Decreasing blood pressure in elderly

one pretty common phenomenon in my very elderly is that their blood pressure seems to decrease as they age, leading to my down-titrating their antihypertensives and occasionally stopping them. prior studies regarding this phenomenon have produced mixed results, some suggesting this is just a near-terminal event. But, a recent large long term study pretty conclusively validated this observation as being “normal” (see Delgado J. JAMA Intern Med. 2018;178(1):93-99).

Details:

--46,634 participants >60yo from 674 primary care practices in the UK who had died from 2010 to 2014 and had been followed at least 20 years prior to death. All had been tracked in the population-based Clinical Practice Research Datalink, which linked primary care and  hospitalization electronic medical records

--51.7% female; mean age at death was 82.4 years​ (women were 45.5% of those dying age 60-69, but 64.6% of those at least 90yo).

--pretty healthy cohort: comorbidity and frailty indices skewed somewhat to lowest degree (eg, in those >90yo, 35% had lowest score on Rockwood Frailty Index and 24% had the least comorbidity by Charlson Comorbidity Index)

--BP slopes were evaluated from 10 to 3 years before death for 20,207 participants who died, plus 20 207 birth-year and sex-matched participants surviving longer than 9 years.

Results:

--in the 20 years prior to death, BP trajectory (the diastolic pressures mirrored the systolic ones):

    --60-69 yo: systolic increased for 6 years to a max of about 146 mmHg, then decreased the next 14 years to about 135 mmHg (10.6/9.0 mmHg)

    ​--70-79 yo: systolic increased for 5-6 years to a max of about 146 mmHg, then decreased the next 14-15 years to about 130 mmHg  (15.4/11.3 mmHg )   

    ​--80-89 yo: systolic increased for 5-6 years to a max of about 150 mmHg, then decreased the next 14-15 years to about 129 mmHg (20.5/12.1 mmHg)

    ​-->90 yo: systolic stable initially with max of about 151 mmHg, then decreased the next 18-20 years to about 127 mmHg (23.9/12.2 mmHg)

--proportion of sample with decrease in SBP from peak to year of death:

    ​--60-69: 48% had >10 mmHg change; 32% >20mmHg change, and 17% had >30mmHg change

    --overall: 64% had >10 mmHg decrease in their SBP

--the mean systolic blood pressure trajectories were very similar in the different age groups independent of several underlying medical conditions (hypertension, atrial fibrillation, heart failure, cancer) or the composite Charlson comorbidity index; though there were increased differences over time in those:

    --who were more frail, where the curve to decreasing blood pressure deviated progressively from the non-frail about 14 years prior to death, with an ultimate difference of about 10 mmHg

    --with treated hypertension (85% had treatment for at least 1 year), there was a 20.8 mmHg SBP fall from the peak to the time of death; for those nonhypertensive, there was a 11.2 mmHg fall

    --though those with >20 kg weight loss (between the first 10 years til the final year of life), there was more SBP fall (24.9 vs 15.9 mmHg)

    --but smoking, alcohol, and level of physical activity measured 20 years prior to death had little relationship with SBP decreases

--in a separate analysis assessing the decreases in SBP from 10 to 3 years before death: the SBP trajectories were linear (did increase in last 2 years), though were greater in those with hypertension, heart failure, atrial fibrillation, dementia, CKD, COPD, or stroke/TIA diagnosed any time prior to death

--and, comparing cases of those who died vs those surviving at least 9 more years, per 10-year age grouping,  decreases in BP were more marked in those who died, controlling by  birth-year- and sex-matched surviving participants.​

Commentary:

--this study documented pretty dramatic decreases in blood pressure in older people, as a pretty normal phenomenon (ie, undercutting prior concerns that the lower blood pressures were just the result of increasing end-of-life diseases such as heart failure or failure-to-thrive), and were validated by the very long trajectories of lower blood pressure until death (ie, noting similar blood pressure trajectories for people within the same age groups whether they died within 3 years or >9 years)

--in general, BP decreases with age after peaking about 14-18 years prior to death, with 64% experiencing at least a 10 mmHg fall in SBP independent of antihypertensive treatment, though the decreases were steepest in people with treated hypertension, dementia, heart failure, and late-life weight loss

so, there are several implications to this study:

--though BP does decrease faster in patients with some medical comorbidites and frailty, 2/3 of patients have at least a 10mmHg falloff in SBP: decreasing BP seems to be a normal finding even in those without comorbidities or frailty

--it is important to track BP in the elderly, especially those with hypertension on meds who have a particularly great decrease in BP. I also think we should be careful to monitor blood pressures appropriately (quiet room, resting several minutes, etc, as per blog: http://gmodestmedblogs.blogspot.com/2017/09/the-most-important-hypertension-blog.html ) and measure postural changes (esp initial orthostatic hypotension, as per blog: http://gmodestmedblogs.blogspot.com/2017/08/initial-orthostatic-hypotension-and.html ), and titrate BP meds down as needed.  this may be particularly important if one adopts the lower target blood pressure suggested by the SPRINT study (see http://gmodestmedblogs.blogspot.com/2016/05/sprint-trial-elderly-subgroup-study-of.html  or the recent AHA guidelines with goal of 130/80 (see http://gmodestmedblogs.blogspot.com/2017/11/new-aha-hypertension-guidelines.html ).

--of note, i have even had a couple of previously hypertensive very elderly patients who ultimately needed a high salt diet and fludrocortisone/midodrine for several years in order to prevent them from becoming symptomatically hypotensive....