Measurement of change in function and disability in osteoarthritis: current approaches and future challenges.

PURPOSE OF REVIEW: This review assessed current approaches to using objective and self-report measures to determine change in function and disability in osteoarthritis and identified key future challenges. RECENT
FINDINGS: New approaches to measuring function continue to evolve. However, trials and observational studies typically adopt conventional self-report instruments of physical function as their primary outcome. A range of objective measures are also used, but this area, in particular, may benefit from greater standardization. In recognition of the wider impact of osteoarthritis, there have been some moves towards measuring participation in areas of life such as social activities and work. Approaches to take more account of areas of function and extent of change perceived by the patient to be important are increasing but are not standardized. Follow-up of participants has tended to be short and infrequent.
SUMMARY: Measuring functional change is rightly recognized as critically important in osteoarthritis research. Key challenges that remain include capturing wider elements of disability such as ability to participate in everyday life, and in better capturing the longer, episodic nature of disability in osteoarthritis. Experience from fields outside of osteoarthritis may help advance the measurement of function in longitudinal studies of osteoarthritis and its sensible interpretation.