Responsiveness of Health Status Measures to Change among Older Adults

OBJECTIVE: This study examines the ability of commonly used self-reported health status measures to detect important changes in health (responsiveness) in older adults. DESIGN: We compared changes in health status measures over the year among subgroups of a cohort of seniors: those who experienced an intervening illness, hospitalization or increase in drug regimen, and those who didn't. Differences between the two groups in changes in the measures were quantitated using Guyatt's responsiveness statistic and receiver operating characteristic curves (ROC). SETTING: Staff model HMO. PARTICIPANTS: 1379 senior HMO enrollees who were participants in a health promotion trial and provided complete information at baseline and one year later. MEASUREMENTS: The following self-reported health status measures were evaluated: restricted activity days, bed disability days, the Medical Outcomes Study physical function scale, self-evaluated health, and a positive affect scale. MAIN RESULTS: All measures except the positive affect scale were able to discriminate significantly between seniors who were or were not hospitalized and/or reported a major illness in the intervening year. The two disability days measures showed the best responsiveness for all indicators of worsening health and included 70%-80% of the area under the ROC curves for major illness defined by hospitalization or self-report. CONCLUSIONS: Commonly used, brief self-reported physical health status measures are responsive to intervening illness among relatively healthy seniors supporting their use in longitudinal geriatric research.