Increasing Time Between BP Screenings: Not Such a Dynamite Idea

Most folks being treated for hypertension are quite familiar with routine BP measurement because their doctor measures and discusses their blood pressure data with them at almost every visit. Many patients will even monitor their own BP at home on a regular basis. Shucks, even people with completely normal BP (<120mmHg systolic, <70mmHg diastolic) are never surprised when a nurse slaps a BP cuff on their arm anytime they visit a doctor's office. Taking BP has simply become 'par for the course' during most any clinical office visit for just about everyone.

But a recent study published in the September 2012 edition of the Journal of Human Hypertension challenges the notion that BP should be measured during each office visit. In "Blood pressure re-screening for healthy adults: what is the best measure and interval?", Takahashi et al acknowledge that BP screening is important, but noted the lack of research done to determine the optimal interval for screening blood pressure in healthy adults. The authors concluded that the optimal BP measurement interval should be three years or more for healthy adults with SBP < 130mmHg, and two years for those with SBP ≥ 130mmHg.

"...making the interval between BP measurements longer in order to prevent over-treatment is like using dynamite to make a hole for a pot of daisies."On the surface, changing clinical practice from measuring BP during each office visit to once every three years seems counterintuitive --even if there is currently a lack of specific data on intervals. The authors provide two main reasons for why their research is relevant:

1. Measuring a person's BP is inconvenient and costly.
2. False-positive results can lead to wasteful intervention.

Personally, I think that (1) is kind of bogus because if a person is already in the clinic, the amount of time that it takes to measure BP is negligible. But they may have a point with (2).

If a person who had normal BP one year ago reads pre-hypertensive or hypertensive during an annual physical, the physician may consider a pharmacological intervention based on other risk factors such as family history and diabetes. But what if the high reading is the result of the patient's normal BP variability? The patient could end up taking meds unnecessarily, so wouldn't it be better to use an optimal measurement interval that accounted somewhat for individual BP variability 'noise'? Hmmm.

I'm not a doctor, nor am I a hypertension researcher--I'm just an industry guy. But it seems to me that making the interval between BP measurements longer in order to prevent over-treatment is like using dynamite to make a hole for a pot of daisies. You'll get a hole, but using a shovel or trowel could have prevented lots of collateral damage. There's been significant discussion in research circles about BP variability and overtreatment because the issue is very real. But many researchers have proposed changing the tools being used to assess BP instead of changing methods. The use of 24-hour ABPM is rapidly gaining ground in Europe due to the recent NICE guidelines, and the use of home BP and home telemedicine devices is exploding as well. The argument here is that using a variety of different tools can help screen out the 'noise' caused by individual variability without missing situations that need real treatment.

I'm thinking we should forget the dynamite and try some different tools instead. What do you think?