Preventive Medicine and the "Road to Hell"1

Many of my patients are confused. So are many of my colleagues. Official bodies of experts barrage the media with pronouncements on what constitutes good preventive medicine: screening tests, eating or abjuring certain foods, avoidance of exposures to sun or environmental hazards, "correct" behaviors. Although they acknowledge that the data are, and always will be, imperfect, these experts try their best to direct people in the way that the evidence points-for now. This is all propelled by the desire to make people better, and to equip them with the information they need to make decisions. As a nation, we are wed to the concept of public education; we believe that the more information we have, the more likely we will be to make the right choices. Maybe that's true-but maybe it's not.

The dangers of changing data. Excluding those infamous villains propelled by venality, the majority of the aforementioned experts are well-intentioned, highly knowledgeable, caring, and concerned. However, in their zeal to serve, they may also do some real harm and vitiate whatever good they accomplish-if, as has so often been the case recently, the data change. Yes . . . hormone replacement therapy for women; no, dangerous! Yes . . .margarine better than butter; no . . . not really. Yes, mammograms for all; no . . . maybe not for all, just for some. If we persist in issuing so many-and so many contradictory-" preventive health dictates," we may lose all credibility for any.

The effects of human variability. Perhaps the greatest flaw in health information is that it is of necessity general and cohort-based in order that its promulgators may claim statistical (if not clinical) significance. (The difference between statistical and clinical significance is another source of great confusion; one may improve the therapeutic benefit of a regimen by over 25% and not really have done much.) General information must be tailored to the complex reality of individual, inevitably variant, human beings. This is a truth of which both doctors and patients need reminding in perpetuum. Yet another often-unarticulated reality is that, whatever the recommended test or intervention, the extreme variability of human agents administering and interpreting it will affect its risk-benefit ratio: whether lay or professional, these agents differ in their skills one from another and, importantly, from those involved in the study or studies on which the recommendations are based.

Delusions about the power of information. Moreover, health care decisions are not based on information alone but also on the emotional impact of that information: many of my patients need to believe, because of their fears of certain diseases, that screening for these disorders in some way prevents them as well as detects them. I shall never forget witnessing the bedside scene of a daughter berating her mother, now painfully afflicted with metastatic cancer of the breast, for not having had last month's routine mammogram-as if that act would have prevented the present horror. The rush of some members of the public to get screened for cancer or heart disease by profiteering CT scan centers, based on generic recommendations emphasizing the value of early detection, is propelled by the delusion of control through information, not by true knowledge.

We will all die of something. And finally, though by no means completely, there is an underlying deception in all of these pronouncements: that if we can detect a risk in a specific individual in time, and early detection or preventive behavior leads to a better chance for escaping that risk-as a result of regular mammograms, for example, a woman doesn't die of breast cancer-then the person will be all right in some sense. But he or she won't, after all. The woman who escapes breast cancer will ultimately die of something else. It may be a "better" cause of death (for example, extreme but active and fulfilled old age) or it may be something worse (such as amyotrophic lateral sclerosis . . . cerebrovascular catastrophe . . . crippling, painful, systemic rheumatologic disease . . . pancreatic cancer). Our misunderstanding of the significance of information is based in part on our "scientific" reliance on major cohort studies that have a verifiable end point with which none can quarrel: death. We are engaged in constant "wars" to prevent whatever is at the top of the "Most Common Causes of Death" list: coronary vascular disease, cancer, chronic lung disease, diabetes. We hack away at the top of the list through research, prevention, and therapy. But as soon as what we do to decrease the impact of the "top" disease works and the percentage of death by that cause declines, another must invariably rise to the top of the list because, by definition, 100% of those on the list have died of something. The numbers have to add up. We must also keep in mind the burden of suffering that prevention of one disease may cause by increasing the relative likelihood of another. The incidence of cancer is increasing in the non-Western world, according to recent news reports, largely because people are living longer, not dying as often of infection or malnutrition as they had in the past, and so are more likely to acquire cancer. This is both bad and good. I in no way argue for a youthful death to prevent later cancer or other diseases of aging. But people should be aware of what is likely to happen to them after they follow our recommendations for preventing any specific disease before they make decisions about whether to do so. Furthermore, this decision must be made in a more farsighted manner than one that involves no more than assessment of the risk-benefit ratio of false positives and negatives for the screening procedure in question (I mention this because of its recent emphasis in prostate-specific antigen screening). People have a right to know all their options, so far as they can be known.

A plea for wisdom in the dispensing of health information. So I worry about the panels of experts and their recommendations, whether they be for mammography- so very well discussed in this issue-or any other "health-promoting" thing. T. S. Eliot once wrote, "Where is the wisdom we have lost in knowledge? Where is the knowledge we have lost in information?"² Information, even knowledge, may not be enough to solve the tormented and multifaceted problem of the human condition in its relationship to disease and disability. We must make absolutely clear to patients when we give advice (which we must continue to do, based on better and better studies) that our advice is no more than the best we can do for now. We must promise only to the scientifically defined limits of reliability and applicability and warn patients that the advice may abruptly change when new information is forthcoming. That approach, rather than formulaic and emphatic dogma, would at least be honest, might be helpful to patients (though it would leave them dissatisfied), and ultimately would be wise.

References:

NOTES:

1

."The road to hell is paved with good intentions." Proverbial. Often wronglyattributed to Samuel Johnson.

2.

Eliot TS. Choruses from "The Rock."

The Complete Poems and Plays of T. S.Eliot.

London: Faber and Faber; 1969.