Depression as a determinant of pain severity and functional limitation in patients with knee osteoarthritis: a cross-sectional study

Background: Knee osteoarthritis (OA) is a leading cause of chronic pain and disability worldwide. Psychosocial factors especially depression-could greatly affect pain perception and functional outcomes in people who are affected. Objectives were to assess the prevalence of depressive symptoms and their relationship with pain severity and functional limitation in knee OA patients. Methods: This is a hospital-based cross-sectional study that included 110 adult patients with primary knee OA diagnosed according to American College of Rheumatology Criteria. Depressive symptoms were assessed by the patient health questionnaire-9 (PHQ-9). A cut-off score of ≥10 was considered clinically significant depression. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) assessed pain intensity and physical function. Continuous variables were summarized as mean±SD. Group comparisons were performed with independent t tests and correlations assessed using Spearman’s coefficient. Results: The prevalence of clinically significant depressive symptoms was 20.9%. Patients with depression had mean WOMAC pain (19.2±8.1 vs 17.1±7.4; p=0·001) and function (67.5±22·5 vs 62.1±21·4; p<0·001) scores significantly higher than non-depressed patients. There was a positive correlation between PHQ-9 scores and WOMAC pain (r=0.33, p=0·002). PHQ-9 scores correlated positively also to function (r=0.41, p<0 ·001). A stepwise increase in pain and disability was observed according to the severity of depression. Conclusions: Depressive symptoms are common for knee OA patients and significantly associated with high pain intensity level and functional limitation. Routine psychological screening can be performed using validated tools such as the PHQ-9, which may improve comprehensive management of OA.