Abstract
Background
The Timed Up and Go (TUG) test is frequently used to assess patients' functional mobility.
However, its psychometric characteristics in patients with haemophilia (PwH) are unknown.
This study's primary aim was to determine the validity, reliability, standard error
of measurement (SEM), and minimal detectable change (MDC) of the TUG in PwH. The secondary
aim was to determine predictors for the TUG time.
Methods
A total of 40 PwH were included. Test-retest reliability was assessed by the same
rater at two time points and inter-rater reliability was assessed by two raters. Construct
validity was tested via correlation analyses between the TUG and the haemophilia joint
health score (HJHS), the short physical performance battery (SPPB), the HEP-Test-questionnaire,
and the Haemophilia Activity List (HAL). SEM and MDC were calculated. Multiple linear
regression analyses with several patient-specific predictors were performed.
Results
Test-retest and inter-rater reliability analyses revealed excellent ICCs of 0.990
(95% CI: 0.972–0.995) and 0.929 (95% CI: 0.870–0.962), respectively. The SEM and MDC
of the TUG were 0.34 and 1.52 seconds, respectively. Large correlations (r > 0.5) were observed between the TUG and the HJHS, SPPB, HEP-Test-Q, and HAL. Regression
analysis revealed the HJHS as the sole significant predictor, with the full model
explaining 37.0% of the variance in TUG performance.
Conclusion
In PwH, the TUG is a reliable test possessing an excellent test-retest and inter-rater
reliability, while showing a high validity. TUG times can mainly be predicted by HJHS.
The TUG can therefore be considered a suitable tool to evaluate mobility in adult
PwH.
Keywords
rare disease - functional mobility - motor performance - physical testing
