Abstract
Objective This paper's purpose was to assess the reliability, measurement error, construct
validity, and responsiveness of the Spanish version of the QuickDASH for outcomes
assessment in Carpal Tunnel Syndrome (CTS).
Methods A total population of 40 patients was diagnosed with CTS. The Spanish versions of
the QuickDASH, CTS-AL, and EQ-5D were completed by the patients 1 week, the day before
surgery, and 3 months after the surgery. Internal consistency was analyzed by Cronbach
α coefficient. The intraclass correlation (ICC2,1 ), Lin's coefficient (CCC), and Bland and Altman Limit of Agreement (LoA) were used
for the absolute agreement assessment, and the non-parametric Passing-Bablock (P-B)
were used to assess constant and proportional systematic bias between the measurements.
Cross-sectional precision was analyzed with the Standard Error of the Measurement
(SEM). Longitudinal precision for the test-retest reliability coefficient was analyzed
with the Standard Error of the Measurement difference (SEMdiff) and the Minimal Detectable
Change at 90% (MDC90) and 95% (MDC95) confidence levels. For assessing construct validity,
we hypothesized that the QuickDASH would have a strong positive correlation with the
CTS-AL and a moderate negative correlation with the EQ-5D Index, using a Pearson correlation
coefficient (r) with a level of significance of 0.05.
Results Cronbach coefficient was 0.912. ICC2,1 and CCC showed a high absolute agreement (0.868 and 0.738 respectively). The P-B
regression showed no significant constant and proportional differences between the
two administrations of QuickDASH. The QuickDASH showed a responsiveness (ES = 2.1;
SRM = 1.97) lower than the CTS-AL (ES = 3.53; SRM = 3.50), and higher than the EQ-5D
Index (ES =0.78; SRM =0.83).
Conclusion The Spanish (Spain) version of the QuickDASH instrument presented a good level of
reliability, construct validity, and responsiveness for outcomes assessment in CTS.
Keywords reliability - validity - construction validity - QuickDASH - Carpal Tunnel Syndrome
