Blood pressure management and dementia prevention: Is lower better?

Contributed by: Dr. Vivian Ewa - View bio

Case

Elaine is a 78-year-old woman with hypertension and is on multiple medications. She is concerned about memory changes and has read that well-controlled blood pressure will protect her from dementia.

Background

Nearly a quarter of Canadian adults have hypertension.¹ It affects more than 75% of people aged 65 years and older and has been identified in observational studies as a modifiable risk factor for MCI and dementia.² As Alzheimer’s disease and related dementias are projected to affect about 115 million people worldwide by 2050,³ optimizing blood pressure management is essential.

In February 2019 the researchers of SPRINT MIND published their findings on the effect of intensive versus standard blood pressure control on probable dementia.⁴ Results were based on follow-up of participants from the SPRINT trial,⁵ which showed significantly lower rates of the primary composite outcome in the intensive versus standard treatment group (hazard ratio, 0.73; 95% CI, 0.60 to 0.90; P=0.003). However, there were more reports of adverse events such as hypotension, syncope, electrolyte abnormalities and acute kidney injury in the treatment group. The SPRINT study was terminated after 3.26 years due to the significant impact on cardiovascular outcomes and all-cause mortality. The SPRINT MIND researchers followed the participants for three more years to determine the impact of intensive blood pressure control on risk for dementia. Of the 9,361 participants recruited in the original SPRINT trial,⁵ 149 in the intensive treatment group developed dementia compared to 176 in the standard treatment group. Results were not significant (7.2 vs 8.6 cases per 1,000 person-years; hazard ratio, 0.83; 95% CI, 0.67-1.04). Researchers concluded that intensive blood pressure control in ambulatory adults with a target of less than 120 mmHg compared to 140 mmHg did not result in a significant reduction in the risk of probable dementia.⁴ Of significance in the SPRINT trial were the exclusion criteria, which were patients with type 2 diabetes, advanced kidney disease, heart failure and prior stroke. As a result, frail individuals with the highest risk of cerebrovascular burden were excluded from the study. Those with one-minute standing systolic blood pressure of less than 110mm Hg were also excluded.⁵

Back to the case

Further review of Elaine’s history reveals a history of coronary heart disease and type 2 diabetes on oral hypoglycemic therapy. Hba1c in the last year has ranged from 7.3 - 7.5%. Five years ago, she had a mild stroke with no residual focal deficits. Other medical history includes osteoarthritis and osteoporosis. Elaine has a history of falls with two falls in the last three months. She mobilizes with a 4-wheel walker and has Home Care assistance for bathing. She reports changes in short-term memory and difficulties with finding her words. She self-administers medications from a blister pack. Her medications include Hydrochlorothiazide 25mg daily, Amlodipine 5 mg daily, Ramipril 5mg daily, Metformin 1000mg BID, Tylenol 1000mg BID, Vitamin D 2000 units daily and ASA EC 81mg daily.

On clinical examination, Elaine’s lying blood pressure is 145/ 80 mm Hg with a heart rate of 64. On standing for one minute, her blood pressure is 118/ 70 with a heart rate of 76. She is symptomatic with postural drop. The rest of her physical exam is unremarkable. Significant recent laboratory results show a hypokalemia of 3.0 and blood pressure taken by Home Care shows sitting systolic blood pressures that range from 120-130mm Hg.

You discuss your clinical findings with Elaine and recommend a reduction in Hydrochlorothiazide to 12.5mg, with a plan to deprescribe if her blood pressure remains less than 140 mm Hg, given falls risk, hypokalemia and symptomatic postural hypotension. You discuss the results of the study in layman’s terms and emphasize the exclusion criteria and adverse effects of intensive blood pressure control, some of which she is experiencing. With regards to dementia risk, you encourage ongoing physical activity and socialization to promote cognitive resilience.⁶

Bottom line

Blood pressure targets in the older adults should take into consideration frailty and chronic disease burden. The risk of adverse events is higher in frail older adults with multimorbidity, so blood pressure targets need to be modified to reduce this risk.⁷

References

1. DeGuire J, Clarke J, Rouleau K, Roy J, Bushnik T. Blood pressure and hypertension. Health Rep. 2019;30(2):14-21.
2. Whelton PK, Carey RM, Aronow WS, Casey DE, Jr., Collins KJ, Dennison Himmelfarb C, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018;71(6):1269-324.
3. Prince M, Bryce R, Albanese E, Wimo A, Ribeiro W, Ferri CP. The global prevalence of dementia: a systematic review and metaanalysis. Alzheimers Dement. 2013;9(1):63-75.e2.
4. Williamson JD, Pajewski NM, Auchus AP, Bryan RN, Chelune G, Cheung AK, et al. Effect of Intensive vs Standard Blood Pressure Control on Probable Dementia: A Randomized Clinical Trial. Jama. 2019;321(6):553-61.
5. Wright JT, Jr., Williamson JD, Whelton PK, Snyder JK, Sink KM, Rocco MV, et al. A Randomized Trial of Intensive versus Standard Blood-Pressure Control. N Engl J Med. 2015;373(22):2103-16.
6. Ngandu T, Lehtisalo J, Solomon A, Levalahti E, Ahtiluoto S, Antikainen R, et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet. 2015;385(9984):2255-63.
7. Beckett NS, Peters R, Fletcher AE, Staessen JA, Liu L, Dumitrascu D, et al. Treatment of Hypertension in Patients 80 Years of Age or Older. New England Journal of Medicine. 2008;358(18):1887-98.