Using timed up and go and usual gait speed to predict incident disability in daily activities among community-dwelling adults aged 65 and older.

OBJECTIVES: To compare the ability of Timed Up and Go (TUG) and usual gait speed (UGS) to predict incident disability completing basic activities of daily living (ADL) and instrumental ADL (IADL) in older adults free of disability at baseline, and to provide estimates for the probability of incident disability at different levels of baseline mobility performance.

DESIGN: Data from the first 2 waves of The Irish Longitudinal Study on Ageing, a study assessing health, economic, and social aspects of ageing in adults aged ≥50 years.

SETTING: A nationally representative, population-based sample of community-dwelling adults.

PARTICIPANTS: Participants aged ≥65 years who completed mobility tests during a health assessment, had no reported difficulty in ADL/IADL, and had a Mini-Mental State Examination score ≥24 were re-interviewed after 2 years (n=1664).

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Participants completed the TUG and UGS at baseline and indicated difficulty in a number of basic ADL and IADL at follow-up.

RESULTS: Receiver operating characteristic analysis indicated that TUG and UGS are acceptable tools to predict disability in ADL and IADL (area under the curve [AUC]=.65-.75) with no significant difference between them (P>.05). Both were excellent predictors of difficulty in higher-level functioning tasks such as preparing hot meals, taking medications, and managing money (AUC>.80). Predictive probabilities were obtained across a range of performance levels.

CONCLUSIONS: TUG and UGS have similar predictive ability in relation to incident disability in basic ADL and IADL. Predictive probabilities can be used to identify those most at risk and in need of particular services. Since improving physical function can prevent or delay dependence in ADL/IADL, TUG and UGS can also provide performance goals and feedback during exercise interventions.