Have you been told by your health care professional that you have high blood pressure, high cholesterol or type 2 diabetes and you need to do something to improve your "numbers?" If so, it is likely their recommendations were based on national clinical practice guidelines written by experts in cardiovascular health.
On the face of it, following guidelines seems a very reasonable approach. What could be the problem?
Well, a recent evaluation of cardiovascular patient guidelines in the Journal of the American Medical Association (JAMA) reveals that only 12 per cent of the recommendations are based on randomized controlled trials (the highest level of evidence). In contrast, 54 per cent of the recommendations are based purely on opinion and consensus.
Here's what we know well: Evidence from the last 30 years provides pretty solid support that lowering what would be considered higher levels of blood pressure (above 160 to 170 mmHg systolic), especially in type 2 diabetics, reduces cardiovascular events (heart attacks and strokes) to what many, if not most, would consider a clinically important degree. Statins reduce the chance of cardiovascular events and one can control symptoms and improve outcomes when very high glucose levels are reduced.
But the evidence for reducing the risk of cardiovascular disease is not nearly as impressive or definitive when it comes to aggressively getting numbers below the commonly recommended lower number thresholds for blood pressure (