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Low daytime BP linked to cognitive decline in older adults with dementia, cognitive impairment

In a study of older adults with dementia and mild cognitive impairment, low daytime systolic BP was associated with cognitive decline in those treated with antihypertensive drugs.

Researchers performed a cohort study of 172 patients from two outpatient memory clinics with dementia and mild cognitive impairment (mean age, 79 years; mean Mini-Mental State Examination score, 22.1). Sixty-eight percent had dementia, 32% had mild cognitive impairment and 69.8% were being treated with antihypertensive drugs.

The primary outcome was cognitive decline, defined as a Mini-Mental State Examination score change between baseline and follow-up. Median follow-up was 9 months.

Lowest BP tertile had greatest change

Patients were stratified into tertiles for daytime systolic BP: 128 mm Hg or lower, 129 mm Hg to 144 mm Hg, and at least 150 mm Hg. Patients in the 128 mm Hg or lower daytime systolic BP tertile had a greater mean change in Mini-Mental State Examination score (–2.8) compared with those in the 129 mm Hg to 144 mm Hg tertile (–0.7; P = .002) and the 150 mm Hg or more tertile (–0.7; P = .003). Results were consistent between those with dementia and those with mild cognitive impairment.

However, this association was significant only among those taking antihypertensive drugs. Treatment with antihypertensive drugs was independently associated with greater cognitive decline for daytime systolic BP (P = .003). Among patients taking antihypertensive drugs, mean Mini-Mental State Examination score change was –3.9 for the lowest tertile, –0.7 for the middle tertile and –0.4 for the highest tertile (P < .001 for lowest vs. middle and lowest vs. highest), whereas among those not taking hypertensive drugs, mean score change was –0.4 for the lowest tertile, –0.8 for the middle tertile and –1.4 for the highest tertile.

The association between office systolic BP and change in Mini-Mental State Examination score was weaker, and there was no association between other ambulatory BP monitoring variables and change in Mini-Mental State Examination score, according to the researchers.

Adverse clinical events not affected

There were no significant differences between the groups in adverse clinical events, including death, major adverse CV events, falling, syncope and hospitalization.

“Because lower [BP] has been associated with brain atrophy in old age, low [systolic BP] may be a marker of a more severe neurodegenerative process,” Enrico Mossello, MD, PhD, from the division of geriatric cardiology and medicine of the department of medicine and geriatrics at Azienda Ospedaliero Universitaria Careggi and University of Florence, Italy, and colleagues wrote. “The present study adds information about older outpatients with [mild cognitive impairment] and dementia, suggesting that strict control of [systolic BP] may negatively affect cognition, with daytime [systolic BPs] of 130 to 145 mm Hg being the most appropriate therapeutic targets. Longitudinal [ambulatory BP monitoring] studies of larger samples with longer follow-up periods are needed to fully evaluate the long-term prognostic effects of [BP] in older adults with cognitive impairment.” – by Erik Swain

Disclosure: The researchers report no relevant financial disclosures.