Abstract
This study aimed to examine whether engagement in weekly walking moderates the relationship between frailty and depressive symptoms among patients with rheumatoid arthritis, a population known to be vulnerable to both physical and psychological decline. This cross-sectional observational study used data from the 2016 and 2018 Korea National Health and Nutrition Examination Surveys. The sample included 206 adults aged 45 years or older who were diagnosed with rheumatoid arthritis. Survey-weighted multivariable linear regression analyses accounting for the complex sampling design were employed to examine the moderating effects of walking frequency on the frailty-depression relationship. Subsequently, the conditional effect of the moderator was examined using the Johnson-Neyman technique to identify the levels of weekly walking days at which the relationship between frailty and depressive symptoms varied. Frailty emerged as a significant predictor of depressive symptoms. A significant interaction was found between frailty and walking frequency, indicating a buffering effect of walking (β = -3.68, p = 0.010). The Johnson-Neyman analysis revealed that the positive association between frailty and depressive symptoms emerged when individuals walked less than approximately 3.5 days per week. Engagement in weekly walking attenuated the relationship between frailty and depressive symptoms among patients with rheumatoid arthritis. These findings highlight the importance of promoting even low levels of physical activity, such as short walking sessions, to support mental health and reduce the risk of depression in frail patients with rheumatoid arthritis. However, the cross-sectional design, self-reported data, and lack of control for clinical factors limit causal interpretation.