麻豆传媒

CHICAGO -- Intensive blood pressure control in older adults helped reduce risk for mild cognitive impairment (MCI), according a substudy from the controversial SPRINT trial.

Among participants in SPRINT (Systolic Blood Pressure Intervention Trial), a blood pressure (BP) target of <120 mmHg was tied to a significantly lower risk for developing MCI (HR 0.81, 95% CI 0.70-0.95, P=0.01), reported Jeff Williamson, MD, MHS, of Wake Forest School of Medicine in Winston-Salem, North Carolina, and colleagues at the Alzheimer's Association International Conference (AAIC).

Also presented at AAIC were imaging results from some participants in the planned neurocognitive substudy, dubbed SPRINT Mind.

The main SPRINT study had examined whether tight blood pressure targets -- 120 mm Hg or less for systolic pressure -- would reduce the risk of cardiovascular events in individuals with systolic pressure of 130 mm Hg or greater plus one other risk factor. It did, but questions were raised afterward about how blood pressure was measured, with some critics casting doubt on whether any of the results were reliable.

'Change Clinical Practice'

Nevertheless, SPRINT Mind investigators and others at AAIC seemed untroubled by those concerns.

"Patients with any additional risk for CVD [cardiovascular disease] should make sure that their [systolic] BP is controlled to a level in the 120-130 mm Hg range," Williamson told 麻豆传媒. "This is not only good for their heart but also their brain."

Among secondary results in SPRINT Mind, the researchers found a trend towards a lowered risk in probable dementia (HR 0.83, 95% CI 0.67-1.04, P=0.10). However, the combined outcome for MCI and dementia was significantly lower for those with intensive BP control compared with those achieving the standard BP target of <140 mmHg (HR 0.85, 95% CI 0.74-0.97, P=0.02).

"There's nothing that is benign about mild cognitive impairment. It's the first sign of overt cognitive dysfunction, and although the rate at which mild cognitive impairment progresses to dementia may be slow, the appearance of overt cognitive impairment is just as important as the severe dementia," commented AAIC briefing moderator David Knopman, MD, of the Alzheimer's Association Medical & Scientific Advisory Council.

"To be able to see an effect that early in only 2.5 years is actually quite remarkable, really. This is something, frankly, that I think is going to change clinical practice -- not for me as a neurologist, but for people in primary care. And the benefits at the population level... are going to be substantial," added Knopman, who is at the Mayo Clinic in Rochester, Minnesota.

The analysis included 9,361 individuals, ages ≥age 50, whose baseline treated or untreated BP ranged from 130 to 180. All participants also had at least one additional cardiovascular risk factor -- clinical or subclinical CVD, chronic kidney disease, or a Framingham risk score for a cardiovascular event >15% over 10 years. The cohort was ethnically diverse, with around 30% of African-American and 10% Hispanic participants.

Anti-hypertensive medications were administered to participants to help achieve their assigned BP target, and over 90% of prescriptions given during the trial were generic. The investigators collected data on neurocognitive outcomes as well as cardiovascular events.

SPRINT Mind MRI

SPRINT Mind MRI -- the imaging sub-substudy -- found significant imaging evidence of structural brain changes tied to BP control, reported Ilya Nasrallah, MD, PhD, University of Pennsylvania in Philadelphia and colleagues.

Specifically, individuals who had intensive systolic BP control, again a target of <120 mm Hg, had significantly less of increase in cerebral white matter lesion (WML) volume compared with those at the standard target of <140 mm Hg (mean difference 0.64 cm³, P=0.004):

• <120 mmHg target group: 0.28 cm³ (95% CI -0.03 to 0.58) WML volume increase
• <140 mmHg target group: 0.92 cm³ (95% CI 0.59-1.24) WML volume increase

However, both blood pressure target groups showed similar degrees of decreases in total brain volume (TBV) for a mean difference of 2.54 cm³ (P=0.16):

• <120 mmHg target group: 27.3 cm3 (95% CI 24.8-29.8) TBV decrease
• <140 mmHg target group: 24.8 cm3 (95% CI 22.0-27.5) TBV decrease

The MRI subanalysis included 673 participants from the larger SPRINT trial, 454 of whom completed follow-up brain MRIs nearly 4 years after randomization.

Calling the findings "pretty significant," Heather Snyder, PhD, senior director of medical and scientific operations for the Alzheimer's Association, told 麻豆传媒 this is "underscoring that this aggressive treatment [of blood pressure] is also affecting the biology. We're also decreasing the number of white matter lesions.... It benefits brain health in terms of cognition, but you also see that confirmed on the biology with MRI."