Adaptation of the WOMAC for Use in a Patient Preference Study.

Area of Science:

• Health Economics and Outcomes Research
• Clinical Trial Design
• Patient-Reported Outcomes

Background:

• Discrete Choice Experiments (DCEs) are valuable for understanding patient preferences in healthcare.
• Adapting existing Patient-Reported Outcome (PRO) measures for DCEs can enhance the relevance of clinical trial endpoints.
• The Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) is a widely used PRO for osteoarthritis.

Purpose of the Study:

• To adapt the WOMAC PRO measure into efficacy attributes for a DCE survey.
• To quantify the relative importance of commonly used endpoints in knee osteoarthritis (KOA) clinical trials.
• To assess patient comprehension and trade-off abilities with the adapted attributes.

Main Methods:

• Selected WOMAC pain and function domains for adaptation into two efficacy attributes.
• Developed two versions of a DCE instrument using total domain scores and specific item scores (e.g., walking).
• Conducted pretesting with 26 KOA patients to evaluate attribute comprehension and trade-off capabilities.

Main Results:

• Both adapted WOMAC attribute versions were found meaningful and relevant for treatment decisions.
• Patients demonstrated willingness and ability to make trade-offs between pain and function improvements.
• Patients perceived pain and function improvements as interrelated despite separate evaluation.

Conclusions:

• The adaptation of PRO measures like WOMAC is feasible and valuable for patient preference studies.
• This methodology allows for the integration of clinical trial outcomes with PRO endpoints in preference research.
• Findings support the use of adapted PROs in DCEs to better inform KOA trial endpoint selection.