Downloaded from jech.bmj.com on 1 October 2008 Glossary The concept of prevention: a good idea gone astray? B Starfield,1 J Hyde,2,3 JGe´rvas,4,5 I Heath6 1 Johns Hopkins University, ABSTRACT at risk of over-medicalization, to protect him (sic) 2 Baltimore, MD, USA; Victoria Over time, the definition of prevention has expanded so from new medical invasion, and to suggest to him Department of Human Services, 5 Melbourne, Australia; 3 Monash that its meaning in the context of health services is now (sic) interventions which are ethically acceptable’’. University, Melbourne, Australia; unclear. As risk factors are increasingly considered to be Gofrit et al. defined quaternary prevention as 4 Equipo CESCA, Madrid, Spain; the equivalent of ‘‘diseases’’ for purposes of intervention, ‘‘debriefing, quality assurance, and improvement 5 Canencia de la Sierra (Madrid), 6 the concept of prevention has lost all practical meaning. processes’’, which ‘‘complete the cycle of preven- Spain; Caversham Group This paper reviews the inconsistencies in its utility, and tion by collecting information about the processes, Practice, London, UK suggests principles that it should follow in the future: a multi-disciplinary analysis of the data, deriving Correspondence to: population orientation with explicit consideration of conclusions, and distributing them to all the Dr B Starfield, Professor of attributable risk, the setting of priorities based on involved bodies’’.6 Health Policy, 624 N Broadway, room 452, Johns Hopkins reduction in illness and avoidance of adverse effects, and Quaternary prevention has also been defined by University, Baltimore, MD the imperative to reduce inequities in health. cardiovascular disease experts as ‘‘rehabilitation or 21205-1990, USA; restoration of function’’, applicable to ‘‘those with [email protected] severe cardiovascular dysfuntion’’.7 These three The scope of prevention has changed over time. A definitions are not easily compatible. Accepted 9 December 2007 1967 textbook stated: ‘‘Prevention, in a narrow Identification of ‘‘risk factors’’ as part of sense, means averting the development of a prevention has been designated a new era in public pathological state. In a broader sense, it includes health and clinical medicine8 and as a new all measures—definitive therapy among them— professional activity of epidemiologists.910 Risk that limit the progression of disease at any stage of factors, such as elevated blood pressure, are now its course’’.1 A distinction was made between even considered as ‘‘diseases’’.11 interventions that avert the occurrence of disease The shift from public health to clinical disease is (primary prevention) and interventions that halt or evident in the historical development of the slow the progression of a disease or its sequelae at concept of prevention. Geoffrey Rose provided any point after its inception (secondary preven- the basis for a population orientation to reducing tion). risk factors associated with coronary heart disease, By 1978, the distinctions between types of arguing that only a small proportion of cardiovas- prevention had expanded to include primary cular events occur in individuals with high risk prevention to promote health prior to the devel- scores. He maintained that population-based pre- opment of disease or injuries; secondary prevention vention must be low cost, minimally invasive and to detect disease in early (asymptomatic) stages; avoid discomfort and pain. His arguments have and tertiary prevention to reverse, arrest or delay been used in ways never intended: to justify progression of disease.2 treatment of individuals in clinical settings.12 This Neither the 1967 nor the 1978 definitions used reflects the emergence of the concept of ‘‘preven- the terminology of ‘‘risk factor’’, but in 1998, the tive medicine’’, particularly in the US. Clinical World Health Organization, in addressing ‘‘dis- medicine, while increasingly adopting prevention ease’’ prevention, stated that it ‘‘covers measures as a field of activity, lacks a definition of not only to prevent the occurrence of disease, such prevention: the Guide to Clinical Preventive Services as risk factor reduction, but also to arrest its (US Task Force on Prevention) does not offer one progress and reduce its consequences once estab- despite increasing confusion about the boundaries lished’’. The Australian National Public Health between the different levels of prevention. The Partnership designated prevention as ‘‘action to World Health Organization did not include the reduce or eliminate or reduce the onset, causes, term ‘‘prevention’’ as a function of health systems, complications, or recurrence of disease’’.3 Several which are defined as ‘‘all the activities whose levels were defined: