Staging functional independence validity and applications.

Abstract

OBJECTIVES: To establish construct and predictive validity of the activities of daily living, sphincter-management, mobility, and executive-function (ASME) staging system of functional independence and to describe potential applications. DESIGN: National data were used to validate the stages. Sensitivity to functional change was addressed by comparing patients' stages at discharge to their stages at admission. Construct validity was assessed by examining stage distribution differences among groups of patients classified by impairment category. Predictive validity was determined by the degree to which high stages at admission predict discharge to the community and low stages at admission predict serious morbidity or mortality. SETTING: Inpatient rehabilitation facilities. PARTICIPANTS: Data from 231,686 individuals discharged from 560 US inpatient rehabilitation facilities in 1995. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Stage at rehabilitation discharge, community discharge, acute hospital discharge, or death while in rehabilitation. RESULTS: More than 90% of patients were discharged at a higher stage in at least 1 domain while not declining in any other domain. The odds (95% confidence interval) of community discharge for patients admitted at the highest compared with the lowest stage varied from 2.1 (1.9-2.2) to 3.1 (2.9-3.2), depending on the domain. The odds of acute hospitalization or death were reduced at the highest stages, compared with the lowest, by a factor ranging from .33 (.22-.49) to .65 (.61-.69). CONCLUSIONS: The ASME stages appear valid and sensitive to change. Functional Independence Staging (FIS) has relevance in establishing prognoses and in selecting among therapeutic modalities. FIS will facilitate the identification of meaningful functional goals and interpretable clinical trial endpoints. One of its most important applications could be in the establishment of outcome indicators for quality monitoring under the prospective payment system.