Gait speed associated with survival in older adults

Gait speed, age and sex may be all that are needed to predict survival in older adults, the authors of a new analysis concluded.

Researchers conducted a pooled analysis of nine cohort studies conducted between 1986 and 2000, using individual data from 34,485 community-dwelling older adults aged 65 years or older who were followed between six and 21 years. They reported results in the Jan. 5 Journal of the American Medical Association.

There were 17,528 deaths in the studied population. The overall five-year survival rate was 84.8% (95% CI, 79.6% to 88.8%) and the 10-year survival rate was 59.7% (95% CI, 46.5% to 70.6%). Faster gait speed was associated with survival in all studies (pooled hazard ratio per 0.1 m/s, 0.88; 95% CI, 0.87 to 0.90; P<0.001). At age 75, predicted 10-year survival across the range of gait speeds ranged from 19% to 87% in men and from 35% to 91% in women.

In the pooled sample, median survival for the age groups 65 through 74 years was 12.6 years for men and 16.8 for women; for 75 through 84 years, 7.9 years for men and 10.5 years for women; and for 85 years or older, 4.6 years for men and 6.4 years for women. As gait speed increased, so did predicted years of remaining life for each sex and age group, with a gait speed of about 0.8 m/s at the median life expectancy at most ages for both sexes. Gait speeds of 1.0 m/s or higher consistently predicted longer than expected survival.

Gait speed was "especially informative" after age 75, the authors wrote. In men, the probability of five-year survival at age 85 ranged from 0.3 to 0.88 and the probability of 10-year survival ranged from 0.18 to 0.86. In women, the probability of five-year survival remained greater than 0.5 until advanced age, but 10-year survival at age 75 ranged from 0.34 to 0.92 and at age 80 years from 0.22 to 0.86. Further adjustment for body mass index, smoking, systolic blood pressure, diseases, prior hospitalization, and self-reported health did not change the results (overall hazard ratio, 0.90; 95% CI, 0.89 to 0.91; P<0.001).

The authors wrote, "Gait speed could be considered a simple and accessible summary indicator of vitality because it integrates known and unrecognized disturbances in multiple organ systems, many of which affect survival. In addition, decreasing mobility may induce a vicious cycle of reduced physical activity and deconditioning that has a direct effect on health and survival."

Researchers predict that gait speed could be used:to identify those with a high probability of living for 5 or 10 more years, who may be appropriate targets for long-term preventive interventions,to identify patients at increased risk of early mortality and to target potentially modifiable risks,to monitor declines over time that might signal a new health problem,to stratify risks from surgery or chemotherapy, andto assess medical and behavioral interventions for their effect on gait speed in clinical trials.

An editorial concluded that gait speed is a useful research tool and may become a useful clinical one. However, the editorialist cautioned, "Functional limitations, cognitive impairment, hearing or visual problems, and balance or postural disorders may render the test more time-consuming than expected."