Biological Age, Not Years Alone, Should Guide BP Treatment in Elderly

Shelley Wood

June 14, 2014

ATHENS, GREECE — New data from the Longitudinal Aging Study Amsterdam (LASA) offer a boost to calls for physicians to consider "biological" age over chronological age when managing blood pressure in the elderly[1]. In a LASA analysis presented here at HYPERTENSION 2014 , a joint conference of the European Society of Hypertension (ESH) and the International Society of Hypertension (ISH), Dr Majon Muller (Leiden University Medical Center, the Netherlands) showed that both high and low diastolic blood pressure (DBP) are associated with increased cardiovascular risk, depending on the relative fitness or frailty of the subject.

"It's important when you treat an older patient with hypertension not to look only at the chronological age, which is what clinicians tend to do—one 85-year-old could be totally different from another 85-year-old, in terms of function and biological age," she told heartwire . "There is a group of older people who are really fit, and they should probably be treated the same as younger patients, and there is a group of older people who are really frail, and then you probably have to be careful treating too aggressively, or [consider whether you should] even be treating at all."

Muller and colleagues tracked all-cause mortality over 15 years of follow-up in 1466 older men and women participating in LASA, with all participants stratified at baseline according to their "biological" age. This was derived from a scoring system that took into account their fitness—arbitrarily defined by gait speed during the 6-m-walk test—and cognitive function by Mini Mental State Examination (MMSE) score.

Young at Heart?

Dr Majon Muller

Mean chronological age in the study was 76 at baseline, but 59% of patients were categorized as frail by the biological age score, while the remaining 41% were deemed fit.

Over a median of 11 years, 1008 participants died. In the population as a whole, systolic blood pressure (SBP) had no relationship with mortality risk. By contrast, both high and low DBP were linked to increased mortality.

When the mortality risk according to diastolic blood pressure was analyzed by biological age, a striking pattern emerged, Muller said.

For fit elderly patients, a high DBP (>90 mm Hg) was associated with a 50% increase in mortality; however, no significantly increased risk was seen for a low DBP (<70 mm Hg) in these patients.

By contrast, for frail elderly patients, a low DBP was associated with a 50% increased risk of dying during the follow-up period, while no such risk was seen among frail elderly with DBPs higher than 90 mm Hg.

"Future research should focus on whether we can use biological age to identify those older people who might benefit or not from antihypertensive treatment and maybe whether less stringent targets could be used in the frail, older subjects," Muller concluded. "The ultimate goal is personalized treatment so that we can avoid overtreatment of the frail and undertreatment of the fit."

 
The ultimate goal is personalized treatment so that we can avoid overtreatment of the frail, and undertreatment of the fit.
 

Commenting on the study, Dr Michael Weber (State University of New York, Brooklyn), one of the session moderators, called the study "provocative" but noted that it was at odds with the Framingham study in which both low systolic and low diastolic BP appeared to track with risk in older subjects.

In response, Muller acknowledged she, too, was surprised to see no link with low SBP but noted that patients in this LASA analysis were "a little older" than the Framingham subjects. Moreover, the range in SBP values for fit and frail subjects was not large, potentially limiting the ability of researchers to see a difference.

A Simple Score vs Gut Instinct

The "Biological Age Combination Score" used by Muller and colleagues awarded a 0 to subjects with a gait speed of >0.8 m/s, a 1 for a gait speed <0.8 m/s, and a 2 for subjects who did not complete the test. A 0 was also given to subjects who scored >28 points on the MMSE, a 1 if they scored 27 to 28 points, and a 2 if they scored <26 points. Fit was then defined as score of 0-1 and frail by a score of 2-4.

To heartwire , Muller clarified that the score has not been validated, but it offers a simple tool physicians can use to try to gauge biological age. Many physicians, however, are already comfortable trusting their gut feeling as to whether a patient is physically or mentally frail.

"I think many physicians do this instinctively, and maybe the gut feeling of the physician is enough," she said. In fact, she continued, it may not matter what tool is used to estimate biological age, as long as physicians are aware of its importance. "This score may help especially for less experienced physicians to have a tool to quantify the fitness of the person. If you are experienced, maybe that gut feeling is enough, but if not, you could apply these tests, just to make sure that you can quantify it."

Muller had no conflicts of interest.

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