A development dataset (104 patients) was explored with forward-selection linear regression analysis to choose a reduced item set for the new scale. This was tested in a validation dataset (1,833 patients) and responsiveness subset (80 patients) to measure agreement between the shorter and longer versions and to test the sensitivity of the shorter instrument to change after treatment.
Twelve items were chosen for a short version of the International Hip Outcome Tool (iHOT-12). The iHOT-12 showed excellent agreement with the long version (iHOT-33). It captured 95.9 % (95 % confidence interval, 95.0 % to 96.8 % ) of the variation of the iHOT-33 and showed equivalent sensitivity to change with a standardized effect size of 0.98 (95 % confidence interval, 0.67 to 1.28).
A short version of the International Hip Outcome Tool (iHOT-12) has been developed. It has very similar characteristics to the original rigorously validated 33-item questionnaire, losing very little information despite being only one-third the length. It is valid, reliable, and responsive to change. We suggest that it be used for initial assessment and postoperative follow-up in routine clinical practice.