When low blood pressure is too low in old age

Sven Streit is a general practitioner at the Institute of Primary Health Care (BIHAM) in Bern (CH) and PhD Candidate at Leiden University Medical Center (NL). In this blog, he introduces the results of his PhD in a recent Age & Ageing paper on blood pressure, mortality risk and cognitive decline in a population-based cohort of oldest-old (all 85 years) in Leiden. He tweets @Sven_Streit

With increasing age, blood pressure rises as a consequence of arterial stiffness. It has been debated whether or not to it is beneficial to treat hypertension in old age, especially in >75-year-olds when they have multimorbidity, polypharmacy or frailty. Large hypertension trials showed that lowering blood pressure in over 60-year-olds is beneficial and lowers the risk for myocardial infarction, stroke and all-cause mortality, even in >80-year-olds. However, these trials lack generalizability and typically excluded patients with multimorbidity and frailty. At the same time, observational studies raise concerns about lowering blood pressure too much, since there are several cohort studies showing a reverse association between low blood pressure and increased mortality and accelerated cognitive decline starting from age >75-year-olds. However, current international hypertension guidelines advise physicians to lower blood pressure to values of even <130mmHg in all patients from the age of 60 years, which fuelled discussions about the benefits and harms of lowering blood pressure too much in older patients, especially when they are frail.

We analysed data from the Leiden 85-plus Study, a population-based prospective cohort study of almost all 599 inhabitants of Leiden ageing 85 years and observed them for 5 years. We found that low blood pressure was associated with increased all-cause mortality and accelerated annual cognitive decline in those under antihypertensive treatment. Frailty, measured by low hand grip strength, modified this association for cognitive function; only in those with a weak hand grip strength was there an accelerated cognitive decline. In participants not treated for hypertension, we found no relationship between blood pressure and mortality/cognitive function.

Since we showed that a higher blood pressure has better outcomes, especially in frail 85-year-olds under antihypertensive treatment, this encourages physicians to take an individualized approach and aim for higher blood pressure target levels in these patients. However, future trials are needed that will assess the long-term effect and safety of deprescribing antihypertensive medication in those frail and oldest-old patients that for a long time have been excluded from trials.

Read the Age and Ageing: Lower blood pressure during antihypertensive treatment is associated with higher all-cause mortality and accelerated cognitive decline in the oldest-old—data from the Leiden 85-plus Study 

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