Test-retest reliability and minimal detectable change of four functional tests in community-dwelling older adults with high risk of falls.

Objectives: This study aimed to quantify test-retest reliability and minimal detectable change (MDC) of the four commonly used functional tests in older adults with a high risk of falling.

Patients and methods: The cross-sectional study was conducted with 30 community-dwelling older adults (26 females, 4 males; mean age: 73.7±6.0 years; range, 65 to 88 years) with a high fall risk identified by the Thai falls risk assessment test between November 2018 and May 2019. Data from the 10-m walk test at a comfortable gait speed (CGS) and fast gait speed (FGS), timed up and go (TUG) test, five times sit to stand test (FTSST), and 6-min walk test (6MWT) were collected twice for each participant. The interval between test sessions was one week. Test-retest reliability was analyzed by the intraclass correlation coefficient (ICC). Standard error of measurement (SEM) and MDC at the 95% confidence interval (MDC₉₅) were also calculated.

Results: The four functional tests had ICC in the range of 0.92 to 0.97. The SEM values of the CGS, FGS, TUG, FTSST, and 6MWT were 0.06 m/sec, 0.04 m/sec, 1.10 sec, 1.30 sec, and 20.60 m, respectively. The MDC₉₅ values of the CGS, FGS, TUG, FTSST, and 6MWT were 0.16 m/sec, 0.12 m/sec, 3.00 sec, 3.50 sec, and 57.20 m, respectively.

Conclusion: All functional tests demonstrated excellent test-retest reliability. The SEM and MDC₉₅ of all functional tests were established. These findings can help clinicians interpret the effectiveness of interventions and determine changes in functional ability over time in older adults at high risk of falls.