The SPRINT MIND study did find that intensive treatment reduced the risk of mild cognitive impairment, a precursor to dementia.
Jeff D. Williamson, MD, MHS
Lowering blood pressure to a target of 120 mm Hg versus 140 mm Hg did not significantly reduce the risk of dementia in older adults with hypertension, according to the full results of the Systolic Blood Pressure Intervention Trial (SPRINT) Memory and Cognition in Decreased Hypertension (SPRINT MIND), despite promising preliminary results.
The study randomized 9361 participants with a mean age of 67.9 years to either the intensive blood pressure control group (target BP of 120 mm Hg) or the standard treatment group (target BP of 140 mm Hg). The study reported adjudicated probable dementia in 149 participants in the intensive treatment group compared to 176 in the standard treatment group, with a hazard ratio (HR) of .83 (95% CI, .67-1.04).
“Dementia continues to be a large public health challenge, and based on the primary results of this study, we still have yet to find an intervention strategy proven to reduce the risk of dementia,” said Richard J. Hodes, MD, director of the National Institute on Aging (NIA), a part of NIH, in a statement.
SPRINT MIND was an extension of the SPRINT trial that compared the effect of reducing systolic blood pressure below 140 mm Hg or 120 mm Hg on cardiovascular outcomes. Stunning cardiovascular results led researchers to end the study about a year early and contributed to the 2017 American Heart Association (AHA) and American College of Cardiology’s (ACC) guidelines on hypertension.
However, the early study termination and few cases of dementia among participants meant that the SPRINT MIND may have been unempowered for that endpoint, wrote study authors. Nonetheless, the results did report that intensive treatment had a significant effect on mild cognitive impairment (MCI), a precursor to dementia.
MCI, a secondary outcome, occurred in 287 study participants in the intensive treatment group and 353 of those in the standard treatment group (14.6 vs 18.3 per 1000 person-years; HR, .81; 95% CI, .69-.95; P = .007). The composite of MCI or probable dementia measured 20.2 vs. 24.1 cases per 1000 person-years, respectively, with a hazard ratio of .85 (95% CI, .74-.97; P = .01).
“The fact that there was still an MCI result when the study was cut short makes these results encouraging,” explained Laurie Ryan, PhD, chief of the Dementias of Aging Branch in the NIA Division of Neuroscience, in a statement.
Further, the study authors noted that, to their knowledge, this is the first trial that shows an intervention that successfully reduced the risk of MCI. They added, however, that “although MCI considerably increases the risk of progression to dementia, such progression is not certain and reversion to normal cognition is also possible.”
In a JAMA editorial on SPRINT MIND, Kristine Yaffe, MD, characterizes the study as a “major leap forward” in the “marathon journey” of developing prevention strategies for mild cognitive impairment and dementia.
That marathon will continue, as the Alzheimer’s Association announced today that it will fund a 2-year extension of the SPRINT MIND trial. The SPRINT MIND 2.0 Study will continue to study the impact of intensive and standard hypertension treatment on reducing dementia risk.
"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, MHS, Chief of the Section on Geriatric Medicine and Gerontology at Wake Forest School of Medicine and SPRINT principle investigator, in a statement. "Further cognitive assessment of the SPRINT MIND study participants might discover enough additional cases of probable dementia to support a more definitive conclusion."
The study, “Effect of Intensive vs Standard Blood Pressure Control on Probable Dementia: A Randomized Clinical Trial,” was published today in JAMA.