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Adequate treatment of high blood pressure (BP) can substantially lower the risk for dementia or cognitive impairment without dementia, new data indicated.

In a large study of Chinese adults with untreated hypertension, intensive BP management through medication and lifestyle changes cut the risk for dementia by 15% and cognitive impairment without dementia by 16% over 4 years.

“Our study is one of the first large-scale randomized controlled effectiveness trials to demonstrate a significant reduction in all-cause dementia associated with lowering BP,” lead author Jiang He, MD, PhD, with Department of Epidemiology, UT Southwestern Medical Center, Dallas, and colleagues wrote.

The study was published online on April 21 in Nature Medicine.

Proven Effective 

Past research had shown a strong link between untreated hypertension and cognitive problems in older adults. “However, definitive evidence supporting BP reduction for the primary prevention of dementia in hypertensive patients remains insufficient,” investigators noted.

In the China Rural Hypertension Control Project Phase-3 (CRHCP-3), researchers assessed the effectiveness of an intensive BP intervention (vs usual care) in reducing the risk for dementia among 33,995 adults aged 40 years or older with uncontrolled hypertension. This cluster-randomized trial was conducted in 326 villages in three provinces in China.

In the intervention group, trained nonphysician community healthcare providers initiated and titrated antihypertensive medications according to a simple stepped-care protocol to achieve a systolic BP (SBP) goal < 130 mm Hg and a diastolic BP (DBP) goal < 80 mm Hg, with supervision from primary care physicians. They also provided health coaching on home BP monitoring and lifestyle changes, such as weight loss, dietary sodium restriction, and reducing alcohol.

The usual care group was trained in BP management and received BP measurements during clinic visits.

A total of 14,541 participants in the intervention group and 13,594 participants in the usual care group had data for the primary outcome.

With the intervention, SBP decreased from 157.0 at baseline to 127.6 mm Hg at 48 months, while DBP decreased from 87.9 to 72.6 mm Hg. In the control group, SBP decreased from 155.4 to 147.7 mm Hg, and DBP fell from 87.2 to 81.0 mm Hg.

Over 48 months, SBP was reduced by 22.0 mm Hg and DPB by 9.3 mm Hg in the intervention group compared with the usual care group (P < .0001). This reduction in BP was associated with a 15% lower risk for all-cause dementia (risk ratio [RR], 0.85; P < .0001) and a 16% lower risk for cognitive impairment without dementia (RR, 0.84; P < .0001), the authors reported.

These associations remained significant after adjusting for key risk factors for dementia. The effectiveness of BP reduction on the risk for dementia was consistent across subgroups based on age, sex, education, history of cigarette smoking, body mass index, SBP, fasting plasma glucose, and 10-year atherosclerotic CVD risk at baseline.

At 48 months, 68% of participants in the intervention group achieved an SBP < 130 mm Hg and a DBP < 80 mm Hg compared with only 15% in the usual care group.

On average, patients in the intervention group took 3.0 antihypertensive medications, while those in the usual care group took 1.2 medications at the 48-month follow-up visit.

Adverse events were comparable between the two groups, and serious adverse events were significantly lower in the intervention group. There was no difference between the two groups in terms of injurious falls requiring medical care, symptomatic hypotension confirmed at a clinic visit or syncope needing medical care.

“The CRHCP-3 trial provides strong evidence for the effectiveness of antihypertensive treatment in reducing the risk of dementia in patients with hypertension. This proven-effective intervention should be widely adopted and scaled up to reduce the global burden of dementia,” the study team concluded.

A Wake-Up Call 

Several experts offered perspective on the study in a statement from the UK nonprofit Science Media Centre.

Masud Husain, FMedSci, professor of neurology, University of Oxford, Oxford, England, said, “This is a landmark study with a very large sample size and a robust effect. It’s a wake-up call to treat high blood pressure intensively, not just to protect the heart but also the brain.”

Mark Caulfield, MD, professor of clinical pharmacology, Queen Mary University of London, London, England, said the findings show that “optimizing blood pressure control convincingly reduces risk of dementia.”

“There have been prior studies suggesting correlation of blood pressure level and dementia risk, especially vascular dementia, but this is a very emphatic outcome of a trial. This is a really major advance in dementia prevention and will transform global blood pressure guidance and prevention strategies,” Caulfield added.

David Attwell, PhD, director of the Centre for Vascular Dementia Research, London, England, noted that while a 15% reduction in dementia development is “far from perfect prophylaxis, if uniformly implemented in people with high blood pressure in the population, it would greatly reduce both human suffering and the costs of health care systems.”

Several experts cautioned that the follow-up period was relatively short.

James Leiper, PhD, director of research, British Heart Foundation, London, England, said, “It will be important to see whether this reduced risk continues for longer than the 4-year follow-up period in the study, and whether similar effects are seen in other populations that receive the same treatment. If so wider use of high blood pressure treatment in people with the condition could be recommended to fight the growing impact of dementia.”

Richard Oakley, PhD, associate director of research and innovation at the Alzheimer’s Society, said it’s “encouraging that the intervention worked in real-world, rural settings using nonphysician healthcare workers, which may have implications for delivering care in areas with limited resources in the future. However, this 4-year study cannot tell us whether the benefits will last in the long-term so we will continue to follow this trial.”

This study had no commercial funding. He, Leiper, Attwell, Oakley, Caulfield, and Husain have declared no conflicts of interest.