hypertension: lower target is better

A recent retrospective analysis predicted superior clinical outcomes using the new and lower blood pressure guidelines in patients > 60 years old (see htn new guidelines better htn2019 in dropbox, or DOI: 10.1161/HYPERTENSIONAHA.118.12291)

Details:

-- the study compared the predictive value of the 2017 American College Of Cardiology/American Heart Association (ACC/AHA) guidelines vs the 2017 American College of Physician/American Academy of Family Positions (ACP/AAFP) guidelines for people >60yo

    -- ACC/AHA guidelines (the more aggressive ones): begin blood pressure meds if SBP >140 mmHg or DBP >90 mmHg. Also, initiate meds if SBP 130 to 139 or DBP 80 to 89 in those at high cardiovascular risk (history of vascular disease, 10 year ASCVD risk >10%, diabetes, CKD, age >65 with SBP >130 mmHg. Treatment intensification is recommended to get a SBP <130 mmHg; also for a target DBP <80 mmHg in those <65 years old or with high CVD risk. see reference at the end for the blog on this recommendation

    -- ACP/AAFP guidelines (the more lenient ones): begin blood pressure meds in those >60yo with systolic pressure >150 mmHg to target of <150mmHg, or target of 140 mmHg in those with history of stroke/TIA (though, in the text of the article they also include "most" patients with diabetes, vascular disease, metabolic syndrome, CKD, or for "older" adults). and, intensify therapy to achieve a goal of 140 mmHg in those already on meds and at high cardiovascular risk. see htn guidelines older 60 acp aim2017 in dropbox, or doi:10.7326/M16-1785

-- databases:

    -- REGARDS study, designed to look at the cause of the higher rate of stroke mortality among black vs white patients: compared 30,239 white and black patients from the southeastern US to other regions, relevant data available for 10,616 patients

    -- Jackson Heart Study, a population-based prospective cohort study designed to examine the cause of CVD and related risk factors among black patients: 5306 black adults were recruited from Jackson Mississippi between 2000-2004, relevant data available for 1066 patients

-- in those not on antihypertensive meds (baseline characteristics):

    -- antihypertensives recommended by neither guideline (11% of the population):

        -- age 63, 30% male, 36% black, 8% less than high school education, 5% current smoker, BMI 28.5, total cholesterol 210/HDL 59, microalbuminuria 0%, CKD 0%, diabetes 0%, history of CVD 0%, 10 year ASCVD risk 6.4%, blood pressure 125/81

    -- antihypertensives recommended only by the ACC/AHA guidelines (61% of the population had discordant recommendations):

        -- age 70, 59% male, 36% black, 14% less than high school education, 13% current smoker, BMI 28, total cholesterol 197/HDL 52, microalbuminuria 14%, CKD 9%, diabetes 14%, history of CVD 18%, 10 year ASCVD risk 18.7%, blood pressure 132/79

    -- antihypertensives recommended by both guidelines (27% of the population):

        -- age 71, 53% male, 43% black, 21% less than high school education, 16% current smoker, BMI 29, total cholesterol 201/HDL 50, microalbuminuria 25%, CKD 12%, diabetes 24%, history CVD 28%, 10 year ASCVD risk 26%, blood pressure 154/84

--in those already on antihypertensives (baseline characteristics):

    -- for those recommended by only the ACC/AHA guidelines (58% of the population with discordant recommendations)

        -- age 69, 45% male, 54% black, 17% less than high school education, 10% current smoker, BMI 31, total cholesterol 189/HDL 52, microalbuminuria 18%, CKD 17%, diabetes 4%, history CVD 30%, 10 year ASCVD risk 21%, blood pressure 133/79

    -- for those recommended by both guidelines (42% of the population)

        -- age 70, 45% male, 60% black, 25% less than high school education, 12% current smoker, BMI 31, total cholesterol 191/HDL 50, microalbuminuria 33%, CKD 24%, diabetes 3%, history CVD 48%, 10 year ASCVD risk 31%, blood pressure 154/83

-- median follow-up: 12.2 years

    -- in those not on BP meds, total of 592 ASCVD events and 1075 deaths

    -- those already on BP meds, total of 1258 ASCVD events and 2194 deaths

-- they assessed the % of patients in whom initiation or intensification of BP meds would be recommended by these 2 guidelines; with primary outcome of rates of ASCVD events (stroke or coronary heart disease) during follow-up, as well as all-cause mortality among these patients

Results:

-- for patients not taking antihypertensives:

   -- ASCVD events (vs those not recommended by either guideline):

        --those recommended meds by the more aggressive ACC/AHA guidelines only: 5.00 times more likely to have an event (2.94-8.52)

        -- those recommended meds by both guidelines: 6.95 times more likely to have an ASCVD event (4.05-11.91)

    -- all-cause death (vs those not recommended by either guideline):

        -- those recommended meds by the more aggressive ACC/AHA guidelines only: 5.62 times more likely to die (3.71-8.52)

        -- those recommended meds by both guidelines: 8.58 times more likely to die (5.64-13.07)

    -- all of these associations remained statistically significant after multivariate adjustment, including age, sex, race, smoking, diabetes, CKD, BMI, microalbuminuria, total cholesterol, HDL, history of ASCVD)

-- for patients already taking antihypertensives: 

   -- ASCVD events (vs those not recommended by either guideline):

        --those recommended intensification of meds by both guidelines: 72% more likely to have an event (1.54-1.92)

    -- all-cause death (vs those not recommended by either guideline):

        --those recommended intensification of meds by both guidelines: 81% more likely to die (1.67- 1.97)

    -- all of these associations remained statistically significant after multivariate adjustment, as above

Commentary:

-- one concern about the more aggressive ACC/AHA guidelines is that many more people (46% of the population, vs the current 32% !!!!!) will be diagnosed with hypertension, leading to medicalization, anxiety, and more people on meds with their attendant potential complications (for those over 60yo, it is more like 75% of the population by the more aggressive guidelines, vs about 65%). And, as noted above, the largest groups of patients who would be treated were those who met criteria only by the more aggressive ACC/AHA guidelines (61% of the people were in this discordant group).

