July 2015

Speed trap: Slowest seniors have increased mortality

In the moment: Gait

7ITMgait-iStock66889063-copyBy Emily Delzell

Gait speeds less than .6 m/s, a threshold that has been recommended as an indicator of mobility-related health problems, also confer a significantly increased risk of two-year mortality in hospitalized older patients, according to a recent prospective study.

Researchers at the University of Texas Medical Branch in Galveston tested gait speed in 289 hospitalized patients older than 65 years (61.6% female, age range 65-103 years), asking them to walk eight feet at their preferred speed. Participants had been admitted to an acute care for elders (ACE) hospital unit for cardiopulmonary disease or respiratory or gastrointestinal diagnoses, which together account for 87% of US ACE unit admissions.

The majority, 73.7%, had gait speeds at or below .6 m/s, a threshold below which physical therapists diagnose dismobility. Over the next two years, 17% (n = 49) of the patients died. All but four deaths occurred in people with gait speeds less than .6 m/s, who were two and half times as likely to die as those with faster gait speeds.

“Because gait speed reflects the combined functioning of the nervous, sensory, musculoskeletal, and cardiorespiratory systems, its assessment has been recommended as part of a standard in-patient geriatric evaluation,” said Glenn V. Ostir, MD, PhD, lead author of the study, which was epublished in June by the Archives of Physical Medicine and Rehabilitation.

In a 2014 Journal of the American Medical Association report, a mobility working group recommended that clinicians routinely test gait speed in older adults and use the .6 m/s threshold as an indicator of mobility-related health problems, which could help reveal a wide range of disorders.

“Gait speed could complement information traditionally collected on older patients, especially those who self-report little or no disability. For example, declines in walking performance have been associated with loss of independence, increased fall risk, and death, as well as variables that are more difficult to measure but may still impact medical recovery, such as depression, motivation, and social support,” said Ostir, who is a professor in the University of Maryland Department of Epidemiology & Public Health and director of its Division of Gerontology in Baltimore.

“Although testing gait speed can be easily and quickly done in almost all clinical settings, is highly reproducible, and reliably picks up small changes in physical function and health, it is not a routine part of health assessments in most clinical settings,” he said.

Having an easy-to-remember cut-point (ie, ≤ .6 m/s) could increase the clinical visibility of mobility-related health problems and serve as a diagnostic mechanism to activate resources directed at resolving potentially treatable conditions contributing to declines in health, Ostir said.

“Once a patient is identified with slow gait, added efforts may be made to identify potential causes of the problem, and, if appropriate, treatments initiated that could target cardiopulmonary, neurological, or musculoskeletal systems, and which could extend beyond the period of hospitalization,” he said.

Using gait speed to stratify health risks may also help personalize treatment goals.

“A diagnosis of dismobility could be used by physical therapists to develop measureable, meaningful mobility targets in consultation with the older patient and individualized plans to maintain those targets after hospital discharge,” Ostir said.

Gait speed, unlike many other health indicators, is often modifiable.

“In acutely ill hospitalized patients, each .1 meter per second increase in gait speed has been strongly linked to shorter hospital stays, reduced hospital costs, and fewer disabilities in activities of daily living,” he said. “It is not uncommon for older adults with subacute medical conditions to visit their primary care physician when their medical symptoms affect their function. Thus, declining or slow gait speed may capture unrecognized information about the severity or worsening of underlying chronic conditions.”

Sources:

Ostir GV, Berges IM, Ottenbacher KJ, et al. Gait speed and dismobility in older adults. Arch Phys Med Rehabil 2015 Jun 8. [Epub ahead of print]

Cummings SR, Studenski S, Ferrucci L. A diagnosis of dismobility—giving mobility clinical visibility: a Mobility Working Group recommendation. JAMA 2014; 311(20):2061-2062.

Purser JL, Weinberger M, Cohen HJ, et al. Gait speed predicts health status and hospital costs for frail elderly male veterans. J Rehabil Res Dev 2005;42(4): 535-546.

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