Background: We sought to investigate the reported association between depression and severity of knee osteoarthritis symptoms stratified by radiographic severity of osteoarthritis and to quantify the contribution made by depression to symptom severity.
Methods: Six hundred and sixty elderly Koreans (sixty-five years or older) were evaluated for radiographic severity of knee osteoarthritis on the basis of the Kellgren-Lawrence grading system and also for symptom severity on the basis of the Western Ontario and McMaster Universities Osteoarthritis Index scales. Patient interviews and a questionnaire that made use of a geriatric depression scale were conducted for the purpose of assessing depressive disorders. Regression analyses were performed to assess the relative contributions by radiographic severity and depression severity to Western Ontario and McMaster Universities Osteoarthritis Index scores and to explore any associations between radiographic severity and the presence of a depressive disorder with regard to the risk of symptomatic knee osteoarthritis. Symptomatic knee osteoarthritis was defined as a Western Ontario and McMaster Universities Osteoarthritis Index score of ≥39.
Results: The presence of a depressive disorder was found to be associated with an increased risk of symptomatic knee osteoarthritis (odds ratio = 5.87 [95% confidence interval, 3.01 to 11.44]). However, the influence of the presence of a depressive disorder was limited to subjects with a radiographic severity of minimal to moderate (Kellgren-Lawrence grade 0 to 3). The presence of a depressive disorder was not associated with the risk of symptomatic knee osteoarthritis in subjects with severe osteoarthritis (Kellgren-Lawrence grade 4).
Conclusions: This study indicates that the assessment and management of coexisting depression should be integrated with the assessment and management of knee osteoarthritis, particularly when radiographic changes of osteoarthritis in the knee joint are not severe.