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 total 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 Our study showed the importance of assessing self-efficacy using the PSEQ-4 in relation to IADL disability in older adults with moderate to severe knee OA.