The Truth About Stress Tests

Sometimes I feel like the proverbial “anthropol0gist on Mars” as I discover more and more medical rituals that have little value  in diagnoses or improving health outcomes.  

Here is  a critical view of “heart stress tests” by David Newman, M.D., author of the very interesting book Hippocrates’ Shadow

From an article by David Newman:

“What about a stress test?”

The stress test is the elemental unit of diagnostic cardiology, and patients know of stress tests all too well. Unfortunately, both doctors and laypeople have been taught and trained wrong. I, for instance, was trained to believe in the general utility of stress testing. This was wrong. I was taught to obtain a stress test history, and to be comforted by normal results. Also wrong. I was taught to believe in the power of stress tests to establish safety and identify disease in low risk chest pain patients before they leave the hospital. Wrong.

Sensitivities and specificities for stress tests are often reported as being between 70% and 90%, but these numbers are misleading. Studies of stress tests have rarely used a proper gold standard (i.e. coronary angiography), and in the one reasonably sized, high quality study to be performed rigorously, the test’s sensitivity for coronary stenosis was 45%. It appears that flipping a coin would be a more sensitive mechanism for detecting CAD than relying on a stress test.

Stress tests are also terrible for predicting death or major cardiac events. In 2000, a preventive medicine group published the largest single experience of stress test screening for heart disease, with over 25,000 men (mean age 43). In the nearly ten years that followed the tests, 158 of the men suffered a cardiac death. The tests were completely normal in 40% of them.

via Special Report // The Truth About Stress Tests.

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