Measures of physical performance are regarded as useful objective clinical tools to estimate survival in elderly people. However, oldest old people, aged 85 years or more, are underrepresented in earlier studies and frequently unable to perform functional tests. We studied the association of gait speed and survival in a cohort of oldest old people and the association of Instrumental Activities of Daily Living by questionnaire and survival as an alternative prognostic marker of survival.

The Leiden 85-plus Study was used, a prospective population-based study with a follow-up period of 12 years. The study comprised 599 participants all aged 85 years at baseline. Survival rate was the measurement.

At age 85 years, 73 participants (12.2%) did not perform the walking test. Gait speed faster than 0.8 m/s was present in only 48 participants (9%), and gait speed faster than 1.0 m/s was present in 10 participants (1.9%). Risk for all-cause mortality was higher in participants with slow gait speed after 2 and 12 years of follow-up (hazard ratio [HR], 2.66; 95% confidence interval [CI], 1.49-4.75; P<.001; and HR, 2.04; 95% CI, 1.61-2.59; P=.100, respectively). Significance was lost after adjustment for common confounders. Poor Instrumental Activities of Daily Living ability was associated with an increased risk of mortality after 2 and 12 years of follow-up (HR, 6.11; 95% CI, 3.44-10.87; P<.001; and HR, 2.75; 95% CI, 2.22-3.40; P<.001, respectively). Adjustment for possible confounders attenuated the relation but remained significant.

The cutoff points for gait speed in oldest old people need to be reevaluated. In oldest old people aged 85 years, slow gait speed (≤0.40 m/s in women and ≤0.45 m/s in men) and Instrumental Activities of Daily Living disability are both predictors of survival. Assessment of Instrumental Activities of Daily Living could be a better tool for short- and long-term prognostication of survival in oldest old people.