Performance of global assessments of hip, knee, and back symptom change

The objective of this study is to compare patients' global assessments of change in knee, hip, and back symptoms with actual changes over time in pain, function, and radiographic severity. The participants (n = 894, 80% female, mean age = 66 years) completed two assessments (mean of 4 years apart) as part of a study on the genetics of generalized osteoarthritis. At both assessments, participants completed the Western Ontario and McMaster Universities OA Index (WOMAC), and radiographic severity was assessed for knees, hips, and low back. At the second assessment, participants described changes in knee, hip, and low back symptoms as worse, better, same, or never had symptoms. Analysis of covariance models examined mean changes in WOMAC scores and radiographic severity according to categories of the global assessment measures. Statistical significance was examined for linear trend. Mean WOMAC total, pain, and function scores decreased (indicating improvement) among participants who indicated joint symptoms were better, showed little change among those who reported symptoms were the same/never had symptoms, and increased among those who reported symptoms were worse. For all analyses except the comparison of WOMAC pain change according to global assessment of low back symptom change, there was a statistically significant linear trend (p < 0.05). Patterns were similar for changes in radiographic severity, but the tests of linear trend were not statistically significant. Results support the concordance of these global assessments of joint symptom change with actual changes in self-reported symptoms. These global assessments may be useful for assessing change over time when baseline data are unavailable.