Translation, validation and test-retest reliability of the VISA-G patient-reported outcome tool into Danish (VISA-G.DK).

The Victorian Institute of Sport Assessment (VISA) questionnaire model is based on item response theory using a graded response (responses reflect increasing difficulty). The purpose of the VISA-G is to monitor patient outcomes and evaluate treatment strategies for people with greater trochanteric pain syndrome (GTPS). The primary aim of the current study was to translate and culturally adapt the VISA-G into a Danish context (DK) through forward and back translation and cognitive interviews. The second aim was to establish test-retest reliability and face validity of the VISA-G into a Danish context (DK). No major disagreements were observed between the original and translated versions of the questionnaire. A total of 58 heterogenous asymptomatic, and 49 symptomatic respondents (response rate: 92% and 78% respectively) completed the VISA-G.DK twice, 1 week apart. The VISA-G.DK had excellent internal consistency (Cronbach's alpha: asymptomatic = 0.86; symptomatic = 0.98). The test-retest reliability was excellent for the total score: ICC: 0.961 (95% CI [0.933-0.978]). Standard Error Measurement was calculated to be 0.6. Bland-Altman plots showed no significant or relevant differences from test to retest in the total score with mean differences below 1 (0.61). The minimal detectable change was 3.17 for both groups. The VISA-G.DK was found to be valid, reliable and acceptable for use in the Danish population.