Regular followers of SIRC's Media Watch page will no doubt remember a recent piece Too fat to die that discussed the US military's rather selective adaptation of the BMI guidelines. By simply adjusting BMI values at which an individual was considered to be 'over-weight', troops with a BMI of 25-27 were reclassified as fit enough to fight.
An article in the BMJ, US guidelines say blood pressure of 120/80 mm Hg is not "normal", outlines yet another example of how the goal posts are being shifted. Previously a blood pressure of 120 over 80 was considered normal. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) has now re-evaluated this diagnosis. With a blood pressure reading of 120 over 80 you are now suffering from a new condition: 'pre-hypertension'. You are now officially sick. Having contracted your 'new ailment' you now need to exercise, lose weight, reduce your consumption of sodium and alcohol and switch to a diet high in fruit, vegetables, potassium and calcium. Rather drastic measures you might think when just a week ago you were fine.
While reducing instances of high blood pressure is indeed a laudable aim one has to question the rationale behind redefining once healthy sections of the population as now being at risk. As the BMJ article suggests, a number of doctors have reservations about the new guidelines:
One physician said he used to tell patients their blood pressure was normal at 120/80 mm Hg and send them home happy. Now, was he supposed to tell them they had pre-hypertension, which they would interpret as a disease?
Is it really desirable to encourage more of the 'worried well' to camp out in already over-crowded waiting rooms? Furthermore, with home monitoring now encouraged hundreds of would be patients will be checking the LCD readings on their DIY blood pressure devices believing that they now have a 'problem'. A news item in Reuters suggested that while some studies have shown that home monitoring is a successful tool in helping people to lower their high blood pressure, a recent study has identified a problem with the accuracy of these instruments. This will surely not help.
Melissa J. Goalen, a nurse practitioner at the Mayo Clinic in Jacksonville, Florida, tested more than 100 home-monitoring devices and found that about 20 percent yielded measurements that were inaccurate by at least 4 mm Hg. "Five mm Hg, over or under, will affect treatment," Goalen noted.
So, with a blood pressure of 120 over 80, although there is actually nothing wrong with you at the moment (or at least there wasn't a week ago) ANC 7 recommends lifestyle changes in the event that you may, at some time in the future develop hypertension. Once again it would seem that a simplistic intervention to improve public health is at best ill conceived and at worst will heighten anxiety among the very people it claims to be protecting.
27 May 2003