This study assessed the utility and construct validity of a new patient global assessment of symptom change for hand osteoarthritis (OA) by examining its associations with change over time in grip strength, pinch strength, and AUStralian CANadian Osteoarthritis Hand Index (AUSCAN).
Methods
Participants (N = 531, 80% female, mean age = 68) were part of a study on the Genetics of Generalized Osteoarthritis (GOGO) and completed two assessments (average 4 years apart). At the second assessment, participants described change in their right and left hand pain, aching, and stiffness on a 15-point scale with descriptors ranging from “Great deal worse” to “Great deal better”. Linear regression models examined associations of global change scores with changes in hand strength and AUSCAN, controlling for age, gender, number of hand joints with OA, and time between assessments.
Results
Both right and left hand global assessment of change scores were significantly associated with change in AUSCAN, grip strength, and right hand pinch strength (P < 0.05), and approached significance for left hand pinch strength (P = 0.06). The strongest associations were between global change scores and AUSCAN change (right hand: β = 0.29, P < 0.001; left hand: β = 0.27, P < 0.001). Associations of change scores with grip and pinch strength were stronger among participants with greater radiographic OA severity at baseline.
Conclusion
Results support the validity of this new global assessment of symptom change. This measure is particularly useful for assessing change over time when no baseline data are available. Additional research should examine this measure's responsiveness in the context of clinical trials.
This study was supported by a grant from GlaxoSmithKline. This study was performed in part, at the Duke General Clinical Research Unit, funded by NIH MO1-RR-30, National Center for Research Resources. This study was also supported in part by a Merit Review Entry Program Award from the Department of Veterans Affairs, Veterans Health Administration, Health Services Research and Development Service to the first author.