Slower gait speed predicts decline in Instrumental Activities of Daily Living in community-dwelling elderly: 3-year prospective finding from Living Profiles of Older People Survey in Korea

Abstract

Slower gait speed is a good predictor of falls, dependency, disability, and mortality. However, the cutoff point of the gait speed to best predict the bad outcomes is controversial. The purpose of this study was to determine the cutoff point of gait speed that best predicts Instrumental Activities of Daily Living (IADL) dependency. The study targeted 8000 people aged ≥ 65 years who had been enrolled in 2008 and followed up in 2011 for the Living Profiles of Older People Survey in Korea. The population was divided into an independent group and a dependent group with 2011 Korean Instrumental Activities of Daily Living (K-IADL) scores of 10 and ≥ 11, respectively. The gait speed was measured as the time taken to walk 2.5 m at a usual pace without any help, and the best result of two trials was chosen for analysis. The area under the curve was highest (0.642) at gait speed of 0.6 m/s, with a sensitivity and specificity of 68.44% and 55.09%, respectively. The dependency hazard ratio of IADL was statistically significant in the group with gait speed less than 0.6 m/s, 1.974 (95% confidence interval, 1.646–2.367). The dependency hazard ratio of IADL was also statistically significant in the same group after adjusting for all relevant variables, 1.613 (95% confidence interval, 1.332–1.955). The gait speed of 0.6 m/s may be considered as the new standard of a screening tool to predict IADL dependency in Korean people aged ≥ 65 years.