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Are regular health checks good for you?

By Sebastian Rushworth, M.D. | June 30, 2021

Regular health checks (a.k.a routine visits) are probably the bane of many a primary care physician’s existence. I can’t imagine many things more boring than running through a standardized list of questions with a patient who feels absolutely fine, then going through a list of lab values that are almost invariably within the normal reference range, and finally topping it off with a perfunctory physical examination. Nothing converts a highly trained professional into an unthinking automaton more than the regular health check.

Of course, the physician’s feelings about regular health checks aren’t really what matters (except in so far as they cause physicians to choose not to work in primary care, and thereby cause a shortage of primary care physicians). What matters is whether the regular health check results in objective benefits for the patient. Well, do they?

A review was recently published in JAMA (the Journal of the American Medical Association) that sought to answer that question. Regular health checks are a big part of what primary care physicians do in many countries. In the US for example, 8% of doctor’s appointments are for a regular health check. This means that a lot of money is poured into them, and it therefore makes sense to try to figure out whether or not they actually do any good. Otherwise that money could be better used elsewhere, like for example launching Jeff Bezos into space.

The review included both randomized trials and observational studies, with the only requirements for inclusion being that a study have at least 200 participants, that there be a control group, that the health check be conducted in a primary care clinic, and that it be a “general” health check, i.e. not designed to screen specifically for any one disease. 19 randomized trials and 13 observational studies were identified. The smallest study had 240 participants, while the largest had almost 500,000 participants, and the length of follow-up varied from six months to thirty years. The oldest included study was published in 1973, and the most recent was published in 2017. Virtually all were carried out in western Europe or north America, with a disproportionately large proportion of the studies being carried out in Denmark, because apparently the Danes are disproportionately interested in health screening.

The frequency of the health check varied quite a lot. Some of the studies had a single visit, some had a visit annually or bi-annually, and some had irregular intervals.

So, what were the results?

13 randomized trials studied the effect of health checks on mortality, and eleven of these failed to show any benefit. This includes the study that ran the longest, a Danish trial with almost 18,000 people that provided health checks at baseline and then after five years and again after ten years. It failed to show any difference in mortality after thirty years. It also includes the largest study, another Danish trial with almost 60,000 people that provided health checks at baseline and again five years out (and also at the one year and three year marks for those deemed to be at high risk). It failed to show any mortality benefit after ten years of follow-up.

As mentioned, two of the thirteen studies did show a mortality benefit. The larger, another Danish study with 50,000 participants, which provided a single health check and then followed participants for five years to see what happened, showed an extremely marginal benefit (10% vs 11 % dead five years out), but the result only just crossed the threshold for statistical significance and could thus easily be a fluke. The other of the two was a smaller study with 4,195 people conducted in the US, which provided a health check at baseline and at one year out. It showed an improvement in mortality at two years (8% vs 11%) and four years (19% vs 22%).

Overall, though, I think it’s safe to conclude that the totality of studies that have so far been done of regular health checks fail to show that they result in any reduction in mortality. Of course, whether you’re dead or alive isn’t the only thing that matters. So let’s look at other outcomes too.

Five randomized trials looked at whether regular health checks helped prevent cardiovascular disease and cardiovascular events (a.k.a. heart attacks and strokes). All five failed to find any benefit. This is a bit odd, since one rationale for regular health checks is that they catch problems like high blood pressure and high cholesterol early, one major goal of which is to prevent cardiovascular events.

Four randomized trials and six observational studies did seek to understand whether the health checks increased detection of disease. A randomized trial conducted in Denmark (of course), in which 1,104 participants aged 45-64 were randomized to either a health check or “usual care” (i.e. don’t bother the doctor unless you feel sick) and then followed for one year, the health check had resulted in more than twice as many people being treated with anti-depressants (5% vs 2%). As I’ve written about previously, anti-depressants don’t work (better than placebo), but do result in significant side effects, so it’s questionable whether this is a good thing.

