Evaluation of Dynamic Effects of Depressive Symptoms on Physical Function in Knee Osteoarthritis
This article was prepared using an OAI public use data set and does not necessarily reflect the opinions or views of the OAI investigators, the NIH, or the private funding partners.
Supported by grants from the National Institute on Aging/NIH (grants P30-AG-028747, K01-AG-064041, and T32-AG-000262), the Rheumatology Research Foundation Graduate Student Achievement Award, and the Senior Research Career Scientist Award (grant IK6-RX-003977) from the United States Department of Veterans Affairs Rehabilitation R&D Service for Dr Ryan. The Osteoarthritis Initiative (OAI) is a public-private partnership composed of five contracts (N01-AR2-2258, N01-AR-22259, N01-AR-22260, N01-AR-22261, and N01-AR-22262) funded by the NIH. Private funding partners include Merck Research Laboratories, Novartis Pharmaceuticals Corporation, GlaxoSmithKline, and Pfizer, Inc. Private sector funding for the OAI is managed by the Foundation for the NIH.
Additional supplementary information cited in this article can be found online in the Supporting Information section (http://onlinelibrary.wiley.com/doi/10.1002/acr.25295).
Author disclosures are available at https://onlinelibrary.wiley.com/doi/10.1002/acr.25295.
Abstract
Objective
To assess how changes in depressive symptoms influence physical function over time among those with radiographic knee osteoarthritis (OA).
Methods
Participants from the Osteoarthritis Initiative with radiographic knee OA (n = 2,212) and complete data were identified at baseline. Depressive symptoms were assessed as a time-varying score at baseline and the first three annual follow-up visits using the Center for Epidemiological Studies Depression Scale (CES-D) Scale. Physical function was measured at the first four follow-up visits using 20-meter gait speed meters per second. The following two marginal structural models were fit: one assessing the main effect of depressive symptoms on gait speed and another assessing time-specific associations.
Results
Time-adjusted results indicated that higher CES-D scores were significantly associated with slower gait speed (−0.0048; 95% confidence interval −0.0082 to −0.0014), and time-specific associations of CES-D were largest during the first follow-up interval (−0.0082; 95% confidence interval −0.0128 to −0.0035). During subsequent follow-up time points, the influence of depressive symptoms on gait speed diminished.
Conclusion
The negative effect of depressive symptoms on physical function may decrease over time as knee OA progresses.