Studies have shown that isolated systolic hypertension (ISH)—defined as having a systolic blood pressure (BP) of 140 mm Hg or higher with a diastolic BP less than 90 mm Hg—is associated with elevated risks for cardiovascular disease (CVD) in older adults. “There has been a sense among clinicians that ISH is a benign condition in younger people,” explains Donald M. Lloyd-Jones, MD, ScM. “This had led some experts to label ISH as pseudo-hypertension, but the data to support this belief are limited.”

A Look at Younger Patients

Few studies have looked at ISH in younger patients, despite research suggesting that its prevalence has increased in younger and middle-aged adults in recent years. For a study published in the Journal of the American College of Cardiology, Dr. Lloyd-Jones and colleagues assessed the risk for CVD in 27,000 patients aged 18 to 49 who did not have diagnosed coronary heart disease and were not taking antihypertensive therapy when they were assessed at baseline. Participants in the study were classified into one of the following groups:

  • Optimal-normal BP (systolic BP <130 mm Hg, diastolic BP <85 mm Hg).
  • High-normal BP (systolic BP 130 to 139, diastolic BP 85 to 89 mm Hg).
  • ISH.
  • Isolated diastolic hypertension (systolic BP <140 mm Hg, diastolic BP ≥90 mm Hg).
  • Systolic and diastolic hypertension (systolic BP ≥140 mm Hg, diastolic BP ≥90 mm Hg).

With access to the Chicago Heart Association Study database and linkage to the National Death Index, the study team was able to assess follow-up data on the cause of death among participants as well as 35-year outcomes, with an average follow-up of about 31 years. “It is necessary to follow younger patients for the long term because they don’t typically have many cardiovascular events in the near term,” says Dr. Lloyd-Jones.

 Important Results

The most important finding from the study, according to Dr. Lloyd-Jones, was that the pattern of ISH in younger patients was associated with a higher risk for cardiovascular mortality, and for coronary mortality in particular. “When compared with younger men who had normal BP levels, those with ISH were at about 15% higher risk for cardiovascular mortality over the next 30 years,” he explains. “For younger women with ISH, the risk was even more pronounced. Overall, patients with ISH had a 1.5- to 2.0-fold higher risk for 30-year cardiovascular mortality than those with normal BPs. Our findings suggest that it is increasingly important to detect ISH in younger individuals. Clinicians need to become aware of this correlation.”

The highest risks for CVD mortality among the various BP patterns studied were seen among participants with elevations in both systolic and diastolic BP (Figure). However, ISH was clearly associated with higher risk when compared with normal BP, explains Dr. Lloyd-Jones. “Our study is the first to show this observation in a large dataset of younger individuals,” he adds.

Even after adjusting for comorbid conditions like diabetes, smoking, or elevated BMI, patients with ISH had significantly higher rates of death from CVD, coronary heart disease, and stroke when compared with those with normal BPs. “There seems to be an independent association of ISH with higher mortality risks,” says Dr. Lloyd-Jones.

Incorporating the Findings

When ISH is observed in younger patients, the first step should be to confirm the finding with a repeat BP measurement in the near future, according to Dr. Lloyd-Jones. “If the repeat measurement confirms that the patient has ISH, intensive lifestyle modifications—including losing weight, increasing physical activity, and reducing sodium in the diet— should be considered,” he says. “Whereas physicians might be reluctant to prescribe a medication immediately, research has shown that lifestyle modifications can effectively lower BP. Failure to address these modifications will likely lead to negative implications over the long term, particularly for women.”

If attempts at lifestyle changes do not result in improvements in systolic BP, Dr. Lloyd-Jones says it may be reasonable to have a conversation with patients about whether or not medical therapy should be considered. “It’s important to note, however, that few clinical trials have shown that medications in young adults effectively prevent future cardiovascular events,” he adds. “It is paramount that clinicians are aware of the risks associated with ISH and discount the notion that it may just be pseudo-hypertension.”