Objectives: To identify clinically meaningful change in longitudinal assessment.
Design: A novel approach that qualifies item-level change over time by the degree to which it is clinically meaningful.
Setting: The classification method was tested by applying it to changes over 12 months in the frequency ratings of the items of a behavioral assessment instrument that is used commonly in clinical trials with Alzheimer's disease (AD) patients.
Participants: Responses from a cohort of 235 well characterized, community-dwelling subjects with AD were analyzed by this method.
Measurements: The approach allowed us to describe the proportions of items that emerged, ceased, worsened, and improved between the baseline and 12-month visits.
Results and conclusions: One-year change in the behavioral symptoms of persons with AD was used to exemplify the methodology. This approach can be used in other populations and with other measurements and was designed for analyses of clinical trial data. This method uses item-level changes to generate global impressions of clinically meaningful change; it also facilitates the definition of change that can be used in the clinical setting.