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Table 4 Stepwise multiple regression showing 15 predictors ranked in order of magnitude in predicting group membership (FM or RA/SLE)

From: Distinguishing fibromyalgia from rheumatoid arthritis and systemic lupus in clinical questionnaires: an analysis of the revised Fibromyalgia Impact Questionnaire (FIQR) and its variant, the Symptom Impact Questionnaire (SIQR), along with pain locations

Predictors Step and number of variables included Multiple R Multiple R2 R2 change Pvalue for predictor variable
Mid-lower back 1 0.540 0.291 0.291 0.00000
Tenderness to touch 2 0.637 0.406 0.115 0.00000
Neck 3 0.689 0.474 0.068 0.00000
Arms 4 0.712 0.507 0.033 0.00007
Hands 5 0.747 0.558 0.051 0.00000
Lateral lower back 6 0.758 0.575 0.017 0.00168
Sitting for 45 minutes 7 0.768 0.589 0.014 0.00367
Feeling overwhelmed 8 0.775 0.601 0.012 0.00750
Depression 9 0.784 0.615 0.014 0.00365
Sensitivity 10 0.791 0.626 0.011 0.00855
Thighs 11 0.797 0.635 0.009 0.01471
Feet 12 0.804 0.647 0.012 0.00529
Cleaning floors 13 0.806 0.649 0.003 0.16326
Anxiety 14 0.807 0.652 0.002 0.19893
Memory 15 0.809 0.654 0.002 0.21899
  1. Note: This forward stepwise regression analysis used 15 predictors which combined to produce a multiple R = 0.809 (last row, column 2). This accounted for 65% of variance associated with group membership (column 3). FM, fibromyalgia; RA/SLE, combined rheumatoid arthritis and systemic lupus erythematosus group.