Many self-report tools that measure function and disability are not sensitive to small changes or have a ceiling effect in populations with diverse activity competencies, like patients with cardiovascular disease (CVD). To address this measurement limitation, the Late Life Function and Disability Instrument (LLFDI) was developed and tested for use as an interview-based outcome measure in community-dwelling older adults. The purpose of this study was to determine if the LLFDI could be administered via self-report instead of by interview in patients with CVD.

The Functional Component of the LLFDI has 32 items that rate task difficulty and the Disability Component of the LLFDI has 16 items that rate task difficulty and frequency on a 5-point ordinal scale. Subjects (n = 29) were patients over 60 years old with CVD participating in an outpatient cardiac rehabilitation program. We collected data, using the LLFDI in a self-report format and again using an interview format 1-5 days later. We used descriptive statistics, correlations, and t tests to analyze the data (P< .05). All LLFDI component scores obtained via self-report were significantly correlated (r = 0.77-0.95) with scores obtained via interview. There was no significant difference between LLFDI scores obtained through patient self-report and those obtained through interview. The LLFDI did not demonstrate a floor effect and only the Disability Component difficulty scale of the LLFDI had a ceiling effect in 10% of study participants.

The results of this study show that LLFDI scores obtained via self-report have a strong relationship with LLFDI scores obtained via interview. These findings suggest that this instrument can be independently completed by patients with CVD rather than administered by clinicians. Self-report administration of the LLFDI makes it more feasible to use in cardiac rehabilitation settings. In addition, the LLFDI demonstrated minimal floor/ceiling effects in patients with CVD, making it a useful functional outcome measure in this population. The LLFDI should be considered a viable outcome measurement choice for patients with CVD because it can be administered via self-report and provides a sensitive measure of function and disability.