Personal impact of disability in osteoarthritis: patient, professional and public values

Background: Osteoarthritis (OA) is a leading cause of disability. Numerous tools are available to assess this, but they fail to place a patient value upon disability. In rheumatoid arthritis, research has shown patients have different importance values for similar disabilities, and these individual values can be used to weight disability levels, creating a measure of personal impact. Objectives: Firstly, to determine if the Health Assessment Questionnaire (HAQ) can be used as the basis for an importance value scale by assessing if it includes activities considered important by OA patients. Secondly, to determine if the weights used for the value scale should be based on population, healthcare professional or patient values. Method: Twenty-five OA patients, 25 healthy controls and 25 healthcare professionals rated the importance of the items on the HAQ and shortened Modified HAQ (MHAQ). Prior to completing the HAQ, patients generated a list of activities that were important to them. Result: The HAQ contained 69% of items that patients considered important. No items were consistently deemed unimportant by patients. There was low agreement within and between groups about the importance of the items on the HAQ and MHAQ. Conclusion: The HAQ is a suitable basis for a value scale for an OA disability impact score. Importance values for function differed for patients, healthcare professionals and the general population; therefore individual patient weightings need to be used. Further work is under way to validate a measure of the personal impact of disability in patients with lower limb OA.