primordial prevention (‘‘pre- primary purpose is to promote, restore, and venting the emergence of predisposing social and maintain health’’.13 environmental conditions that can lead to causa- Is the concept of ‘‘prevention’’, with its increas- tion of disease; primary prevention; secondary ing focus on particular diseases and risk factors prevention; and tertiary prevention to improve (rather than on ill health in general), still useful? function, minimise impact, and delay complica- When so many people lack adequate access to tions’’). medical care for their manifest health needs, is it The Dictionary of Public Health defined preven- justifiable that routine disease check-up visits are tion similarly, but conceded that the distinction approaching half of all medical visits, as in the between levels ‘‘is more artificial than real’’.4 United States?14–16 Is intervention with four A recent addition to the lexicon of prevention is drugs, lifestyle advice and cardiac rehabilitation ‘‘quaternary prevention’’. The world organisation really prevention, as suggested by the title of a of family physicians (WONCA) defined quaternary published study ‘‘Secondary prevention for prevention as ‘‘an action taken to identify a patient patients after a myocardial infarction: summary 580 J Epidemiol Community Health 2008;62:580–583. doi:10.1136/jech.2007.071027 Downloaded from jech.bmj.com on 1 October 2008 Glossary of NICE guidelines’’?17 Is intervention to reduce the blood level prevention and cure are becoming increasingly indistinct. of a known ‘‘risk factor’’ (eg homocysteine) really prevention Physicians, as a profession, have always had the power to when it does not reduce the occurrence of the disease or define ‘‘diseases’’ and stages of diseases.29 30 For example, the improve overall health?18 Should controlling risk factors replace current definition of heart failure31 includes four stages. Obesity the conventional focus on controlling disease, even if it does not constitutes stage A, even in the absence of symptoms or necessarily improve health? Should medication (eg cerivastatin) structural changes in the heart. Stage B also constitutes being to improve surrogate outcomes in cardiovascular trials19 20 be ‘‘at risk of heart failure’’. Only stages C and D constitute considered ‘‘prevention’’ when its use is associated with fatal evident heart failure. States A and B are preheart failure – a rhabdomyolisis causing it to be withdrawn from the world ‘‘diagnosis’’ justifying medication. When drugs are promoted for market?21 Is it time for a new formulation? prevention and the number of patients at risk is very large, the As a result of marked changes in the organsation of health expanded exposure to the drug may lead to important harm.32 services and increases in knowledge about the genesis and The increasing attention to iatrogenic causes of ill health and management of disease, there is good reason to question the the resulting addition of ‘‘quaternary prevention’’ also point to differentiation of prevention from other aspects of health care. the need to explicitly include iatrogenesis as an influence on ill Clinical settings are increasingly moving towards population- health. based medicine. As clinical practices become larger, with defined Recommendations for clinical preventive services still focus populations, the realities of individual-based medical care now largely on the results of analyses of relative risk in individuals have to confront the principles of population-based care. not necessarily representative of the population or subpopula- Increased risk of an event based upon the presence of a tions.33 Furthermore, recommendations for risk factor screening ‘‘predisposing factor’’ with high relative risk may no longer be are made one by one, despite evidence that risk factors are not the main criterion for intervention. The ‘‘event’’ may be too independent of each other. On average, adult patients in the US uncommon in the population and hence not practical as a in the mid-1990s were estimated to have approximately 12 risk priority. Alternatively, the intervention to reduce excess risk, factors requiring approximately 24 preventive services—even while useful based on statistical associations in clinical trials, before the explosion of the concept of risks.34 A more recent may not be useful in other population groups not included in analysis, recognising some of the limitations of estimates of the trial.22 A prime example is the utility of statins for benefit, set several priorities for clinical prevention in the total ‘‘prevention’’ of recurrent myocardial infarct in men and the population based on ‘‘preventable burden’’ and cost-effective- absence of evidence for their utility in either primary or ness; none involved