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The American Heart Association and the American College of Cardiology have announced a change in the guidelines for defining blood pressure categories.

In particular, they have lowered the point of treatment from 140/90 mm Hg to 130/80 mm Hg, which means many more Americans will be considered at risk and require management (even if they don't require hypertensive medication.)

Paul K. Whelton, M.B., M.D., M.Sc., lead author of the guidelines published in the American Heart Association journal, Hypertension and the Journal of the American College of Cardiology, noted the dangers of blood pressure levels between 130-139/80-89 mm Hg.

“You’ve already doubled your risk of cardiovascular complications compared to those with a normal level of blood pressure,” he said. “We want to be straight with people – if you already have a doubling of risk, you need to know about it. It doesn’t mean you need medication, but it’s a yellow light that you need to be lowering your blood pressure, mainly with non-drug approaches.”

Is it true that this range of blood pressure is associated with a doubling in risk of cardiovascular complications?

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blacksmith37
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1 Answers1

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I was expecting to find plenty of evidence to support the American Heart Association and the American College of Cardiology. After all:

They were written by a panel of 21 scientists and health experts who reviewed more than 900 published studies.

However, the research I found went in the opposite direction. I am not convinced that it is sufficient to overturn the advice from professionals, but it would be cherry-picking not to report it here.

The most direct evidence is from the Cochrane Library which is a database of high-quality systematic reviews.

This paper looked at the effect of setting different targets in patients to lower their blood pressure. Standard targets were ≤ 140‐160/ 90‐100 mmHg. Lowered targets were ≤ 135/85 mmHg.

While setting a lowered BP target did mean that patients achieved lower BPs, it didn't improve their health on a number of factors:

Seven trials (22,089 subjects) comparing different diastolic BP targets were included. Despite a ‐4/‐3 mmHg greater achieved reduction in systolic/diastolic BP, p< 0.001, attempting to achieve "lower targets" instead of "standard targets" did not change total mortality (RR 0.92, 95% CI 0.86‐1.15), myocardial infarction (RR 0.90, 95% CI 0.74‐1.09), stroke (RR 0.99, 95% CI 0.79‐1.25) , congestive heart failure (RR 0.88, 95% CI 0.59‐1.32), major cardiovascular events (RR 0.94, 95% CI 0.83‐1.07), or end‐stage renal disease (RR 1.01, 95% CI 0.81‐1.27). The net health effect of lower targets cannot be fully assessed due to lack of information regarding all total serious adverse events and withdrawals due to adverse effects in 6 of 7 trials. A sensitivity analysis in diabetic patients and in patients with chronic renal disease also did not show a reduction in any of the mortality and morbidity outcomes with lower targets as compared to standard targets.

Looking at the confidence intervals, it is clear that it might be a little bit helpful, but the available research in 2009 wasn't enough to confirm it. (If further research has been done in the intervening 10 years, it hasn't reached the level of being reported by Cochrane.)

A related study looked at whether giving pills to people with mild hypertension (systolic blood pressure (BP) 140‐159 mmHg and/or diastolic BP 90‐99 mmHg) was worthwhile. (Note the original claim denied that this would be common, so this is a side-claim.)

  • Diao D, Wright JM, Cundiff DK, Gueyffier F. Pharmacotherapy for mild hypertension. Cochrane Database of Systematic Reviews 2012, Issue 8. Art. No.: CD006742. DOI: 10.1002/14651858.CD006742.pub2.

Of 11 RCTs identified 4 were included in this review, with 8,912 participants. Treatment for 4 to 5 years with antihypertensive drugs as compared to placebo did not reduce total mortality (RR 0.85, 95% CI 0.63, 1.15). In 7,080 participants treatment with antihypertensive drugs as compared to placebo did not reduce coronary heart disease (RR 1.12, 95% CI 0.80, 1.57), stroke (RR 0.51, 95% CI 0.24, 1.08), or total cardiovascular events (RR 0.97, 95% CI 0.72, 1.32). Withdrawals due to adverse effects were increased by drug therapy (RR 4.80, 95%CI 4.14, 5.57), Absolute risk increase (ARI) 9%.

The authors called for more research to determine if the benefits outweigh the harms, but it appears in the general case, mild hypertension does not justify the use of antihypertensive drugs.

In conclusion, the Cochrane-reported research (which I generally hold in high-esteem), as of 2009, did not support telling patients to target the lower BP ranges and did not support the prescriptions of tablets for people with mild hypertension.

I would continue to recommend following your doctor's orders and/or getting a second opinion from another appropriately-trained medical professional, rather than some guy on the Internet.

Oddthinking
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    *"I was expecting to find plenty of evidence to support the American Heart Association"*. Not everyone thinks the AHA knows what they're doing, especially with regards to the increasing recommendations of statins for the ever decreasing high blood pressure and cholesterol thresholds. –  Dec 16 '18 at 16:43
  • @fredsbend: I expect they know what they are doing more than I trust my own research skills. But not reporting what I found seemed worse – Oddthinking Dec 16 '18 at 16:45
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    I trust your research skills much more than you do? (And come to the same result, btw) Looking at vitamin and other nutritional advice (cholesterol?) we have to conclude that neither errors, hasty & overly optimistic conclusions nor plain corruption can be excluded and *blind* trust in these organisations is ill founded. Many of these orgs are economically influenced political committees. Those conflicts of interest are *incompatible* with science – LangLаngС Dec 16 '18 at 18:20
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    Less chatty: I'd like to see a more clearly visible yes/no/maybe; a "disclaimer" that this about epidemiological probabilities: interventions carry risks and overall complications or mortalities are often neglected. For the cochrane paper you cited it might be worth to add some qualifications for different combinations of factors (diabetes etc., isolating just BP might be misleading) – LangLаngС Dec 16 '18 at 18:28
  • In case you missed the following: DOI:10.1097/HJH.0000000000001940 2018 ESC/ESH Guidelines for the management of arterial hypertension (2018): **New** "Treatment thresholds: Highnormal BP (130 –139/85–89 mmHg): Unless the necessary evidence is obtained, it is not recommended to initiate antihypertensive drug therapy at high–normal BP." – LangLаngС Dec 16 '18 at 18:36
  • Darnit: Another addition: lower(ie 'normal') BP *is* better, and how to achieve it is the real Q? If you get there with diet, sport and relaxation than the negative outcomes associated with intervention are not really to be expected, but do it with Big Pharma's portfolio and side-effects *will be there* (don't get me wrong there: and apparently 'worth it' given the accumulated risk factors and findings for conditions). That's quite a kicker to clear up here. – LangLаngС Dec 16 '18 at 18:44
  • @LangLangC: re: last comment. I thought I had covered this. The studies suggest setting lower BP as a target does successfully get people to lower their BP, but it doesn't get them healthier (according to a number of measures). Plus medication doesn't help (although the authors are reluctant to draw that conclusion). I am not sure what I need to clear up. Could you elaborate, please? – Oddthinking Dec 17 '18 at 00:33
  • There is a discrepancy between title and quote claim. Depending on age, BP<130 is always desirable (but just an indicator?), 'relative risk' increases (not linearly) with higher BP, but mitigated by age. Key is: "*you*'ve doubled your risk" (just untrue, [despite BP>140 starting to be cause factor itself] and implies the reverse, with no evidence (your main point here)) Doubling low risks has less absolute impact/ a more significant increase (inflection of the curve) when the preceding absolute risks are already high. https://www.ncbi.nlm.nih.gov/pubmed/28122885 10.1016/j.cardfail.2017.02.005 – LangLаngС Dec 17 '18 at 10:43