Did you know that the numerical value used or the cutoffs that are used to determine if you have a condition that needs treatment is set by expert panels of physicians but without any scientific processes. They are more haphazard than that: they involve value judgments, and financial interests. So as a result for example, the level of cholesterol that was acceptable was up to 240. That equalled about 10% of the population diagnosed with the condition. When the value was reduced to 200, the people that were between 200 and 240 which would have been in a normal range previously were now diagnosed as having high cholesterol and it brought the percentage to 30% of the population diagnosed with the condition needing treatment. That’s a significant increase and just like that you have 3 times the number of patients. The lower you set the cutoffs the more people it will include because it labels the less severe conditions that might never become a problem which are a lot more frequent. This leads to over diagnosis.

Over diagnosis is a relatively new problem in medicine. In the past, people didn’t go to the doctor when they were well – they tended to wait until they developed symptoms. Furthermore, doctors didn’t encourage the healthy to seek care. The net result was that doctors made fewer diagnoses than they do now. But the paradigm has changed. Early diagnosis is the goal. People seek care when they are well. Doctors try to detect disease earlier.

Over diagnosis began with the diagnosis and treatment of a common condition – hypertension or high blood pressure. Detecting and treating high blood pressure is one of the most important things doctors do. But it’s also true that they do too much of it. Some people are diagnosed and treated needlessly – they are over diagnosed. It is the first condition that started being diagnosed in people without symptoms. Prior to the late 20th century, doctors generally prescribed medicines only to patients with symptoms of disease. But hypertension changed that. Suddenly people with no health complaints – who perceived no health problems – were being given a diagnosis and prescribed treatment. This provided the opportunity to prevent symptomatic disease in some, but at the cost of making the diagnosis in others who were not destined ever to develop symptoms or die from hypertension. In other words, at the cost of over diagnosis.

Hypertension is defined by a numerical rule. If your blood pressure is above a certain number, you have hypertension. If it isn’t above that number, you don’t. You can be labeled simply because you are on the wrong side of a number, not because you have any symptoms. If a doctor is asked what is normal blood pressure, typically the answer will be 120/80 but doctors see blood pressures higher than this all the time. The question is; At what level is blood pressure abnormal? Most doctors would agree that a pressure of 160/90 is abnormally high. And we all would agree that 202/117 is really high, in fact really, really high. The benefit of treating very high blood pressure is great. But hypertension varies in degrees of severity, from almost normal blood pressure to very high. And the benefit of treatment is affected by the degree of hypertension.

So what? If there’s any chance of benefit, why not take the medication, right? One reason is money. Some people have to spend a lot of their income on medications. Another is some harm associated with treatment. There are downsides to being treated for hypertension, some more serious then others. Some medicine can cause fatigue, others can cause cough, others can impair sex drive. All of them can make your blood level too low, leading to light-headedness, fainting and falls. For the elderly major falls can be the start of a chain of events that lead to death. The balance between the potential benefit of treatment and the risk of over diagnosis is closely related to where a person falls on the abnormality spectrum – in other words, how high his or her blood pressure is – and how aggressively we choose to lower it……