Association between lower limb osteoarthritis and incidence of depressive symptoms: data from the Osteoarthritis Initiative

Background: Osteoarthritis (OA) is associated with a number of medical morbidities. Although the prevalence of depression and depressive symptoms is presumed to be high in people with OA, no prospective comparative study has analyzed its incidence. 
Objective: To determine whether OA was associated with an increased odds of developing depressive symptoms. 
Design: Longitudinal cohort study (follow-up: four years). 
Setting: Data were gathered from the North American Osteoarthritis Initiative (OAI) dataset. 
Subjects: People at higher risk developing OA. 
Methods: Osteoarthritis diagnosis was defined as the presence of OA at hand, knee, hip, back/neck or other sites at baseline. Depressive symptoms were defined using the 20-item Center for Epidemiologic Studies-Depression (cut-off 16 points) after four years. 
Results: 3,491 people without depressive symptoms at baseline were analyzed (1,506 with OA/1,985 without). Using an adjusted logistic regression analysis for 12 potential confounders, people with OA had a similar odds of depressive symptoms at follow-up compared to those without OA (Odds Ratio (OR): 1.26; 95% CI: 0.95-1.67). However, multisite OA (i.e. OA 2>sites; OR: 1.48, 95% CI 1.07-2.05) and the specific presence of hip (OR: 1.72; 95% CI: 1.08-2.73) or knee OA (OR: 1.43; 95% CI: 1.03-1.98) were associated with a greater odds of developing depressive symptoms compared to people without OA. 
Conclusions: This is the first study of longitudinal data to demonstrate people with multi-site, hip or knee OA have a greater odds of developing depressive symptoms compared to people without OA. This suggests that OA may be associated with future mental health burden.