AB1324 MEASUREMENT PROPERTIES OF THE 10-ITEM CONNOR-DAVIDSON RESILIENCE SCALE AMONG PATIENTS WITH TOTAL KNEE REPLACEMENT BASED ON ITEM RESPONSE THEORY
Authors: Ka Keat Lim, Yu Heng Kwan, Seng Jin Yeo, William Yeo, Julian Thumboo, David Matchar, Ying Ying Leung
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> The number of older adults undergoing total knee arthroplasty (TKR) for knee osteoarthritis (OA) has been increasing. While psychological resilience may have a role in outcomes after TKR[1], no psychological resilience scale has been validated among patients with knee OA. <h3>Objectives</h3> To examine the measurement properties of the 10-item Connor-Davidson Resilience Scale (CD-RISC10) among older adults with knee OA. <h3>Methods</h3> Using data from 700 consecutive consented patients with knee OA enlisted for TKR, we examined four measurement properties of CD-RISC10. For <b>structural validity</b>, we fitted graded response model (grm) and examined standardized root-mean square residual (SRMR) for unidimensionality, Chi-square p-value for item fit, residual correlation for local independence and item-characteristic curves for monotonicity. For <b>internal consistency</b>, we examined Cronbach's alpha. For <b>construct validity</b>, we hypothesized that CD-RISC10 as a measure of psychological resilience would be moderately correlated (Pearson's R 0.30–0.50) with self-efficacy and mental well-being but weakly correlated (Pearson's R&lt;0.30) with physical and social well-being (Table 1). For <b>measurement invariance</b>, we examined uniform and non-uniform differential item functioning (DIF) between gender, age group (≤ median 66 vs &gt;66 years), and language (English vs Chinese) and reported the McFadden's R<sup>2</sup>. We used mirt and lordif packages on Rx64 v3.5.1 to examine grm and DIF respectively. We reported the findings based on COnsensus based Standards for the selection of health Measurement Instruments (COSMIN)[2]. <h3>Results</h3> Of the 700 patients (age 65.5±6.9 years old), 70.6% were females, 83.9% Chinese, 55% responded questionnaire in Chinese. Mean CD-RISC10 score was 27.5±5.2, with minimal floor (0.1%) and ceiling effects (3.9%). CD-RISC10 demonstrated unidimensionality (SRMR=0.053), local independence (residual correlation=-0.025), monotonicity (adequate looking item characteristic curves) and internal consistency (Cronbach's alpha=0.91). Items 1 and 4 had potential misfit (Chi-square p&gt;0.01). All a-priori hypotheses were met (Table 1). No item had significant DIF with age, gender and language, except item 4 had borderline non-uniform DIF across language (McFadden's R<sup>2</sup>=0.03). <h3>Conclusion</h3> We demonstrated structure validity, internal consistency, construct validity and measurement invariance of CD-RISC10 in the measurement of psychological resilience among older adults with knee OA. <h3>References</h3> [1] Rebagliati, et al. Funct Neurol, 2016. 31(3): 171-7. [2] Mokkink, et al. COSMIN User Manual. 2018 <h3>Disclosure of Interests</h3> Ka Keat Lim: None declared, Yu Heng Kwan: None declared, Seng Jin Yeo: None declared, William Yeo: None declared, Julian Thumboo: None declared, David Matchar: None declared, Ying Ying Leung Grant/research support from: Abbvie, Novartis, Speakers bureau: Abbvie and Novartis, Speakers bureau: Novartis