Psychological factors associated with instrumental activities of daily living disability in older adults with moderate to severe knee osteoarthritis

BACKGROUND: The population of older adults with knee osteoarthritis (OA)-related disabilities is increasing globally. However, studies regarding instrumental activities of daily living (IADL) in older adults with knee OA are limited. OBJECTIVE: This study investigated the psychological factors associated with IADL disability in older adults with moderate to severe knee OA. METHODS: A cross-sectional study was conducted on 179 patients with knee OA aged > 65 years. The six-item short form of the Pain Catastrophizing Scale (PCS-6), the four-item short form of the Pain Self-Efficacy Questionnaire (PSEQ-4), and the fifteen-item Geriatric Depression Scale (GDS-15) were used to assess psychological factors. The participants were divided into IADL disabled and non-disabled groups. Binary logistic regression analyses were performed with the IADL disability status as the dependent variable. The PCS-6, PSEQ-4, and GDS-15 tools were included as independent variables in the logistic regression model. RESULTS: Of the 179 participants, 88 (49.1%) showed disability in conducting IADL. PSEQ-4 (odds ratio = 0.90, 95%; confidence interval = 0.82-0.99, p = 0.02) was a significant independent variable among all psychological factors. CONCLUSION: Even after controlling for cofounders, our study found that self-efficacy, assessed using the PSEQ-4, was related to IADL disability in older adults with moderate to severe knee OA.