Intensive Blood Pressure Control: Too Close for Comfort?

Study Finds Aggressively Reducing SBP in Elderly Can Boost Fall, Syncope Risk

September 12, 2018 03:12 pm Michael Devitt

Last year, the AAFP declined to endorse a hypertension (HTN) guideline issued by the American Heart Association (AHA), the American College of Cardiology (ACC) and nine other health professional organizations that recommended treating HTN with lifestyle changes and medications as needed beginning at a blood pressure (BP) level of 130/80 mm Hg instead of the commonly accepted threshold of 140/90 mm Hg.

[older man getting blood pressure reading]

Now, new research suggests that aggressive HTN treatment to targets similar to what the AHA/ACC guideline recommended may produce unintended adverse consequences in many patients.

In a cross-sectional study(www.ajpmonline.org) involving nearly half a million people that was published in the American Journal of Preventive Medicine (AJPM), researchers found that if older patients taking prescribed medications to treat their HTN experienced unusually low BP (i.e., a systolic BP [SBP] level of less than 110 mm Hg) at least once in a given year, they were twice as likely to faint or experience a fall as those whose SBP remained at 110 mm Hg or higher.

Story Highlights
  • New research suggests that intensive blood pressure (BP) control may increase the risk of falls and fainting in older patients with hypertension.
  • Patients who experienced unusually low BP at least once in a given year were twice as likely to fall or faint as those who did not.
  • Family physicians should consider a variety of factors when determining target BP levels for older patients who have hypertension.

"Efforts to reduce blood pressures for patients with hypertension are an important factor in reducing the risk of heart attack and stroke," said study lead author John Sim, M.D., a clinician investigator in the Division of Nephrology and Hypertension at Kaiser Permanente Los Angeles Medical Center and assistant clinical professor at the David Geffen University of California, Los Angeles, School of Medicine, in a news release.(share.kaiserpermanente.org) "But our study shows that attaining a lower blood pressure could create a subpopulation of patients whose blood pressures may go too low, which can pose risk for serious falls and fainting."

Study Details

The AJPM researchers analyzed the health records of 477,516 individuals actively being treated for HTN during a one-year observation period. Mean patient age was 65, and women made up 53 percent of the study cohort.

The researchers used the lowest SBP reading measured within the observation period as the minimum SBP and the mean value of all blood pressure readings during the observation period to determine the mean SBP.

The mean BP of the study population overall was 129/72 mm Hg. Most participants underwent multiple BP measurements, with 75 percent having three or more measurements during the observation period. Thirty-six percent of participants were taking three or more antihypertensive drugs, and 21 percent had three or more comorbidities.

By the Numbers

Among the study's most important findings:

  • 26.7 percent of the study population (127,581 participants) had at least one SBP measurement of less than 110 mm Hg during the observation period, and 3.1 percent (14,724 participants) had a mean SBP of less than 110 mm Hg.
  • 3.2 percent of the study population (15,419 patients) experienced a serious fall, fainted, or both during the observation period.
  • 5.7 percent of those with a minimum SBP of less than 110 mm Hg experienced a serious fall or syncope compared with 2.3 percent of those with a minimum SPB of 110 mm Hg or higher.
  • 5.4 percent of those with a mean SBP of less than 110 mm Hg experienced a serious fall or syncope compared with 3.2 percent of those with a mean SBP of 110 mm Hg or higher.
  • Overall, the multivariable odds ratio (OR) for a serious fall and syncope among those with a minimum SBP of less than 110 mm Hg was 2.18 compared with those with a minimum SBP of 110 mm Hg or higher.
  • Similarly, the multivariable OR for a serious fall and syncope among those with a mean SBP of less than 110 mm Hg was 1.54 compared with those with a mean SBP of 110 mm Hg or higher.
  • Women, non-whites, patients with dementia and those taking alpha-receptor antagonists were more likely to experience a serious fall or syncope.

"These findings suggest that frequent BP monitoring and low BP thresholds for medication modification should be considerations in the current HTN treatment environment," the authors wrote. "With the growing emphasis on intensive BP control, adverse treatment risk and treatment among high-risk populations will be important concerns when individualizing HTN treatment."

Implications for Family Physicians

The AJPM findings should raise a red flag for family physicians who see older patients for a number of reasons.

First, older patients are more likely(www.ncbi.nlm.nih.gov) to experience orthostatic hypotension than their younger counterparts. And because their bodies don't compensate for rapid reductions in BP as quickly as those of younger patients and their reflexes are slower, they are at increased risk of becoming dizzy and/or falling.

It's also well known that serious falls in the elderly are a major health concern. Results from a multitude of studies have shown that serious falls are a leading cause of injury-related hospitalization, a strong predictor of being admitted to a nursing home and the leading cause of injury-related death in these patients. And once an elderly person has a serious fall, he or she is up to six times more likely to experience another fall in the future.

Finally, a core question remains unanswered: What should the target BP be for patients who are taking antihypertensive drugs?

According to Jennifer Frost, M.D., medical director for the Academy's Health of the Public and Science Division, several items should be taken into account before defining any such goal.

"Every patient is different, with different risks, comorbidities and values," Frost told AAFP News. "Whenever possible, treatment should be based on all of these factors."

In 2017, Frost noted, the AAFP and the American College of Physicians (ACP) collaborated on a clinical practice guideline that addresses BP targets in adults older than 60 -- a patient population similar to that in the AJPM study. That AAFP/ACP guideline recommends an SBP target of less than 150 mm Hg for individuals older than 60 who have persistent SBP of 150 mm Hg or higher.

Regarding this particular patient group, said Frost, "The evidence shows that the benefit of strict blood pressure control in this population is small, while there are serious potential harms, as demonstrated in this study."

The AHA/ACC guideline defines stage 1 HTN(www.onlinejacc.org) as an SBP level of 130-139 mm Hg or a diastolic BP (DBP) of 80-89 mm Hg, and stage 2 HTN as an SBP level of 140 mm Hg or higher or DBP of 90 mm Hg or higher.

The AAFP, meanwhile, continues to endorse the "2014 Evidence-Based Guideline for the Management of High Blood Pressure in Adults"(jamanetwork.com) developed by panel members appointed to the Eighth Joint National Committee (JNC8). The JNC 8 guideline does not provide a specific definition of HTN, instead recommending pharmacotherapy to treat to a BP goal of less than 140/90 mm Hg for most patients with HTN and to less than 150/90 mm Hg for adults 60 or older who have HTN.

Related AAFP News Coverage
AAFP to Review AHA/ACC Redefinition of High Blood Pressure
Academy Continues to Endorse JNC8 Hypertension Guideline

(11/15/2017)

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