The raised blood pressure of hypertension causes a great deal of downstream damage. It is a way for low-level biochemical damage associated with aging to become actual physical damage to the body. Pressure damage can occur in delicate tissues throughout the body, and raised blood pressure increases the pace at which capillaries and other small vessels rupture. Further, increased blood pressure can accelerate the development of atherosclerosis, and also contributes to the pathological enlargement and weakening of heart muscle. All of this downstream harm is why forcing a reduction in blood pressure, without addressing any of the underlying cell and tissue damage that causes hypertension, can nonetheless produce benefits to long-term health. Antihypertensive medications do not in any way touch upon the biochemistry of aging, but rather act to force regulatory mechanisms of blood pressure into a certain state.
There is a great deal of epidemiological evidence to show that higher blood pressure correlates with increased mortality and risk dementia. There is also a good deal of evidence for control of blood pressure via hypertensive drugs to reduce mortality and risk of dementia. Today’s notes on recent research add to this evidence, reporting on a recent study in China. In this context, it is worth noting that in recent years it has become clear that lower blood pressure is better even in the normal range, that reducing below the 120s mmHg systolic blood pressure that are the present target continues to produce benefits.
Researchers evaluated the effectiveness of lowering blood pressure on dementia risk among people with high blood pressure. The study was conducted in 326 villages in rural China and included approximately 34,000 adults, ages 40 and older, with untreated blood pressure of 140/90 mm Hg or higher, or 130/80 mm Hg or higher for people at high risk for cardiovascular disease or those currently taking blood pressure medication. Half of the villages were randomly assigned to a village doctor-led intensive blood pressure intervention strategy, and half of the villages were randomly assigned to usual care. Patients in the usual care villages received their hypertension management from local village doctors or primary care physicians at township hospitals as part of routine health service covered by the China New Rural Cooperative Medical Scheme (a health insurance plan covering approximately 99% of rural residents for basic health-care services in China).
In the intervention group, trained village doctors initiated and adjusted antihypertensive medications based on a straightforward treatment protocol to achieve a goal of lowering systolic blood pressure to less than 130 mm Hg and diastolic blood pressure to less than 80 mm Hg, with supervision from primary care physicians. The stepwise protocol for hypertension management included a treatment algorithm, selection of medication, review of contraindications of medications and, finally, strategies to adjust dose. They also provided discounted and free blood pressure medications to patients and conducted health coaching on lifestyle modifications, home blood-pressure measurement and medication adherence.
The analysis found that the people in the intervention group showed significant improvement in blood pressure control and reduced dementia and cognitive impairment, no dementia compared to those who received usual care. The average blood pressure in the intervention group at 48 months was 128/73 mm Hg, compared to 148/81 mm Hg in the usual care group. On average, systolic blood pressure decreased by 22 mm Hg and diastolic blood pressure decreased by 9 mm Hg among people in the intervention group compared to usual care. People in the intervention group had 15% lower risk of dementia and 16% lower risk of memory impairment compared to the group that received usual care. Serious adverse events, such as hospitalizations and death from all causes, were also less frequent in the intervention group.