Model 1 - Hierarchical logistic regression analysis of Moderate to Severe Persistent Post-surgical Pain 4–6 months (T3) following TKA and THA on clinical and psychological measures at baseline (T1).

<p>Note. After removing 2 outliers, this final model correctly predicted 74% of all patients; <i>χ2</i>(6) = 31.696; <i>p</i><0.001; Nagelkerke <i>R</i><sup>2</sup> = 0.412; OR = odds ratioCI = confidence interval; bold = significant at <i>p</i>≤.05; italics = marginally significant <i>p</i>≤.10.</p>1<p>Continuous variable, NRS - Numerical Rating Scale (0–10) from BPI-SF: Brief Pain Inventory-Short Form;</p>2<p>Continuous variable;</p>3<p>Dichotomic variable: 0 = THA: Total Hip Arthroplasty; 1 = TKA: Total Knee Arthroplasty;</p>a<p>Continuous variable, HADS-A: Hospital Anxiety and Depression Scale - anxiety subscale;</p>b<p>Continuous variables, subscales of IPQ-R: Illness Perception Questionnaire Revised.</p>