-- it is quite shocking that there was a 5-fold increase in important clinical cardiovasc events in those who would be treated by these more aggressive ACC/AHA guidelines only, as compared to those not treated at all per the ACP/AAFP guidelines!!

-- but in comparing those treated by just the aggressive guidelines vs being treated by both, there was a remarkably small difference in clinical outcomes

    -- This is pretty striking: there was a hazard ratio of 5.00 comparing those recommended to be treated by only the ACC/AHA guidelines vs those not by either guideline, yet an HR of 6.95 for those recommended to be treated by both guidelines, despite the fact that the actual BP difference between these groups was a lot: 132/79 vs 154/84.  ie, the attributable clinical cardiac risk seems to be greatest going from no hypertension (by either guideline) to the intermediate one of recommended treatment only by the aggressive guidelines. These results suggest 2 things:

    -- it is pretty apparent by the baseline data that there were bigger difference between the normotensives, an apparently really healthy group (no diabetes, CKD, history of CVD and low 10-yr ASCVD risk), than those who would be treated just by the more aggressive guidelines

    -- and that these more aggressive guidelines seem to do a good job in identifying these quite high risk cardiac patients whose blood pressure is not dramatically below the threshold of the more lenient guidelines (as we know from our clinical practice as well as epidemiologic studies such as Framingham, cardiac risk factors usually coexist in the same patient: it is relatively uncommon to just have one isolated one).

--in the group already on BP meds, they found of a 72% increase in clinical events by criteria of both guidelines vs just the more aggressive ones.  This is not so surprising, given the large difference in baseline characteristics, including the blood pressure (ie, this result does not really add much, other than to reaffirm that the more risk factors, the worse the outcomes).

--this study was a retrospective analysis of 2 prior long-term studies (not a specific intervention trial to compare the guidelines directly), so unable to show definitively that lowering the blood pressure according to the more aggressive guidelines would lead to these clinical results).  it does have the benefit of racial diversity (though only 2 of them). Also, there are limited granular data on patients, including whether or not the patients initiated or intensified BP therapy during the follow-up. and not including data on changes in important lifestyle issues (weight, diet, exercise...)

-- one lingering concern is the effects of aggressive BP treatment on cognitive function (ie, are we lowering the blood pressure too much, so that blood cannot be squeezed by the possibly atherosclerotic cerebral vasculature and nourish the brain)??  This problem was not found in the pretty aggressive SPRINT study, with a new analysis finding that after 5 years, there was a trend to decreased dementia [17% decrease, HR 0.83 (0.67-1.04)] but a significant 19% decrease in mild cognitive impairment, HR 0.81 (0.69-0.95).  see htn SPRINT dec MCI with rx jama2019 in dropbox, https://jamanetwork.com/journals/jama/fullarticle/2723256 , or doi:10.1001/jama.2018.21442)

so, an apparently significant validation of the new guideline recommendation of goal BP <130/80 in those >60yo. 

This article basically found that there are lots of patients who would be treated much more aggressively by the ACC/AHA guidelines, and that this group of patients has a really high risk of cardiac events. Other studies (eg Framingham Study) have found that the attributable cardiovasc risk of hypertension itself is much higher in the setting of other comorbidities. In the above study, those with even small increases of blood pressure (the normotensive group average was 125/81, those treated only by ACC/AHA had 132/79) had many more comorbidities and the 5-fold increased cardiovasc risk: this all is consistent (but not definitive) with the approach of treating hypertension in line with the ACC/AHA guidelines.

But, to me, this does NOT mean that we should jump to start meds, or that we should necessarily intensify meds. a really important issue not mentioned in this study (but actually emphasized in the more aggressive ACC/AHA guidelines) is that the foundation of hypertension treatment is lifestyle changes (weight loss if indicated, diet, exercise, sodium, alcohol, NSAIDs, stress ...). lowering the threshold for "hypertension" actually recruits lots more patients as hypertensive and a larger number who are even more likely to achieve normotension through sustained nonpharmacologic therapy.  And even if they remain hypertensive and do get drugs, this lifestyle focus should still provide a myriad of other benefits (eg decreased cancer, dementia, diabetes, etc.  seehttps://gmodestmedblogs.blogspot.com/2019/01/exercise-new-evolutionary-model.html  just for some of them related to exercise).  ie, both patients in general and us clinicians should not feel complacent with just getting  more people on meds, and should use these more aggressive guidelines as a basis to reinforce healthier lifestyles ...

prior related blogs:

http://gmodestmedblogs.blogspot.com/2017/11/new-aha-hypertension-guidelines.html for a more detailied review of the more aggressive 2017 ACC/AHA guidelines
http://gmodestmedblogs.blogspot.com/2018/01/decreasing-blood-pressure-in-elderly.html for a large study finding that the natural history of hypertension is that blood pressure decreases over time in the elderly
http://gmodestmedblogs.blogspot.com/2016/05/sprint-trial-elderly-subgroup-study-of.html/ for a review of the elderly subgroup of patients in the SPRINT trial, reinforcing a lower BP goal in those >75yo

geoff

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