Statistically speaking, we declare anyone with repeated blood pressure readings of less than 120/80mm Hg as normal. We also diagnose patients' whose blood pressure is regularly greater than 140mg Hg (systolic or top number) or 90mm Hg (diastolic or bottom number) w/hypertension and start prescribing them medicine(s). But what about that vast chasm in between where patients have blood pressures of 120-139/80-89mm Hg? We talk to these patients about
TLC or therapeutic lifestyle changes, you know, more fruits & veggies, less sodium, more exercise, etc.
While there continues to be great debate as to what to do about blood pressures above normal, repeated studies have demonstrated that the risk of stroke, heart disease & cardiovascular mortality doubles w/each 20/10mm Hg increase over 115/75mm Hg. Yet, our
clinical inertia is such that we appear to need more evidence before we become more aggressive about our blood pressure lowering goals. I suppose we can thank ACCORD (Action to Control Cardiovascular Risk in Diabetes)
as noted last Thursday. But there is danger in taking one study of a specific (diabetic) population and applying it to the (non-diabetic) general population.
So to lend credence to the aforementioned increase risk for stroke associated with pre-hypertension, the authors
published online last week a meta-analysis of twelve studies (5 from Japan, 4 from the States, 2 from China & 1 from India) involving 518,520 participants followed from 3-32 years. Their conclusion? Pre-hypertension increases risk of stroke by 50%, even in the non-elderly. However, the authors should be thanked for breaking down the wide range of pre-hypertensive blood pressure into low (120-129/80-84mm Hg) and high (130-139/85-89mm Hg) groups because subanalysis of the data demonstrated that the increase risk of stroke was truly only attributable to the high end and not the low.
So perhaps we should start prescribing blood pressure lowering medications for persistent blood pressures greater than 130mm Hg or 85mm Hg. But before jumping to that conclusion (especially prior to the release of JNC8), remember that this was a meta-analysis and therefore only useful for developing hypotheses but gives no proof of cause & effect. Still, I wouldn't think twice about
seeing patients more often in order to convince them of the importance of lower blood pressures.
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