Dementia increases with age. About 50% of the population 85 years or older will experience some degree of cognitive impairment. Obviously, this problem places an enormous burden on those charged with the care of these patients and an economic load on all of society. There is no treatment currently available to retard cognitive decline in the elderly or near elderly. One might imagine that better blood pressure control might have a beneficial effect on this population. That was the reason that the study outlined below was performed. Published in the Journal of the American Medical Association: “Effect of Intensive vs Standard Blood Pressure Control on Probable Dementia – A Randomized Clinical Trial” disappointingly, failed to show any benefit of lowering systolic blood pressure on the development of dementia.
The study was short and thus may have been underpowered to address the question it asked. There are good reasons to control systolic blood pressure, but at least for now preventing dementia is not one of them. The abstract of the JAMA paper is below as is a pictorial depiction of its findings. Clicking on the figure will give a larger image.
Importance There are currently no proven treatments to reduce the risk of mild cognitive impairment and dementia.
Objective To evaluate the effect of intensive blood pressure control on risk of dementia.
Design, Setting, and Participants Randomized clinical trial conducted at 102 sites in the United States and Puerto Rico among adults aged 50 years or older with hypertension but without diabetes or history of stroke. Randomization began on November 8, 2010. The trial was stopped early for benefit on its primary outcome (a composite of cardiovascular events) and all-cause mortality on August 20, 2015. The final date for follow-up of cognitive outcomes was July 22, 2018.
Interventions 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).
Main Outcomes and Measures The primary cognitive outcome was occurrence of adjudicated probable dementia. Secondary cognitive outcomes included adjudicated mild cognitive impairment and a composite outcome of mild cognitive impairment or probable dementia.
Results Among 9361 randomized participants (mean age, 67.9 years; 3332 women [35.6%]), 8563 (91.5%) completed at least 1 follow-up cognitive assessment. 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 vs 176 in the standard treatment group (7.2 vs 8.6 cases per 1000 person-years; hazard ratio [HR], 0.83; 95% CI, 0.67-1.04). Intensive BP control significantly reduced the risk of mild cognitive impairment (14.6 vs 18.3 cases per 1000 person-years; HR, 0.81; 95% CI, 0.69-0.95) and the combined rate of mild cognitive impairment or probable dementia (20.2 vs 24.1 cases per 1000 person-years; HR, 0.85; 95% CI, 0.74-0.97).
Conclusions and Relevance Among ambulatory adults 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. Because of early study termination and fewer than expected cases of dementia, the study may have been underpowered for this end point.