Study Synopsis & Review Guide: Blood Pressure Control & Dementia

By: Joe Darrah

With this study synopsis and review file, Elite guides readers through the salient points of a recent NIH-funded study that examined the potential of dementia risk to be reduced through clinical control of blood pressure.

Reducing the risk of mild cognitive impairment (MCI) and dementia has not been proven possible through any clinical treatments.1 A recent study funded by the National Institutes of Health (NIH) attempted to learn more about the potential to lessen the chances of dementia through strict blood pressure control — with mixed results that do not appear to be consistent enough to suggest this is possible. The multiyear study — the Systolic Blood Pressure Intervention Trial (SPRINT) Memory and Cognition in Decreased Hypertension (MIND) study — did show, however, that intensive blood pressure lowering significantly reduced the risk of mild cognitive impairment (MCI), a common precursor of Alzheimer’s disease,2 in the participants, although subtle changes in cognition have been said to be difficult to measure without the benefit of time.3 According to the NIH, researchers of the SPRINT MIND study found that lowering blood pressure was a safe practice for the brain. Assessment of the study and its potential impact on treatment for patients living with hypertension has varied.

While most neurodegenerative diseases take many years to develop and thus have a long preclinical phase, this has spurred interest in prevention, writes Kristine Yaffe, MD,4 adding that identification of preclinical or early clinical phases, such as MCI, is critical for these primary and secondary prevention approaches.

As noted by Kenneth W. Lin, MD, MPH, many persons living with MCI do not develop dementia,3 which has led to his questioning whether the study’s noted benefits alone make it worth the increased risks of syncope, severe hypotension, or acute kidney injury. However, Lin also writes that the SPRINT MIND results “may make the benefit-versus-harm assessment more favorable for patients already receiving treatment” [for high blood pressure]. For those providers who are already thinking about aiming for a lower systolic blood pressure goal for cardiovascular prevention with their hypertensive patients, the possibility of additional cognitive benefits might be good enough to sway the decision to treat.3 “While not game-changing, these findings should be discussed with patients at high cardiovascular risk in decision-making about antihypertensive therapy, especially those who place greater value on preserving cognitive function relative to avoiding medication side effects,” Lin also writes.
Preliminary findings from the SPRINT MIND study, a sub-study of the NIH-funded SPRINT trial that aimed to determine whether aggressively lowering blood pressure could protect the heart, kidney, and brain over five years,5 were presented July 25 at the Alzheimer’s Association International Conference in Chicago.

Study Title & Authors: Effect of Intensive Vs. Standard Blood Pressure Control on Probable Dementia: A Randomized Clinical Trial; Systolic Blood Pressure Intervention Trial (SPRINT) Memory and Cognition in Decreased Hypertension (MIND) Investigators for the SPRINT Research Group

Original Source of Publication: Journal of the American Medical Association (https://jamanetwork.com/journals/jama/article-abstract/2723256) – Trial Registration Identifier = ClinicalTrials.gov – NCT01206062

Methodology & Interventions:

A randomized clinical trial that included more than 100 sites in the United States and Puerto Rico. Participants totaled more than 9,300 people — adults ages 50 years and older who were living with hypertension (but without diabetes or history of stroke) at the time of enrollment. Randomization began Nov. 8, 2010, and the final date for follow-up of cognitive outcomes was July 22, 2018. The trial ended early for the benefit on its primary outcome (a composite of cardiovascular events) and all-cause mortality on Aug. 20, 2015.

Participants were randomized to a systolic blood pressure goal of either less than 120 mm Hg (intensive treatment group; n = 4678) or less than 140 mm Hg (standard treatment group; n = 4683).

Derived Data Highlights:

  • Total of 9,361 randomized participants
  • Mean age of participants was 67.9 years
  • The median intervention period was 3.34 years.
  • During a total median follow up of 5.11 years, adjudicated probable dementia occurred in 149 participants in the intensive treatment group versus 176 in the standard treatment group
  • Intensive blood pressure control significantly reduced the risk of mild cognitive impairment (14.6 versus 18.3 cases per 1,000 person-years; and the combined rate of mild cognitive impairment or probable dementia (20.2 versus 24.1 cases per 1,000 person-years).

Analysis Overview: The primary cognitive outcome was an occurrence of adjudicated probable dementia. Secondary cognitive outcomes included adjudicated mild cognitive impairment and a composite outcome of mild cognitive impairment or probable dementia.

Key Outcomes & Results:

  • The primary cognitive outcome was an occurrence of adjudicated probable dementia.
  • Secondary cognitive outcomes included adjudicated mild cognitive impairment and a composite outcome of mild cognitive impairment or probable dementia.
  • Aggressively lowering blood pressure in hypertensive older adults did not significantly reduce dementia risk.
  • Intensive blood pressure control showed statistically significant benefits in secondary outcomes.
  • Among ambulatory adults living with hypertension, treating to a systolic blood pressure goal of less than 120 mm Hg compared with a goal of less than 140 mm Hg did not result in a significant reduction in the risk of probable dementia. (Randomization to a systolic blood pressure target of less than 120 mm Hg compared with less than 140 mm Hg resulted in a rate of probable dementia of 7.2 versus 8.6 cases per 1,000 person-years, a difference that was not statistically significant).
  • Because of early study termination and fewer than expected cases of dementia, the study may have been underpowered for this endpoint.

References

  1. The SPRINT MIND investigators for the SPRINT research group. Effect of intensive vs. standard blood pressure control on probable dementia: a randomized clinical trial. JAMA. 2019;321(6):553-61.
  2. Preventing Alzheimer’s disease: what do we know? NIH. Accessed online: www.nia.nih.gov/health/preventing-alzheimers-disease-what-do-we-know
  3. Lin, KW. A game-changer to prevent cognitive loss? maybe not. Medscape. Accessed online: www.medscape.com/viewarticle/909957
  4. Yaffe K. Prevention of cognitive Impairment with intensive systolic blood pressure control. JAMA. 2019;321(6):548-9.
  5. Systolic Blood Pressure Intervention Trial. Accessed online: www.sprinttrial.org/public/dspHome.cfm

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About The Author

Joe Darrah is a freelance author based in the Philadelphia region who has been covering the healthcare field since 2004. He may be reached at [email protected] Lawrence F. Kobak is senior counsel in the healthcare department at Frier Levitt, a national boutique healthcare law firm based in Uniondale, NY, that provides comprehensive regulatory, transactional, and litigation counsel to the healthcare and life sciences industries. He may be reached at [email protected]