BY LIZETTE BORRELI
Intensively lowering blood pressure was associated with a reduced risk of developing mild cognitive impairment (MCI) in older adults with hypertension, according to a multi-center randomized clinical trial published online on January 28 in The Journal of the American Medical Association (JAMA).
The Systolic Blood Pressure Intervention Trial Memory and Cognition in Decreased Hypertension (SPRINT MIND) trial found a blood pressure target of 120 mmHg, compared to the standard blood pressure goal of 140 mmHg, lowered the risk for MCI by 19 percent and probable dementia by 17 percent; the reduced risk for probable dementia was not statistically significant, however. The results were first presented at the Alzheimer's Association International Conference in 2018 and were reported by Neurology Today.
SPRINT-MIND, a sub study of the Systolic Blood Pressure Intervention Trial (SPRINT)—designed to test the effect of intensively lowering blood pressure on the heart, kidney, and brain over five years—failed to meet its primary endpoint: reducing dementia incidence. The researchers suggest the success of SPRINT, which led to the trial's early termination at 3.3 years in 2015, cut the study duration too short to accurately assess whether consistently lowering blood pressure would reduce dementia risk.
"Because of early study termination and fewer than expected cases of dementia, the study may have been underpowered for this end point," the researchers, led by Jeff D. Williamson, MD, of Wake Forest University, Winston-Salem, North Carolina, wrote.
To find out whether intensive treatment is associated with reduced dementia risk, the Alzheimer's Association announced it would fund two more years of the study in SPRINT-MIND 2.0.
In the SPRINT-MIND trial, the team followed 9,361 healthy participants with systolic blood pressure (SBP) between 130 and 180 mmHg, both treated and untreated, who were at increased risk for cardiovascular disease for seven years. The average age was 68 years; about 30 percent were black, and 10 percent were Hispanic. About a third had a SBP of 132 mmHg or less; a third had SBP 132–145 mmHg; and the rest had a SBP greater than 145 mmHg.
Researchers randomly assigned participants to either undergo intensive lowering of SBP (goal, <120 mmHg) or standard treatment (goal, <140 mmHg).
Participants received antihypertensive medications from physicians to achieve their assigned blood pressure target. The study did not mandate the use of any specific drug. Most drugs used were generic.
The findings revealed trial interventions did help to successfully control blood pressure with a significant difference between the two treatment groups. The intensive blood pressure group had a mean SBP of 121.6 mm Hg, compared to 134.8 mmHg in the standard group.
During follow-up, participants in the intensive treatment group experienced more significant reductions in MCI risk p (14.6 vs 18.3 per 1000 person-years; hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.69 - 0.95) and the risk for combined cognitive impairment outcome (20.2 vs 24.1 cases per 1000 person-years; HR, 0.85; 95% CI, 0.74 - 0.97).
It remains unknown whether a reduction in MCI risk will lead to a reduction in the risk of progression of dementia.
The National Institutes of Health funded the SPRINT trial with the support of the Department of Veterans Affairs, the Kulynych Family Foundation, and the Oristano Family Foundation. Takeda Pharmaceuticals International provided medications for the study.
Dr. Williamson and his colleagues disclosed relevant relationships with Biogen, Lilly, Sanofi Pharmaceuticals, Novartis Pharmaceuticals, Takeda Pharmaceuticals, Actelion Clinical Research Inc, Boehringer Ingelheim/Lilly, Lundbeck, Novo Nordisk, 98point6, George Clinical Pty, Idorsia Pharmaceuticals, Pfizer, and ROX Medica.
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Williamson JD, Pajewski NM, Auchus AP et al. Effect of intensive vs standard blood pressure control on probable dementia: a randomized clinical trial. JAMA 2019. Epub 2019 Jan 28.