Pain outcome combinations used to create composites, with component loadings.
| Component Loading | ||||||
|---|---|---|---|---|---|---|
| Composite Outcome | Component Eigenvalue | Proportion of Variance Explained by Component | WOMAC Pain | WOMAC Stiffness | WOMAC Function | No. Rescue Medication Pills/week |
| Composite 1: WOMAC pain and no. rescue medication pills | 1.32 | 65.86% | 0.81 | — | — | 0.81 |
| Composite 2: WOMAC pain, stiffness, and function | 2.85 | 95.03% | 0.98 | 0.98 | 0.96 | — |
| Composite 3: WOMAC pain, stiffness, and function, and no. rescue medication pills | 2.99 | 74.77% | 0.97 | 0.97 | 0.95 | 0.45 |
Empty spaces indicate that the variable was not used when generating the composite. For example, composite 1 used a principal-components analysis featuring only the WOMAC pain subscale score and number of rescue medication pills. In all principal components models, the first component produced was used as the composite outcome. WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index.