March 6, 2020

expert reaction to study looking at low blood pressure and mortality in older adults

Research, published in, reports that low blood pressure is linked to higher mortality in older adults.

Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, said:

“This large-scale observational study adds to the evidence that high blood pressure increases the risk of heart attack, stroke and heart failure in the elderly, regardless of frailty. However, the magnitude of the effect is much smaller than the risk factor of increasing age itself, which is already known.

“The finding that all-cause mortality is barely related to increased blood pressure is new, but as the authors state, it is likely to be due to increasing co-morbidities in the elderly whose effects on mortality outweigh those of blood pressure.

“Previous clinical trials provide robust evidence that lowering blood pressure in the elderly does reduce the risk of developing heart and circulatory diseases, regardless of the degree of frailty. As a result, we strongly advise that elderly people taking medication to lower blood pressure should continue to do so as prescribed.”

Dr Richard Francis, Head of Research, the Stroke Association, said:

“We know that high blood pressure is the biggest cause of stroke and these latest findings don’t change this. However, they do highlight the need for more evidence into the link between blood pressure and stroke in older adults who may have multiple health problems. Although stroke can strike at any age, the risk does increase as you get older. As people are living longer, they will need more support and studies like this could change how we help them to manage their blood pressure. If you’re concerned about your risk of stroke contact your GP or if you would like more information visit stroke.org.uk”

Dr Kazem Rahimi, Deputy Director, The George Institute; Associate Professor of Cardiovascular Medicine & James Martin Senior Fellow in Essential Healthcare, University of Oxford, said:

“The paper is problematic from several point of view. The key issue is that by design, the investigators included all patients irrespective of their health status at baseline. This all-comer design in an observational study is highly prone to bias and limits the interpretation of the results to a simple association (i.e., older people with low blood pressure are at greater risk of death but this observation could simply be an indication they are also much sicker than those who have higher blood pressure; indeed, they might benefit as much or even more from further blood pressure lowering treatment than healthier individuals). Therefore, I do not see how this study could challenge the international guideline recommendations that are largely based on unbiased evidence from randomised clinical trials.

“The authors are right in pointing out that randomised evidence in frail elderly people is limited but unfortunately this paper does not provide any novel or compelling answers to this question. Indeed, putting the issue of uncontrolled confounding aside, I did not see any statistical tests that suggest that associations differed by frailty status. To put this in context, we have at least two randomised trials of blood pressure lowering treatment in elderly which have shown no evidence for a differential effect of blood pressure lowering treatment by frailty status.

“Overall, I do not see how the findings from this study could lead to the conclusion that more personalised blood pressure management is needed. In my view, we should be very careful with such statements as they could lead to unwarranted variation in practice or low adherence rates against guideline recommendation. There is one point that I fully agree with the authors and the press release: We do need more research in this underrepresented population group and until then the best guidance for decision support should be based on careful assessment of all existing evidence, as summarised by international guideline committees.”

Prof Peter Sever, Professor of Clinical Pharmacology & Therapeutics, Imperial College London, said:

“The paper by Masoli and colleagues highlights the discrepancy between clinical trial outcomes for elderly people with high blood pressure and observational studies. The former generally demonstrate that better blood pressure control is associated with better cardiovascular outcomes including mortality, in contrast with the latter where lower blood pressures seem to be associated with higher cardiovascular risk including mortality.

“The SPRINT Trial is often quoted as evidence to support more aggressive blood pressure lowering in elderly people with high blood pressure. This trial reported, in largely non-frail older adults, that blood pressure reduction to <120 mmHg systolic reduced mortality and cardiovascular events compared with a target of <140 mmHg. In this trial, blood pressures were recorded in the absence of attendant physicians or other trial staff and values obtained were probably equivalent to usual recordings 10-15 mmHg higher. Nevertheless, there was no indication of a “J” shaped relationship in this study. Lower pressures were, however, associated with an increase in cases of poor kidney function and fainting due to low blood pressure.

“Observational studies, as exemplified by the current report by Masoli et al., include older patients with varying degrees of frailty in whom lower pressures were clearly linked to adverse cardiovascular outcomes. Patients with moderate or severe indicators of frailty were more likely to be smokers or ex-smokers, have a history of cardiovascular disease (myocardial infarction, stroke or heart failure) or dementia. Such patients are rarely, if ever, recruited into clinical trials.

“Whilst clinical trials remain the gold standard for evaluating the effects of treatment in various patient groups, the results of these trials should be viewed with caution when extrapolating to patients unrepresentative of those recruited into the trials. Based on the Masoli paper, the take home message for practitioners is that the biological age of the patient, incorporating his or her general and cardiovascular health, should determine whether or not tighter blood pressure control (<140mmHg) should be attempted. For the frail, including those with previous stroke, coronary heart disease or dementia, higher blood pressures may be more acceptable (140-160 mmHg systolic) and in all patients, careful evaluation of drug use and potential side effects should be undertaken.” 

Prof David Paterson, President-Elect of The Physiological Society and Professor of Physiology, University of Oxford, said:

“This is a large scale observational study, which has made an important association between blood pressure and mortality in frail elderly adults, and challenges the accepted dogma of what is ‘normal’ when treating blood pressure. 

“If a cause and effect relationship is established between poor cardiovascular outcomes and what is currently considered normal blood pressure in this population, then guidelines will need to be re-thought.

“Importantly, basic physiological research needs to establish if autoregulation of blood flow to essential organs like the heart, brain and kidney is shifted in the elderly, since the body has a built in control system to keep blood flow constant to these areas over a range of perfusion pressures.  Low blood pressure is as dangerous as high pressure, and it is becoming clear what is normal may be age dependent.’  

‘Blood pressure in frail older adults: associations with cardiovascular outcomes and all-cause mortality’ by Masoli et al. was published in Age and Ageing at 00:05 UK time on Friday 6^th March.

DOI: 10.1093/ageing/afaa028

Declared interests

Dr Richard Francis: “No conflicts of interest to declare.”

Dr Kazem Rahimi: “We have several ongoing projects that aim to investigate the question of blood pressure management in older and multimorbid patients.”

Prof David Paterson: No conflict of interest.

Prof Peter Sever: “I have no conflicts of interest.”

None others received.