Proposed Metrics for the Determination of Rheumatoid Arthritis Outcome and Treatment Success and Failure

Abstract

Patients with rheumatoid arthritis (RA) and their physicians often disagree as to the success of RA treatment or RA outcomes. However, guidelines (such as EULAR criteria for DAS scores) are heavily weighted toward joint counts and laboratory tests, and no guidelines exist for patient reported outcomes. Our aims were (1) to provide a patient-based definition of successful RA outcome or of treatment success and failure; (2) to describe the characteristics of patients meeting this definition; (3) to describe how external states such as disability and comorbidity influence definitions of health outcome; and (4) to derive surrogate-measure cutpoints for the definition. A total of 20,268 patients with RA (5132 without comorbidity) were studied by recursive partitioning and regression methods to determine best dividing points between RA treatment and outcome success and non-success using 0-10 visual analog scales (VAS) for patient global assessment, pain, fatigue, and RA activity, and a Health Assessment Questionnaire (HAQ) scale. 14.5% of all patients and 22.9% of those without comorbidity were very satisfied with their health (success). Patient global at a level<or=1.25 best separated success from failure. Mean and median scores for those who were very satisfied were HAQ (0-3 scale) 0.36, 0.12; pain (0-10) 1.1, 0.5; global (0-10) 0.9, 0.5; and fatigue (0-10) 1.5, 1.0. VAS scores increased by approximately 0.5 units for each comorbid condition. Patient global at a level<or=1.25 best separates patients who are very satisfied with their health from those not very satisfied, regardless of the presence of comorbidity. All scores increase with increasing comorbidity, which must be accounted for when assessing individual patients. Values identified here suggest patients require better outcomes than are found in patients who are in Disease Activity Score-28 remission or OMERACT low disease activity states.