When preventive health check-ups do more harm

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.

- Ganesan Karthikeyan

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.