The health check did not however result in an increase in the diagnosis of high blood pressure, hypercholesterolemia (high cholesterol), or diabetes. Which is a bit surprising, quite frankly. Other trials did find a difference, however. An American trial in which 906 adults were randomized to a single health check or usual care and then followed for a year found that the health check resulted in a significant increase in the number of people diagnosed with high blood pressure (14% vs 10%). A British observational study including over 85,000 people found that attending regular health checks was associated with an increased likelihood of being diagnosed with high blood pressure, diabetes, and chronic kidney disease. Participants were also more likely to be diagnosed with hypercholesterolemia and treated with statins.

So the totality of evidence suggests that regular health checks do result in an increase in the number of people being given diagnoses and thus the number of people being put on medical treatment. But they don’t improve mortality or the frequency of cardiovascular events. That is strange, isn’t it? How do we explain that?

Here’s what I think.

Firstly, some of these diagnoses don’t actually result in any treatment. Take chronic kidney disease, for example. As people age, their kidneys gradually wear out. Once your kidneys’ capacity is at around 70% of the normal value in a healthy young person, you will be diagnosed as suffering from “chronic kidney disease”. Luckily, the kidneys have an enormous amount of spare capacity, and you don’t actually develop any symptoms until the kidneys are down to 10 to 15% of their original capacity. Most people who have been diagnosed with chronic kidney disease die of other causes long before their kidney function gets to that point. So regular health checks might increase the number of people diagnosed with chronic kidney disease, but the diagnosis doesn’t actually change anything in reality (except for the psychological harms of now thinking that you have a chronic disease, of course).

Secondly, there are many diagnoses that are treated, but where the benefits of treatment are so marginal that it isn’t clear whether treatment actually improves overall outcomes. This applies to mildly elevated blood pressure and blood sugar. Treating very high blood pressure and very high blood sugar is undoubtedly a good thing. But when they are only marginally raised, then treatment is much more questionable, and it’s not clear that the benefits outweigh the harms. The reason this is relevant is that most of the people identified with these conditions through health checks are at the milder end of the spectrum, and thus statistically unlikely to benefit from medical interventions.

Another condition that falls in to this category is the aforementioned hypercholesterolemia. Reducing cholesterol levels in the blood results in a reduction in deaths from heart disease (at least, that’s what the trials produced by the corporations that own the cholesterol lowering drugs say), but it doesn’t result in a reduction in overall mortality. Which does rather beg the question why we even bother to treat high cholesterol.

Thirdly, if regular health checks increase diagnoses and thus increase drug prescriptions, then they also increase the problem of polypharmacy, which is now a leading cause of death. Polypharmacy (taking many drugs simultaneously) frequently cancels out the benefits seen in clinical trials, where unusually healthy and young patients are being treated with a single drug or just a few drugs (i.e. a situation very far from the clinical reality).

It is thus easy to see how regular health checks could result in an increase in diagnoses and an increase in prescriptions without there being any noticeable improvement in survival.

Let’s move on and look at some more results.

Overall, health checks were associated with small improvements in blood pressure and cholesterol, as would be expected given the increase in prescriptions. However, it is hard to see what the value of an improvement in a surrogate marker is if there is no actual improvement in survival.

There was also a consistent increase in the uptake of disease specific screening services in people who took part in health checks. Which intuitively sounds like a good thing, except that again the reality is far more complicated. As I’ve written about before, both breast cancer screening and prostate cancer screening harm far more people than they help, and don’t result in any reduction in overall mortality. So increasing uptake of screening interventions can actually be a bad thing overall. It all depends on which particular screening interventions are being recommended.

Ok, let’s sum up. Regular health checks result in an increased probability of receiving a diagnosis and an increased probability of being put on drugs. They do not however improve longevity. With that being the case, the increase in diagnoses and drug prescriptions is of questionable value, and might even be a net negative, when side effects of the drugs and the negative psychological consequences of thinking of yourself as someone with a “chronic disease” are considered.

June 30, 2021 - Posted by | Science and Pseudo-Science, Timeless or most popular

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