Time in Range or Treat to Target?
With respect to dementia risk, does treating hypertension to a specific target make a difference, or is it the time spent in a healthy blood pressure range?
“Observational studies and a post hoc analysis of the SPRINT MIND trial suggest that more time spent in a healthy blood pressure range or more stable blood pressure are associated with lower dementia risk,” Dr. Moran said. Citing results of the CHRC program and SPRINT MIND trial, he suggested that while a dose-response effect (the lower the blood pressure, the lower the dementia risk) hasn’t been definitively demonstrated, it is likely the case.
In his practice, Dr. Moran follows ACC/AHA guidelines and prescribes antihypertensives to get blood pressure below 130/80 mm Hg in individuals with hypertension who have other high-risk factors (cardiovascular disease, diabetes, chronic kidney disease, or high risk for these conditions). “The treatment rule for people with hypertension without these other risk factors is less clear — lowering blood pressure below 140/90 mm Hg is a must; I will discuss with patients whether to go lower than that.”
“The relative contributions of time in range versus treating to a target for blood pressure require further study,” said Dr. Elkind. “It is likely that the cumulative effect of blood pressure over time has a big role to play — and it does seem clear that midlife blood pressure is even more important than blood pressure late in life.”
That said, he added, “In general and all things being equal, I would treat to a blood pressure of < 120/80 mmHg,” given the SPRINT trial findings of greater benefits when treating to this systolic blood pressure goal. “Of course, if patients have side effects such as lightheadedness or dizziness or other medical conditions that require a higher target, then one would need to adjust the treatment targets.”
According to Dr. Fuster, targets should not be the focus because they vary. For example, the ACC/AHA guidelines use < 130/80 mm Hg, whereas the European Society of Hypertension guidelines and those of the American Academy of Family Physicians specify < 140/90 mm Hg and include age-based criteria. Because there are no studies comparing the outcomes of one set of guidelines vs another, Dr. Fuster thinks the focus should be on starting treatment as early as possible to prevent hypertension leading to dementia.
He pointed to the ongoing PESA trial, which uses brain MRI and other tests to characterize longitudinal associations among cerebral glucose metabolism, subclinical atherosclerosis, and cardiovascular risk factors in asymptomatic individuals aged 40-54. Most did not have hypertension at baseline.
A recently published analysis of a subcohort of 370 PESA participants found that those with persistent high cardiovascular risk and subclinical carotid atherosclerosis already had signs of brain metabolic decline, “suggesting that maintenance of cardiovascular health during midlife could contribute to reductions in neurodegenerative disease burden later in life,” wrote the investigators.
Is It Ever Too Late?
If starting hypertension treatment in midlife can help reduce the risk for cognitive impairment later, can treating later in life also help? “It’s theoretically possible, but it has to be proven,” Dr. Fuster said. “There are no data on whether there’s less chance to prevent the development of dementia if you start treating hypertension at age 70, for example. And we have no idea whether hypertension treatment will prevent progression in those who already have dementia.”
“Treating high blood pressure in older adults could affect the course of further progressive cognitive decline by improving vascular health and preventing strokes, which likely exacerbate nonvascular dementia,” Dr. Elkind suggested. “Most people with dementia have a combination of vascular and nonvascular dementia, so treating reversible causes wherever possible makes a difference.”
Dr. Elkind treats older patients with this in mind, he said, “even though most of the evidence points to the fact that it is blood pressure in middle age, not older age, that seems to have the biggest impact on later-life cognitive decline and dementia.” Like Dr. Fuster, he said, “the best strategy is to identify and treat blood pressure in midlife, before damage to the brain has advanced.”
Dr. Moran noted, “The latest science on dementia causes suggests it is difficult to draw a border between vascular and nonvascular dementia. So, as a practical matter, healthcare providers should consider that hypertension treatment is one of the best ways to prevent any category of dementia. This dementia prevention is added to the well-known benefits of hypertension treatment to prevent heart attacks, strokes, and kidney disease: ‘Healthy heart, healthy brain.’ ”
“Our BP [blood pressure] control rates overall are still abysmal,” Dr. Handberg added. Currently around one in four US adults with hypertension have it under control. Studies have shown that blood pressure control rates of 70%-80% are achievable, she said. “We can’t let patient or provider inertia continue.”
Dr. Handberg, Dr. Elkind, Dr. Moran, and Dr. Fuster declared no relevant conflicts of interest.
A version of this article first appeared on Medscape.com.