Skip to main content
. Author manuscript; available in PMC: 2019 Feb 1.
Published in final edited form as: J Rheumatol. 2018 May 1;45(9):1308–1315. doi: 10.3899/jrheum.170928

Table 1. 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 Number of rescue medication pills/week
Composite 1: WOMAC pain & number of rescue medication pills 1.32 65.86% 0.81 0.81
Composite 2: WOMAC Pain, Stiffness, & Function 2.85 95.03% 0.98 0.98 0.96
Composite 3: WOMAC Pain, Stiffness, & Function, & number of rescue medication pills 2.99 74.77% 0.97 0.97 0.95 0.45

Greyed-out cells indicate that the variable was not used when generating the composite. For example, composite 1 used a principal-components analysis featuring the WOMAC pain subscale score and number of rescue medication pills only. In all principal components models, the first component produced was used as the composite outcome.