A measure based on patient data provides a reasonable definition of rheumatoid arthritis (RA) outcome and RA treatment success or nonsuccess. Among patient-reported variables, patient global at a level of 1.25 or lower best separates patients who are very satisfied with their health from those not very satisfied, regardless of the presence of comorbidity.
Wolfe and Michaud used recursive partitioning and regression methods to study 20,268 patients with RA. Study variables included treatment variables; comorbidity; satisfaction with health; functional status (using a Health Assessment Questionnaire scale); and pain, global severity, and fatigue (using visual analog scales).
Among all patients, 14.5% were very satisfied with their health; among those without comorbidity, 22.9% were very satisfied. Correlations between patient health satisfaction and other measures were patient global, 0.676; physician global, 0.487; and Disease Activity Score-28, 0.464, indicating a lack of agreement. Very satisfied patients had substantially less abnormal RA activity and severity scores.
A global score of 1.25 or lower was the best predictor of RA outcome and treatment. Global severity had the best positive and negative predictive values.
The authors noted that all scores increase with increasing comorbidity and that this must be accounted for when a patient is assessed.