Skepticism about science and medicine

In search of disinterested science

Blood pressure: Official guidelines make no sense

Posted by Henry Bauer on 2017/11/28

These guidelines make no sense because

  1. BP increases normally with age, as known for more than half a century; yet guidelines for what is said to be “normal” and what is called “hypertension” ignore the correlation with age.
  2. The guidelines are not based on pertinent data because the dependence on age is not properly taken into account.

It’s no wonder, then, that the guidelines were changed in one way in 2013 and in the opposite way just four years later.

At the end of 2013, the most authoritative recommendations for managing blood pressure stated that “There is strong evidence to support treating hypertensive persons aged 60 years or older to a BP goal of less than 150/90 mmHg and hypertensive persons 30 through 59 years of age to a diastolic goal of less than 90 mmHg; however, there is insufficient evidence in hypertensive persons younger than 60 years for a systolic goal, or in those younger than 30 years for a diastolic goal, so the panel recommends a BP of less than 140/90 mmHg for those groups based on expert opinion” [emphases added].

Note first that the criterion for describing someone as “hypertensive” is based on insufficient evidence, which has not prevented modern medicine from being quite dogmatic about calling people of any age hypertensive when their BP exceeds what is the common average in healthy 30-40-year-olds, namely about 140/90.

Then note that the goal of ≤150 systolic not as low as what had been recommended dogmatically for the previous three decades or more.

And then contemplate how to value “expert opinion” that is based on insufficient evidence.

In “Don’t take a pill if you’re not ill”  I made a point I’ve not seen elsewhere: population-average numbers for blood sugar, cholesterol, and BP are taken as the desirable upper limits and medication is administered to lower everyone’s numbers to those levels; yet no consideration is given to raising the numbers if they are lower than the average, even as there is evidence that, for example, higher cholesterol is good for older people since it is associated with lower mortality (1, 2). If the population average is more desirable than higher numbers, why aren’t the averages regarded as better than lower numbers as well?

In “Everyone is sick?” I cited the Institute of Medicine finding that measures like (and including) BP are not symptoms of illness even as they are treated as such; discussed further re BP in “‘Hypertension’: An illness that isn’t illness”.

“60 MINUTES on aging — correlations or causes?” cited the finding that mini-strokes in older people were less frequent with higher blood pressure, the very opposite of the official dogma.

So now in 2017 the guidelines call for significantly lower BP than the 2013-14 set, namely “normal (<120/80 mmHg), elevated (120-129/<80 mmHg), stage 1 hypertension (130-139/80-89 mmHg), or stage 2 hypertension(³140/90 mmHg)”; though it is conceded that this is merely a “strong recommendation” based on “moderate-quality evidence” (3).

Defining hypertension as ≥130 makes it likely that some of this “moderate-quality” evidence came from the SPRINT trial, which concluded (4) that “Among patients at high risk for cardiovascular events but without diabetes, targeting a systolic blood pressure of less than 120 mm Hg, as compared with less than 140 mm Hg, resulted in lower rates of fatal and nonfatal major cardiovascular events and death from any cause, although significantly higher rates of some adverse events were observed in the intensive-treatment group” [emphasis added].

There is here a conundrum: How could there be lower rates of “fatal and nonfatal major cardiovascular events” when Table S5 in the Supplementary Appendix reports only 118 “Serious Adverse Events and Conditions of Interest Classified as Possibly or Definitely Related to the Intervention” under standard treatment (to ≤140) by contrast to 220 under the intensive treatment? With the latter confirming “significantly higher rates of some adverse events were observed in the intensive-treatment group”?

At any rate, all these data are incapable of delivering a meaningful answer about possible risks posed by high BP. Since BP increases with age, the only way to detect its possible risk would be to monitor the health and mortality rates of cohorts of people of the same age, and this is not the case in the SPRINT Trial.

There are plenty of other reasons to be wary of the SPRINT study. The Supplementary Appendix asserts that “All components of the SPRINT study protocol were designed and implemented by the investigators. The investigative team collected, analyzed, and interpreted the data. All aspects of manuscript writing and revision were carried out by the coauthors. The content is solely the responsibility of the authors”. But which ones exactly? There are 6 pages of names; there were 102 clinical sites; a trial coordinating center and centers for MRI reading and electrocardiography reading; an independent data and safety monitoring board; institutional review boards at each clinical site; and a steering committee (13 members) and a writing committee (members not detailed in the Appendix).

When everyone is responsible, then in practice no one is responsible.

Rhetorical questions:

Ø      Who conceived the idea of testing more stringent criteria than formerly for controlling BP?

Ø      What data stimulated that idea, given that the 2013 guidelines cited above revealed a lack of evidence for a systolic goal in persons younger than 60?

Ø      Why are there no statements about conflicts of interest? Biomedical research requires funding. Research articles typically list potential conflicts of interest, and it is well known that most biomedical scientists have some sort of consulting or other relationship with drug companies. Here the only possible clue lies in the Acknowledgments: “The SPRINT investigators acknowledge the contribution of study medications (azilsartan and azilsartan combined with chlorthalidone) from Takeda Pharmaceuticals International, Inc.”

The official BP guidelines make no sense because

  1. BP increases normally with age, as known for more than half a century; yet guidelines for what is said to be “normal” ignore the correlation with age.
  2. The guidelines are not based on pertinent data but on admittedly “moderate-quality” evidence; that is actually of much lower quality than that because it does not offer age-specific information.

**************************************************************************

  1. Schatz et al., “Cholesterol and all-cause mortality in elderly people from the Honolulu Heart Program: a cohort study”, Lancet, 358 (2001) 351-5.
  2. Chapter 3 in Joel M. Kaufmann, Malignant Medical Myths, Infinity Publishing, 2006; ISBN 0-7414-2909-8.
  3. Adam S. Cifu & Andrew M. Davis, “JAMA Clinical Guidelines Synopsis: Prevention, detection, evaluation, and management of high blood pressure in adults”, JAMA; published online 20 November 2017; Clinical Review & Education, E1-3.
  4. The SPRINT Research Group, “A randomized trial of intensive versus standard blood-pressure control”, New England Journal of Medicine, 373 (2015) 2103-16.

 

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