Rheumatoid arthritis (RA) activity can be assessed by several outcome measures. The importance of patient-reported outcomes (PROs) has recently been advocated. Our objective was to determine whether patient self-assessment can reflect RA disease activity.
Data from patients included in the early arthritis ESPOIR cohort and fulfilling 2010 ACR/EULAR criteria for RA at month 12 were used. Data for several PROs (visual analogue scale for fatigue, pain, patient assessment of disease activity; Health Assessment Questionnaire [HAQ]; Medical Outcomes Study Short Form 36 [SF36]; Echelle de Mesure de l'Impact de la polyarthrite Rhumatoïde-court [EMIR-court] and Routine Assessment of Patient Index Data 3 [RAPID3]) were collected and their association with disease activity measured by Disease Activity Score in 28 joints-3 variables (DAS28-3v) was assessed. The association of PROs and disease activity was assessed by explained variance, Pearson correlation and performance of each PRO in differentiating low versus high disease activity states.
We evaluated data for 677 patients. Whatever the disease activity, less impaired PROs was associated with the lowest disease activity. All PROs were moderately correlated with RA disease activity. The RAPID3 had the best association with DAS28-3v in determining RA disease activity state (r=0.45-0.55, explained variance 30-45%, sensitivity 69-100% and specificity 55-78%). Global PROs (RAPID3, EMIR-court) had the highest association with disease activity, followed by PROs assessing physical function.
The association of PROs and RA disease activity (DAS28-3v) remains moderate. RAPID3, a global PRO, had the best association with disease activity as compared with other analysed PROs.