Gait speed correlated with expected years of life remaining to people aged 65 years and older, with increased walking speed predicting longer life expectancy….
Dr. Stephanie Studenski of the division of geriatric medicine at the University of Pittsburgh, and her associates, stated that, for both sexes and at any age older than 65 years, a gait speed of 0.8 meters per second correlated with the median life expectancy for a person’s age and sex. Faster walking speeds consistently correlated with extended survival, they said.
They assessed the relationship between gait speed and survival in a pooled analysis using data from nine cohort studies of community-dwelling adults. Each study included at least 400 people, gait speed data at baseline, and follow-up for at least 5 years. All of the studies measured gait speed by having subjects walk at their usual pace from a standing start for 6-8 feet indoors.
There were 34,485 study subjects, including “substantial” numbers of African American and Hispanic patients, as well as 1,765 who were older than 85 years. Follow-up ranged from 6 to 21 years, with a median of 14 years. Gait speed ranged widely, from less than 0.4 meters per second (in 1,247 people) to more than 1.4 meters per second (in 1,491 people). There were 17,528 deaths during follow-up.
Predicted years of life remaining correlated with gait speed for patients of both sexes and all ages.
A walking speed of approximately 0.8 meters per second was associated with the predicted median life expectancy for a subject’s age and sex. Gait speeds faster than that rate predicted longer-than-average life expectancy, while slower gait speeds predicted shorter-than-average life expectancy. Gait speeds of 1.2 meters per second and faster predicted “exceptional” life expectancy, the investigators said
Gait speed “was especially informative after age 75 years” in patients who had no, or only minor, functional limitations. It may be less helpful in predicting life expectancy for patients who already report functional impairments and dependency on others for performing the activities of daily living, the investigators noted.
The data allowed Dr. Studenski and her colleagues to calculate survival estimates for a broad range of gait speeds, and to calculate absolute rates and median years of survival. “Compared with prior studies that were too small to assess potential effect modification by age, sex, race/ethnicity, and other subgroups, we were able to assess multiple subgroup effects with substantial power,” the researchers said.
“Because gait speed can be assessed by nonprofessional staff using a 4-meter walkway and a stopwatch, it is relatively simple to measure compared with many medical assessments,” they added.
In practice, gait speed can be used to identify elderly patients with a high probability of living 5-10 more years, who can then be targeted for preventive interventions that require a long time before benefits are realized. It can also identify patients at increased risk for early mortality, who can then be targeted for interventions to maximize health and survival, the researchers explained.
If gait speed is tracked over time, it can serve as an indicator that new health problems have arisen. It can also be helpful in stratifying risks from surgery or chemotherapy, the investigators said.