The Alzheimer’s Association has funded a two-year extension of the SPRINT-MIND study — SPRINT MIND 2.0 — to further explore the role of intensive treatment to lower blood pressure and the risk of dementia.
The funding, which totals more than $800,000, will allow researchers to follow the participants of the original trial for two years, which was inconclusive in its results.
The trial was published in the Journal of the American Medical Association (JAMA) in an article titled, “Effect of Intensive vs Standard Blood Pressure Control on Probable Dementia.”
“SPRINT MIND 2.0 and the work leading up to it offers genuine, concrete hope,” Maria C. Carrillo, PhD, Alzheimer’s Association Chief Science Officer said in a press release. Mild cognitive impairment (MCI) “is a known risk factor for dementia, and everyone who experiences dementia passes through MCI. When you prevent new cases of MCI, you are preventing new cases of dementia.”
The SPRINT MIND study (NCT01206062) was a large-scale, long-term clinical trial that compared two strategies for managing high blood pressure (hypertension) in older adults: intensive treatment to lower systolic blood pressure to under 120 mm Hg, or a standard approach to drop or keep systolic blood pressure to under 140 mm Hg.
Systolic blood pressure (SPB) — the pressure in blood vessels when the heart beats — is considered normal when values are below 120 mm Hg, and high when they vary between 130 and 139 mm Hg.
The study investigated if an intensive treatment approach would also lower the risk of MCI — an intermediate clinical stage that does not yet meet the criteria for dementia — and that of dementia.
The trial enrolled 9,361 adults, 50 years or older (mean age was 67.9, with 35.6% women), with hypertension but without dementia starting in October 2010. Blood pressure treatment was stopped in 2015 after a median intervention of 3.34 years, and an overall median follow-up of 5.11 years. The final date for follow-up was July 22, 2018.
A total of 8,563 (91.5%) participants completed at least one follow-up assessment of cognition.
The results showed that intensive blood pressure treatment lowered the risk of cardiovascular disease. After one year of treatment, those given intensive treatment had a mean systolic blood pressure of 121.4 mmHg, while mean SBP for those in the standard treatment group was 136.2 mmHg.
Moreover, intensive blood pressure treatment was associated with a statistically significant 19% reduction in new cases of MCI and a 17% decrease in a combined outcome of MCI or probable dementia.
The success of the heart disease portion of the study led to early termination of the intensive intervention treatment, which meant that the duration of the trial was probably not enough to assess the impact on dementia.
“Dementia takes longer to develop than MCI. Consequently, the early termination of the study likely affected the number of dementia cases detected,” said Jeff D. Williamson, MD, M.H.S., geriatric medicine specialist at Wake Forest School of Medicine and SPRINT principal investigator.
“Further cognitive assessment of the SPRINT MIND study participants might discover enough additional cases of probable dementia to support a more definitive conclusion,” he added.
By the study’s end, 149 participants in the intensive treatment group were diagnosed with probable dementia compared with 176 participants in the standard treatment group, but this difference was not statistically significant.
“The Alzheimer’s Association finds these data to be compelling, and is committed to getting clarity and certainty on the dementia outcome by following participants for a longer period of time,” Carrillo said.
SPRINT MIND 2.0 is expected to begin in early 2019, making the results available one year earlier than what had been previously estimated, due to the funding from the Alzheimer’s Association.
“The Alzheimer’s Association is committed to getting the answers about treating and preventing Alzheimer’s and other dementias. We are filling the gaps in Alzheimer’s research, and — with the support of our donors and partners — we act rapidly to maximize opportunities,” Carrillo said.
“Proof that lowering blood pressure can lower risk for dementia may be key to improving the lives of millions of people around the world,” she added.