Every day, people are exhorted to undergo “preventive” health check-ups. These come in the form of executive check-ups, prevention “camps”, and bundled packs which promise more tests for less money. While many tests are good barometers of health and help modify diet and lifestyle, many others are unnecessary. Some, such as the treadmill exercise test, may even be harmful. What is wrong with having a preventive check-up? After all, wouldn’t it be better to identify problems before they become serious? The answer to this question rests on two fundamental requirements. First, the ability of the test to identify individuals who are truly at risk of health problems in the future. And second, the availability of proven treatments that will reduce this risk.
Most tests are far less accurate than one imagines. As an example, the treadmill test — a part of preventive health check-ups — is particularly notorious. It misses 30-40% of people who have heart disease and falsely identifies 30-40% of people as having problems. In addition to not serving its purpose, it leads to many individuals being unnecessarily investigated and treated. This results in much anxiety, many needless procedures, and serious complications in some unfortunate people. The false-positives problem is further magnified when the test is used in people without known health issues, as in the case of preventive check-ups.
The second issue stems from the misperception that obtaining more information automatically translates to better health outcomes. Often, the motivation for people to get themselves tested is anchored in the belief that they will get to know if “something is wrong”. But even if a test is accurate (which is rarely the case), the information that it provides must lead to actionable knowledge. And the actions should lead to better health. This holds true for tests such as blood sugar, cholesterol and blood pressure measurement. But this is not the case with tests such as the treadmill test. Among those who are identified as having disease by a positive test, studies have failed to show any benefit of treatment, particularly in the absence of symptoms. To complicate matters, many more people end up getting unnecessarily treated, and often suffer the side-effects of such treatment, leading to increased health care costs without improving outcomes. Most physician societies around the world do not recommend the routine use of the test as part of preventive health check-ups.
Tests used for screening the general population for a disease must meet a higher bar than tests used to diagnose the disease in patients with symptoms. First, they have to be accurate — picking out most or all with the disease while keeping false alarms to a minimum. Second, the strategy of treating the people with a “positive” screening test (and not treating the others) should yield a net benefit to society in the long run. This needs robust evidence generated through rigorous research. Some tests such as those for cervical and breast cancer screening are based on strong scientific evidence. However, hard lessons have been learnt when indiscriminate use of testing has been allowed in some other cases. In South Korea, the seemingly innocuous addition of ultrasound screening for thyroid cancer in the early 2000s resulted in a 15-fold rise in detections. Subsequent analyses found that while many more surgeries for thyroid cancer were performed than before, deaths due to the disease remained unchanged — an ominous sign of over-diagnosis. Many suffered complications, such as vocal cord paralysis, due to unnecessary surgery. Being a small country with good population-level data, South Korea was able to rectify the problem. However, given India’s size and population, the magnitude and consequences of inappropriate screening may largely go unnoticed.
{{/usCountry}}Tests used for screening the general population for a disease must meet a higher bar than tests used to diagnose the disease in patients with symptoms. First, they have to be accurate — picking out most or all with the disease while keeping false alarms to a minimum. Second, the strategy of treating the people with a “positive” screening test (and not treating the others) should yield a net benefit to society in the long run. This needs robust evidence generated through rigorous research. Some tests such as those for cervical and breast cancer screening are based on strong scientific evidence. However, hard lessons have been learnt when indiscriminate use of testing has been allowed in some other cases. In South Korea, the seemingly innocuous addition of ultrasound screening for thyroid cancer in the early 2000s resulted in a 15-fold rise in detections. Subsequent analyses found that while many more surgeries for thyroid cancer were performed than before, deaths due to the disease remained unchanged — an ominous sign of over-diagnosis. Many suffered complications, such as vocal cord paralysis, due to unnecessary surgery. Being a small country with good population-level data, South Korea was able to rectify the problem. However, given India’s size and population, the magnitude and consequences of inappropriate screening may largely go unnoticed.
{{/usCountry}}The common man also needs to understand the perils of indiscriminate testing. Doctors are, in general, well meaning. But they face intense pressure to be seen as doing something rather than simply providing reassuring advice. Our ability to prevent untoward health outcomes is imperfect. Not recommending a test of dubious value should not be conflated with incompetence or, worse, punished as malpractice. A more public endorsement of the importance of scientific evidence and evidence-based policy and practice will go a long way in changing societal opinion. In the meantime, we should update the tests required for annual check-ups and restrict reimbursement to just the ones that have scientific proof of benefit.
Ganesan Karthikeyan is professor of cardiology, AIIMS-Delhi, and the executive director of the Translational Health Science and Technology Institute, Faridabad. The views expressed are personal