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Lower systolic BP in elderly may imply higher mortality rates
Participants aged at least 80 years with a systolic BP lower than 120 mm Hg experienced higher mortality regardless of their treatment for hypertension, frailty status and sex, according to a study in Circulation.
Previous clinical studies have shown that treating older individuals with high BP with antihypertensive medications may reduce CV events and mortality, according to the study background.
“Our results suggest that a substantial decline in [BP] may be a recognizable feature of the final stages of life, at least in the final 2 years, with lower [systolic] BP often being a marker of proximity to death,” Rathi Ravindrarajah, PhD, research associate at King’s College London department of primary care and public health services, and colleagues wrote.
BP and frailty
Researchers analyzed electronic health records from 144,403 participants aged 80 years and older from the United Kingdom from 2001 to 2014. Participants were categorized by systolic BP and frailty level (fit, mild, moderate and severe). Follow-up occurred for up to 5 years.
Of the entire cohort, 3% of participants (n = 4,389) had systolic BP less than 110 mm Hg, and 12.5% (n = 17,983) exhibited systolic BP more than 160 mm Hg. Those with lower BP were more likely to have increasing frailty and diagnoses of CHD, dementia and stroke.
At follow-up, 51,808 participants died, and mortality rates were greatest in participants with a systolic BP less than 110 mm Hg and higher frailty levels. Participants with systolic BP between 140 mm Hg and 159 mm Hg had the lowest levels of mortality among all levels of frailty. Mortality rates in those with systolic BP less than 110 mm Hg were more than tripled compared with those with systolic BP between 140 mm Hg and 159 mm Hg.
Mortality rates in fit women treated with antihypertensive medications were 7.7 per 100 person-years in those with a systolic BP between 120 mm Hg and 139 mm Hg, 15.2 per 100 person-years in participants with a systolic BP between 110 mm Hg and 119 mm Hg and 22.7 per 100 person-years in those with a systolic BP less than 110 mm Hg.
Women with severe frailty who took antihypertensive medications had higher mortality rates than fit women: 16.8 per 100 person-years (120-139 mm Hg), 25.2 per 100 person-years (110-119 mm Hg) and 39.6 per 100 person-years (< 110 mm Hg).
Lower systolic BP
The decline in systolic BP accelerated in the last 12 to 24 months of life. Systolic BP was nearly 15 mm Hg lower at the end of the study compared with baseline. At the last 3 months of life, relative odds of participants with a systolic BP less than 120 mm Hg was higher compared with 5 years prior in patients who took antihypertensive medications (OR = 6.06; 95% CI, 5.4-6.81) and those who were not treated (OR = 6.31; 95% CI, 5.3-7.52).
There was no evidence in the electronic health records that those who died received stronger antihypertensive therapy or whether the therapy was intensified in the final months of life.
“Whether the observation of more favorable outcomes with higher [systolic] BP for periods more than 2 years before death is ‘true’ or confounded remains uncertain,” Ravindrarajah and colleagues wrote. “Consequently, it may be inadvisable to base [BP] treatment recommendations on nonrandomized data for effectiveness outcomes. We noted [systolic] BP values less than 100 mm Hg in a minority of treated patients, which suggests that reducing the intensity of antihypertensive therapy may sometimes be important in this age group.” – by Darlene Dobkowski
Disclosure: The researchers report no relevant financial disclosures.