Do psychological factors predict response to intra-articular steroid therapy in knee osteoarthritis?

Purpose: Intra-articular steroid therapy is widely used in clinical practice in the management of knee osteoarthritis (OA) and included in current management guidelines for the disease. There is a paucity of data, however, about the influence of psychological factors on treatment response. Such data are important and may help better targeting of therapy. The aim of this analysis was to determine whether levels of anxiety and depression at baseline influence response to intra-articular steroid therapy in patients with symptomatic knee OA.
Methods: Men and women aged 40 years and older with painful knee OA, and who met American College of Rheumatology (ACR) criteria for the disease, were recruited for participation in an ongoing open-label clinical trial of intra-articular steroid therapy. Subjects who took part in the study had significant knee pain and had grade 2 (Kellgren-Lawrence) or higher knee OA. At baseline they completed questionnaires about their symptoms including the Knee Injury and Osteoarthritis Outcome Score (KOOS) (0-100), with lower scores indicating greater pain and also a VAS (0–10) for pain during a nominated activity (VASnA), with higher scores indicating greater pain. They also completed the Hospital Anxiety and Depression (HAD) Scale, a 14-item scale which includes items relating to anxiety and depression both ranging in total from 0 (none) to 21 (maximum). They subsequently had an intra-articular steroid injection with repeat pain assessments at the follow-up visit usually within a 2 week period. We used linear regression to look whether pre-intervention anxiety and depression scores were associated with change in pain. We also used between-groups t-tests to investigate whether these scores differed between responders and non-responders (according to OARSI-OMERACT criteria).
Results: Eighty-eight patients, mean age 61.2 yrs (SD = 10.2 yrs), of whom 48 (54.6%) were female, were studied. The median time between the baseline and follow-up assessment was 8 days (inter-quartile range 7–13 days). There was an increase in KOOS score between baseline and follow-up (25.2 points; 95% Confidence Interval [CI] 20.5–30.0 points; p < 0.001) and a reduction in VASnA (−3.3 cm; 95% CI −3.9 to −2.6 cm; p < 0.001), both indicating an improvement in pain symptoms following steroid injection. Higher anxiety scores at baseline were associated with less change in pain (following intervention) using KOOS (b coefficient / per unit change in anxiety score = −1.08; 95% CI −2.16 to −0.01; p = 0.049). Higher anxiety levels were weakly positively linked with change in pain using VASnA (b coefficient = 0.06; 95% CI −0.09–0.22; p = 0.44) though the confidence intervals included zero. Higher depression scores at baseline were not associated with a change in pain using KOOS (b coefficient = −1.07; 95% CI −2.34–0.21; p = 0.10) or change in pain using VASnA (b coefficient = 0.04; 95% CI −0.14–0.22; p = 0.63). Using the OARSI-OMERACT criteria 62 (70.5%) patients were responders. Those who responded had lower anxiety scores than those who did not respond (mean score = 5.96 vs 7.43; p = 0.15) and lower depression scores (mean score = 4.16 vs 4.64; p = 0.18); however, these differences were not statistically significant.
Conclusion: Adverse psychological factors, especially anxiety, appear to limit response to intra-articular steroid treatment in patients with symptomatic knee OA.