questions: No, and Not very. Far from reiterating the arguments in this old editorial we used the evidence that has accumulated over the last 30 years to provoke scientists and policy makers to think seriously about whether our experience and disappointments in not achieving more with CHD and stroke prevention programmes should be applied in much poorer countries, or whether we should carry on wearing the rose-tinted spectacles of those authorities who fail to consider the totality of the evidence.

We greatly appreciate Dr Puska's professional and amateur fire-fighter story; if the fire is put out, who cares how it was done, particularly if the benefit was achieved for less money? But in central Europe and the former USSR, CHD and stroke are increasing dramatically, notwithstanding the major investments that were made in comprehensive preventive services—but presumably Dr Puska would argue that the fire-fighters in these countries are not as good as in Finland. There is no doubt that risk factor declines have occurred, both in Finland and in other countries, over the last two decades and these explain, in part, the declines in CHD mortality.13 The MONICA studies have also demonstrated that case-fatality declines have occurred suggesting that better medical care has also played an important role.14

It is vital that we understand what drives cardiovascular disease trends upwards and downwards if we are to achieve better CVD control. In developing countries with virtually no resources for prevention of non-communicable diseases (NCD) a comprehensive approach, as used in Mauritius, may only be feasible if funded by research programmes.15 In Mauritius, cholesterol reduction was achieved by switching the supply of cooking oil—a population strategy—and not by dietary advice to individuals and families. The cost-effectiveness of these two strategies is vastly different and while wealthy developed countries may value the potential synergy between population and individual risk factor intervention, it is not without cost.

We agree with Dr Beaglehole that surveillance systems are an essential component of any prevention strategy and welcome WHO's work in developing better NCD systems particularly in the third of countries where DALY estimates can only be guesses.16 The various networks, described by Dr White, that have arisen following the CCCP initiative are clearly valuable in providing a range of frameworks for action and research. We are grateful to Dr White for correcting our misrepresentation of the Ottawa Charter which, unlike other policies of that time, provided the ideological template for the 53rd World Health Assembly resolution.

Unfortunately, our best guesses about what to do to reduce the levels of common risk factors in the population—exemplified by the complex comprehensive community interventions tested in the COMMIT study, the Stanford Studies, the Minnesota and Pawtucket Programmes—do not appear to deliver. Surely these intervention failures teach us that their application in poorer countries is unlikely to be of much help, but will certainly use resources. We therefore support Dr Beaglehole's view that we should try to find out how we could do better.16

References

1 Ebrahim S, Smith GD. Exporting failure? Coronary heart disease and stroke in developing countries. Int J Epidemiol 2001;30:201–05.[Free Full Text]

2 Puska P. The North Karelia project: an attempt at community prevention of cardiovascular disease. WHO Chron 1973;27:55–58.[ISI][Medline]

3 Puska P, Vartiainen E, Tuomilehto J, Salomaa V, Nissinen A. Changes in premature deaths in Finland: successful long-term prevention of cardiovascular diseases. Bull World Health Organ 1998;76:419–25.[ISI][Medline]

4 Salonen JT. Did the North Karelia project reduce coronary mortality? Lancet 1987;2:269.

5 Vartiainen E, Puska P, Pekkanen J, Tuomilehto J, Jousilahti P. Changes in risk factors explain changes in mortality from ischaemic heart disease in Finland. Br Med J 1994;309:23–27.[Abstract/Free Full Text]

6 Forsen T, Eriksson JG, Tuomilehto J, Teramo K, Osmond C, Barker DJ. Mother's weight in pregnancy and coronary heart disease in a cohort of Finnish men: follow up study. Br Med J 1997;315:837–40.[Abstract/Free Full Text]

7 Davey Smith G. Comprehensive Cardiovascular Community Control Programmes in Europe. Abstracts on Hygiene & Communicable Diseases 1989;64:388–90.

8 Maschewsky-Schneider U, Greiser E. Primary prevention of coronary heart disease versus health promotion—a contradiction? Ann Med 1989;21:215–18.[ISI][Medline]

9 Steinbach M, Constantineanu M, Georgescu M et al. The Bucharest Multifactorial Prevention Trial of Coronary Heart Disease—ten year follow-up: 1971–1982. Med Interne 1984;22:99–106.[Medline]

10 Anonymous. Comprehensive cardiovascular community control programmes in Europe. Geneva: WHO, 2001.

11 Ebrahim S, Davey Smith G. Systematic review of randomised controlled trials of multiple risk factor interventions for preventing coronary heart disease. Br Med J 1997;314:1666–74.[Abstract/Free Full Text]

12 Editorial. Shot gun Prevention? Int J Epidemiol 1973;2:219–20.[ISI][Medline]

13 Anonymous. Ecological analysis of the association between mortality and major risk factors of cardiovascular disease. The World Health Organization MONICA Project. Int J Epidemiol 1994;23:505–16.[Abstract]

14 Tunstall-Pedoe H, Vanuzzo D, Hobbs M et al. Estimation of contribution of changes in coronary care to improving survival, event rates, and coronary heart disease mortality across the WHO MONICA Project populations. Lancet 2000;355:688–700.[ISI][Medline]

15 Dowse GK, Gareeboo H, Alberti KG et al. Changes in population cholesterol concentrations and other cardiovascular risk factor levels after five years of the non-communicable disease intervention programme in Mauritius. Mauritius Non-communicable Disease Study Group. Br Med J 1995;311:1255–59.[Abstract/Free Full Text]

16 Beaglehole R. Global cardiovascular disease prevention: time to get serious. Lancet 2001;358:661–63.[ISI][Medline]





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