Figure 1From: Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity scoreContribution of individual variables to composite scores. Explanation of score variability for (a) the Simplified Disease Activity Index (SDAI), (b) the Disease Activity Score (DAS)28, and (c) the DAS28-CRP for the respective clinical and acute phase reactant (APR) variables, at zero-order (i.e. R2 if the variable was introduced as the first one; black bars) or finally (i.e. R2 if variable was introduced in the model as the last one; grey bars), and item colinearity within the respective composite index (1 - tolerance, expressed as percentage; white bars; n = 767). CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; PGA/EGA, patient/evaluator global assessment of disease activity (100 mm visual analogue scale); TJC/SJC, tender/swollen joint count (28 joints).Back to article page