Adults older than 75 being treated for high blood pressure, especially those with complex health problems, may be at risk for additional cognitive decline if their systolic blood pressure is 130 mmHg or lower, according to a study published in the March/April issue of Annals of Family Medicine.
Healthy blood pressure is defined as 120/80 or less; anything above 140/90 is considered high blood pressure or hypertension. After a series of high blood pressure trials, the American College of Cardiology/American Heart Association updated their guidelines to recommend keeping systolic blood pressure lower than 130 for non-institutionalized older patients. However, these trials often excluded older, frail patients with complex health problems, including multiple chronic conditions, mental health issues, medication-related problems, and social vulnerability, making it difficult to generalize or apply these findings to other populations.
To assess whether low systolic blood pressure and cognitive decline are similarly associated in older adults being treated for high blood pressure, a team of Swiss and Dutch researchers analyzed data from 1,266 participants—average age 82.4 years; 69 percent women—from the Integrated Systematic Care for Older Persons (ISCOPE), a population-based prospective study with a one-year follow-up.
Patients were divided into groups based on their systolic blood pressure—less than 130, 130 to 150, and greater than 150—which was calculated by averaging the last five measurements taken the year before the study. They were also grouped according to whether they took blood pressure-lowering drugs and had any change in cognitive function from the start of the study to follow-up.
The researchers used a series of tests and questionnaires to determine participants’ cognitive function, their ability to care for themselves and live independently, and their quality of life.
Participants on blood pressure medication whose systolic blood pressure was lower than 130, registered a 0.9-point decline on the cognitive test while those whose systolic blood pressure was more than 150 had a 0.14-point decline. The findings were similar when the researchers restricted their analysis to patients with complex health problems. This association was not seen in patients without complex health problems.
Patients being treated for high blood pressure were more likely to have a systolic blood pressure of more than 150 compared to those not being treated. They also were more likely to have cardiovascular disease and diabetes. In addition, they were less able to take care of themselves or live independently and had a lower quality of life.
Based on their findings, the researchers are calling for new trials to test the long-term effectiveness and safety of prescribing antihypertensive drugs that raise systolic blood pressure, especially in frail older patients.
They concluded that because older patients are more likely to be frail and decline cognitively more quickly, “clinicians are advised to be cautious about lowering systolic blood pressure too much.”