Public Health versus Individual Health

Over many years of intermittently reading various medical journals I began to notice that the arguments in favor of public health measures were often based solely on society-wide benefits. The effects are usually small on an individual basis and only matter when applied to a large population. As reported in the popular press, the recommendations are simplified to do this because it will make you live longer.

The arguments in the journals tend to go like this:

  1. The relative risk of behavior X resulting in disease Y is 1.07, which means that 2,057 more individuals are expected to die per year from disease Y in the US and resulting an additional $158M over ten years in medical costs. Public health recommendations should be issued to discourage behavior X. Taxation or other disincentives should be considered.
  2. Diagnostic test W reduces deaths from disease Z with an odds ratio of 0.89. With (target) population-wide screening with test W, 3,700 fewer individuals will die per year from disease Z and there will be an increase of QALYs (quality-adjusted life-years) by 29,000. Universal screening will cause 580 deaths and 5,700 complications, 1,400 of which will be severe. Primary care physicians should advise their patients in the target population to be screened by test W.

What is missing is any consideration of an individual’s risk tradeoffs. A relative risk of 1.07 in example #1 means one is 7% more likely to contract disease X. A person may decide that a 7% increase in the chance of getting some obscure disease is not worth giving up behavior Y. An odds ratio of 0.89 in example #2 means the chances of dying from disease Z is reduced by about 11%. Someone might reasonably decide that modest reduction is not worth the pain, expense, or hassle of getting diagnostic test W.

The reasoning applies to all manner of public health recommendations: medications, vaccines, dietary guidelines, diagnostic tests, and other therapeutic interventions. Just because it saves money or trouble for the healthcare system or for the nation as a whole doesn’t mean it’s right for you.

Regarding disease screening specifically, in an op-ed a professor of medicine at Dartmouth notes that

Screening the apparently healthy potentially saves a few lives (although the National Cancer Institute couldn’t find any evidence for this in its recent large studies of prostate and ovarian cancer screening). But it definitely drags many others into the system needlessly — into needless appointments, needless tests, needless drugs and needless operations (not to mention all the accompanying needless insurance forms).

This process doesn’t promote health; it promotes disease. People suffer from more anxiety about their health, from drug side effects, from complications of surgery. A few die. And remember: these people felt fine when they entered the health care system.

Furthermore, there is the replication crisis in medicine, which means that many of the results that lead to public health recommendations turn out to vanish upon closer inspection. The science is not settled, as we’ve seen with the government’s dietary guidelines.  As John Ioannidis pointed out in a video in that linked post, odds ratios have a funny way of converging on 1 (no correlation) when other researchers attempt replication. This image, captured from his talk, shows what happens to odds ratios as investigators dig deeper:

Everyone’s situation is unique. None of this is meant to imply that any particular test, medication, procedure, or dietary recommendation is not appropriate for a given person. However, one should be aware that the criteria used for making these recommendations do not necessarily align with the value of any specific intervention for the individual.

The more thoughtful and careful physicians take a patient’s circumstances into account but are also bound by the best practices set by professional organizations and governments. Even if it’s true that something is good for public health, that doesn’t mean it’s good for you. Next time your doctor recommends a ‘routine’ test or prescribes a drug because the guidelines say so, you might want to ask how it will help you.

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Author: drlorentz

photon whisperer & quantum mechanic

4 thoughts on “Public Health versus Individual Health”

  1. The various flu vaccines are a concrete example of the public health phenomenon. This recent paper on the 2017-18 flu season provides some interesting examples. Table 5 from the paper shows that many of the odds ratios (OR) are close to 1, meaning the vaccine made little difference. Even an odds ratio of 0.5, typical of the best cases, may not be a compelling reason for many people to get vaccinated.

    In some cases the OR is greater than 1, meaning the vaccine was correlated with increased incidence of disease. Note the OR of 1.36 for coronavirus (not SARS-CoV-2, the cause of COVID-19). The author attributes this to “virus interference”:

    The virus interference phenomenon goes against the basic assumption of the test-negative vaccine effectiveness study that vaccination does not change the risk of infection with other respiratory illness…

    He concludes,

    Vaccine derived virus interference was significantly associated with coronavirus and human metapneumovirus; however, significant protection with vaccination was associated not only with most influenza viruses, but also parainfluenza, RSV, and non-influenza virus coinfections.

    One has to wonder if having received a seasonal flu vaccine made people more susceptible to getting the WuFlu.

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  2. I follow what you are saying, but I will counter it with the experience of one man.

    drlorentz:
    Everyone’s situation is unique. None of this is meant to imply that any particular test, medication, procedure, or dietary recommendation is not appropriate for a given person. However, one should be aware that the criteria used for making these recommendations do not necessarily align with the value of any specific intervention for the individual.

    Dad survived five cancers, on account of screening that caught them early.  After early diagnosis with diabetes, he managed well, kept strictly to the recommended regime, and never medicated for that condition.  His heart condition was caught early, monitored, and then, after he survived quintuple bypass surgery, he had a medicine that he took afterwards.

    Mama and I and our whole family had twenty good years with Dad that would have been fewer years and not such good years if he had not had the benefit of modern suburban American healthcare.

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  3. MJBubba:
    Dad survived five cancers, on account of screening that caught them early.  After early diagnosis with diabetes, he managed well, kept strictly to the recommended regime, and never medicated for that condition.  His heart condition was caught early, monitored, and then, after he survived quintuple bypass surgery, he had a medicine that he took afterwards.

    Mama and I and our whole family had twenty good years with Dad that would have been fewer years and not such good years if he had not had the benefit of modern suburban American healthcare.

    Right. I completely understand that. Screening, drugs, and treatments can be a great boon. Many have benefited from modern medicine – no question about it. I’m grateful it is as good as it is.

    Also, the public health considerations are important. Especially in a world where much of medicine is socialized, including in the US, the public health calculus can result in adverse consequences for individuals. For one thing, the incentives are to reduce costs because costs are socialized. In addition, public health officials are unable to make the individualized tradeoffs that people must make for themselves.

    Cholesterol level X means the patient should be on statins. That’s good for holding down Medicare costs and he might have an increase in life expectancy of 1.5 years. But maybe the patient doesn’t like the side effects. Those side effects are not life-threatening. Only the patient is competent to make the tradeoff between a statistical increase in life expectancy and a higher quality life that might be shorter.

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  4. drlorentz:
    Only the patient is competent to make the tradeoff between a statistical increase in life expectancy and a higher quality life that might be shorter.

    Agreed.  I could cite several anecdotes of people who switched doctors on account of pressure to take unwanted medications.  In a couple of cases these were ill-advised choices, but, most of the time these patients made good decisions.

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