Validity and Reliability of the Dutch Version of the International Hip Outcome Tool (iHOT-12NL) in Patients With Disorders of the Hip.

STUDY

DESIGN

Clinical measurement.

OBJECTIVES

To translate and culturally adapt the international Hip Outcome Tool (iHOT-12) into Dutch and to determine its validity and reliability.

BACKGROUND

The iHOT-12 for measuring health-related quality of life and physical functioning in younger, active patients with hip pathology is available in English and Swedish. The tool is scored on a 0-to-100-point scale, with higher scores reflecting better function. A Dutch version of the questionnaire, with demonstrated high validity and reliability, is needed for both clinical and research purposes.

METHODS

The iHOT-12 was translated and culturally adapted from English into Dutch (iHOT-12NL). Subsequently, the iHOT-12NL, RAND 36-Item Health Survey, Hip disability and Osteoarthritis Outcome Score (HOOS), and Tegner activity scale were completed by 117 patients with hip pathologies. Structural validity was analyzed using exploratory principal-component factor analysis. To determine construct validity, 12 hypotheses were predefined regarding relationships between the iHOT-12NL and subscales of the RAND 36-Item Health Survey, Hip disability and Osteoarthritis Outcome Score, and Tegner activity scale. To determine test-retest reliability, 61 patients completed the iHOT-12NL on a second occasion within a 2-week period. Intraclass correlation coefficient (ICC), Cronbach alpha, standard error of measurement (SEM), and minimal detectable change (MDC) were calculated to assess reliability. Bland-Altman analysis was conducted to assess bias between test and retest.

RESULTS

Factor analysis revealed that the iHOT-12NL has 1 component. Construct validity was good, as 83% of the hypotheses were confirmed. Internal consistency was good, with a Cronbach alpha of .96. The ICC was 0.93 (95% confidence interval: 0.88, 0.96), demonstrating good test-retest reliability. The SEM was 7.3 points. Individual- and group-level MDC values were 20.2 and 2.6 points, respectively. Bland-Altman analysis showed an absence of bias.

CONCLUSION

The iHOT-12NL is a reliable and valid instrument for measuring physical functioning and health-related quality of life in younger, physically active patients with hip pathology.