Objectives: To evaluate the function component of the Short Form of the Late-Life Function and Disability Instrument (SF-LLFDI, German version) in geriatric inpatients and compare it with established performance-based and self-rated assessment tools.
Setting: Geriatric inpatient rehabilitation unit.
Participants: One hundred fifty-six geriatric rehabilitation inpatients (44 men, 112 women) with a mean age of 81.7 who were capable of walking at baseline.
Measurements: Weekly assessments were performed from admission until discharge (3 weeks later) using the function component of the SF-LLFDI, the Barthel Index (BI), the Falls Efficacy Scale International (FES-I), gait characteristics, the Timed Up and Go Test, and the Short Physical Performance Battery. Baseline characteristics were measured at admission. Construct validity was evaluated using Spearman correlation coefficients, internal consistency was measured using Cronbach alpha, and sensitivity to change was estimated using standardized response means.
Results: The SF-LLFDI did not show significant floor or ceiling effects. Internal consistency was good, with alpha (function component sub-scores) equal to 0.80 to 0.86. Convergent validity measures concerning performance-based scores were moderate to good, and correlations increased over time (correlation coefficient (r)=0.35-0.64). There was a high correlation with the FES-I (admission: r=0.61, discharge: r=0.76). Sensitivity to change was significant for all examined scores, with the BI outperforming all other instruments, although the SF-LLFDI showed better responsiveness than the BI regarding change characteristics over time.
Conclusion: The SF-LLFDI is a reliable and valid self-report instrument to measure functional status in geriatric rehabilitation inpatients. It improves the assessment of clinically relevant responsiveness. Further research is warranted to improve its sensitivity to change.