A book published recently and entitled Overdiagnosed: Making People Sick in the Pursuit of Health, by three reputable physicians (H. Gilbert Welch, Lisa M. Schwartz, and Steve Woloshin), argues forcefully that the nation is spending too much money on preventive care. This is doubtless regarded as heresy in some circles: the orthodox view is that prevention is the key to economizing on the expenses of health care: “an ounce of prevention is worth a pound of cure.” The recent health care reform act seeks to promote preventive care.
Preventive care does reduce health costs in some cases, but not in all, and maybe not in most. The costs of prevention have to be weighed along with the benefits. And private and social costs have to be distinguished. Subsidy programs such as Medicare reduce the private costs of medical treatment to patients, but the social costs are not reduced; their incidence is merely shifted.
Generally, preventive care has two phases: screening and treatment. The former might seem inexpensive, both in monetary cost and in risk to health, but is not, and for two reasons: the number of people who do not have a condition that is screened for invariably greatly exceeds the number of people who have the condition, so that the cumulative costs of screening are high. And screening creates anxiety, both anxiety over the outcome and anxiety over what to do if the test for the disease in question is positive. An example is the blood test for prostate cancer. It turns out that a huge percentage of men have prostate cancer, but that most of the cancers are benign. The treatments have serious side effects, so for many (especially for elderly) men diagnosed with prostate cancer it is uncertain what the best course of action is. Another example of dubious preventive care is the treatment of mildly elevated blood pressure: blood pressure medicine has to be taken daily and of course must be paid for by someone, and has side effects though less serious ones than prostate treatments, while the benefits in reducing the risk of heart attacks or strokes are modest (unlike the case of highly elevated blood pressure). There are many other examples in which the net benefits of screening for medical conditions followed by treatment if the results of the test for the disease are positive are slight or negative.
The tendency has been to move the goalposts: to screen for lesser and lesser abnormalities, even though the lesser the abnormality the lesser the expected disease cost to the patient and so the less likely the screening and follow-up treatment are to provide net benefits. Moreover, mild abnormalities are far more common than severe ones, so that moving the goalposts greatly increases the number of persons who have to be screened. When the threshold for excessive cholesterol was lowered from 240 to 200, the number of Americans with excessive cholesterol increased by almost 43 million and all of them are recommended to take drugs to reduce their cholesterol, even though the benefits for persons who are not at high risk of heart disease for other reasons are highly uncertain—yet many of these persons are taking the drugs along with persons who can anticipate a significant benefit. The increased prevalence of screening and preventive treatment has increased the health awareness of Americans and by doing so has increased the innate anxiety that people feel about sickness and mortality.
Ordinarily we don’t question people’s consumption choices; and it might seem to follow that if people want to take, say, blood pressure medicine to prevent mild hypertension they should be assumed to be maximizing their utility and we should let them alone. But there are reasons to think that screening and treatment of persons who flunk screening tests are excessive from the standpoint of overall social welfare—that aggregate utility would be increased by reallocating many of the resources now used for screening and preventive treatments to other activities.
We can identify these reasons by considering the full range of factors, other than cost-benefit analyses that support particular forms of screening and preventive treatment. These factors are the incentives of medical researchers (many subsidized by government), health care providers (importantly including pharmaceutical manufacturers), medical malpractice lawyers, American cultural attitudes, our democratic political system, and patients who do not pay the full costs of their medical care. Advances in medical research enable more abnormalities to be discovered sooner—the PSA test for possible prostate cancer is an example—and to be treated. Physicians and other health care providers have an incentive to increase the demand for their services by creating new screening procedures and preventive treatments, although to the extent that preventive care does improve health (as much of it does), acute-care health providers face reduced demand for their services. But apart from dentistry, it is hard to think of areas of health in which preventive care has reduced the overall demand for treatment.
Although preventive care sometimes involves surgery, as in the case of prostate cancer and other cancers that may be benign, usually it involves treatment with drugs, and thus is strongly promoted by the pharmaceutical industry, often by advertising directly to the consumer.
Fear of medical malpractice drives physicians to order tests for low-probability conditions, lest they be sued for failure to diagnose a treatable condition.
Distinctive features of American culture include a strong commitment to business models of economic activity, a high correlation between income and prestige, competitive drive, and a rejection of fatalism. The medical profession, like the legal profession, has embraced a business as distinct from a professional model of service. In a business model, success is measured by profit. Physicians embrace opportunities for increasing their incomes by increasing the demand for their services.
Americans value longevity not only for the utility that additional years of life confer regardless of how long others live, but as a field of competition: prestige attaches to beating one’s contemporaries in the race to live as long as possible. And this turns out to be for many people a very cheap competition because other people are paying for their medical treatments. The subsidization of the old by the young in the Medicare program increases the demand for screening and preventive care by a politically prepotent voting bloc that has been able to shift most of its medical costs to others. Legal restrictions on exclusions in health insurance policies, and the tax subsidy of employer-provided health benefits, create further gulfs between the costs of medical care to particular persons and what they pay for it.
So not only is there compelling evidence of what Welch and his coauthors call overdiagnosis; there are good reasons to believe the evidence because the incentive structure for screening and preventive care makes overdiagnosis a theoretical prediction as well as an empirical reality.