Comparison of complex versus simple activity of daily living staging: validation of simple stages.

Abstract

To compare activities of daily living (ADL) staging based on 2-level responses to ADL difficulty questions (simple ADL stages) with ADL staging based on 4-level ADL question responses (complex ADL stages). Analysis of the Second Longitudinal Study of Aging, a prospective cohort study, using descriptive statistics and logistic regression. Participants' homes. Community-dwelling persons (N=9447) aged ≥70 years in 1994. Not applicable. (1) Agreement and face validity: baseline simple ADL stage; (2) construct validity: baseline health, difficulty, and need characteristics; (3) prognostic comparison (determined at the Wave 2 interview): primary-nursing home use and/or death; secondary-death. The systems showed good agreement (κ=.75). The simple ADL stages stratified people into distinct groups and reflected the expected stepwise increases from stage 0 to stage IV in health and need characteristics, such as the prevalence of home-related challenges (2.9%-84.5%) and perceived need for home modifications (2.1%-33.6%). In comparing the prognostic ability using the primary outcome, the complex system model demonstrated slightly increased discrimination between milder stages and a slightly higher C statistic (.666 vs .664). Although complex staging appears slightly better at classifying people into distinct prognostic strata with respect to nursing home use and/or death at Wave 2, simple ADL stages demonstrate strong, clinically relevant associations with health and need characteristics.