Low Blood Pressure, Not Hypertension Linked to Increase Mortality in Seniors

Jane Masoli, PhD

While managing blood pressure typically means lowering it in hypertensive patients, new research from a study out of the United Kingdom is shedding light on the dangers of hypotension in older adults—especially in those considered frail.

Results of the study, which included more than 400,000 older adults, suggested a blood pressure under 130/80 mmHg was associated with excess mortality—with increases in risk as high as 62% among some frail patients—and uncovered hypertension was not associated with increased mortality but with decreased mortality in certain subgroups of patients 75 and older.

"Internationally, guidelines are moving towards tight blood pressure targets, but our findings indicate that this may not be appropriate in frail older adults,” said Jane Masoli, PhD, a geriatrician and National Institutes of Health Research Doctoral Research Fellow, in a statement. “We need more research to ascertain whether aggressive blood pressure control is safe in older adults, and then for which patient groups there may be benefit, so we can move towards more personalized blood pressure management in older adults."

To further available research on blood pressure management in older patients and frail older patients, Masoli and a team of colleagues designed a prospective observational analysis to test the association between baseline blood pressure and incident cardiovascular outcomes. With this in mind, investigators pulled data on a cohort of 415,980 individuals more than 75 years old and at least 3 blood pressure measurements in the prior 3 years.

The primary outcome of the study was all-cause mortality and secondary outcomes were incident cardiovascular events, including stroke, myocardial infarction, or cardiac revascularization. Analyses were conducted per age categories, which were classified as 75 to 84 years old and 85 years of age and older. Blood pressure was defined as the median of measurements over 3 years prior to index date and investigators used systolic blood pressure (SBP) of 130-139 mmHg and diastolic blood pressure (DBP) of 80-90 mmHg as reference groups for their analyses.

The mean age of the study population was 79.5 years, but participants' age ranged from 75-109.5 years. Of the 415,980 included, 260,159 were classified as non-frail and the remaining 155,821 were considered frail—137,772 had mild frailty, 17,032 had moderate frailty, and 1017 were severely frail.

Analyses revealed SBPs in the 140-149 mmHg range (non-frail HR mortality 0.95, 0.93—0.98; mild frailty 0.88, 0.85–0.91) and 150-159 mmHg range (non-frail HR 0.94, 0.92–0.97; mild frailty 0.88, 0.85–0.91; moderate to severe frailty HR 0.84, 0.77-0.92) were associated with lower risk of all-cause mortality compared to those with an SBP between 130-139 mmHg. The only patients with excess mortality associated with high SBPs were those in non-frail or mild frailty categories.

Additionally, analyses indicated SBP under 130 mmHg and DBP less than 80 mmHg were consistently associated with excess mortality, regardless of frailty. This association remained apparent even when accounting for blood pressure trajectory later in life.

Masoli and colleagues noted multiple limitations within their study. Limitations included the use of observational data, blood pressure measurements were taken in clinical settings, the frailest patients may not have been represented due to inclusion criteria, and the possibility for missing data points, among others.

This study, “Blood pressure in frail older adults: associations with cardiovascular outcomes and all-cause mortality,” was published in Age and Ageing.