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Dynamic Effects of Depressive Symptoms on Osteoarthritis Knee Pain
Author(s) -
Rathbun Alan M.,
Stuart Elizabeth A.,
Shardell Michelle,
Yau Michelle S.,
Baumgarten Mona,
Hochberg Marc C.
Publication year - 2018
Publication title -
arthritis care and research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.032
H-Index - 163
eISSN - 2151-4658
pISSN - 2151-464X
DOI - 10.1002/acr.23239
Subject(s) - womac , osteoarthritis , medicine , physical therapy , depression (economics) , confidence interval , knee pain , depressive symptoms , psychiatry , cognition , alternative medicine , pathology , economics , macroeconomics
Objective To estimate the dynamic causal effects of depressive symptoms on osteoarthritis ( OA ) knee pain. Methods Marginal structural models were used to examine dynamic associations between depressive symptoms and pain over 48 months among older adults (n = 2,287) with radiographic knee OA (Kellgren/Lawrence grade 2 or 3) in the Osteoarthritis Initiative. Depressive symptoms at each annual visit were assessed (threshold ≥16) using the Center for Epidemiologic Studies Depression Scale. OA knee pain was measured using the Western Ontario and McMaster Universities Osteoarthritis Index ( WOMAC ) pain subscale, rescaled to range from 0 to 100. Results Depressive symptoms at each visit were generally not associated with greater OA knee pain at subsequent time points. Causal mean differences in WOMAC pain score comparing depressed to nondepressed patients ranged from 1.78 (95% confidence interval [95% CI ] −0.73, 4.30) to 2.58 (95% CI 0.23, 4.93) within the first and fourth years, and the depressive symptoms by time interaction were not statistically significant ( P = 0.94). However, there was a statistically significant dose‐response relationship between the persistence of depressive symptoms and OA knee pain severity ( P = 0.002). Causal mean differences in WOMAC pain score comparing depressed to nondepressed patients were 0.89 (95% CI −0.17, 1.96) for 1 visit with depressive symptoms, 2.35 (95% CI 0.64, 4.06) for 2 visits with depressive symptoms, and 3.57 (95% CI 0.43, 6.71) for 3 visits with depressive symptoms. Conclusion The causal effect of depressive symptoms on OA knee pain does not change over time, but pain severity significantly increases with the persistence of depressed mood.