Effect of age at rheumatoid arthritis onset on clinical, radiographic, and functional outcomes: The ESPOIR cohort.

Objectives: To investigate whether age at disease onset determines clinical, radiographic or functional outcomes in a cohort of early RA.

Methods: The ESPOIR cohort is a multicenter cohort of patients with early arthritis. We selected patients fulfilling the 2010 ACR/EULAR criteria for RA during the first 3years of follow-up. Patients were pooled into 3 groups by age at RA onset: <45years (young-onset RA [YORA]), 45 to 60years (intermediate-onset RA [IORA]) and>60years (late-onset RA [LORA]). The following outcomes were compared at baseline and during the first 3years of follow-up: Simple Disease Activity Index (SDAI) remission rate, one additional erosion, Health Assessment Questionnaire Disability Index (HAQ-DI)<0.5 and first disease-modifying anti-rheumatic drug (DMARD) continuation rate.

Results: We included 698 patients (median [interquartile range] age 50.3 [39.8-57.2]years), 266 YORA, 314 IORA, and 118 LORA. At 1year, SDAI remission was greater for YORA than IORA and LORA (P<0.0001). Having at least one additional erosion was greater for LORA and IORA than YORA after 1year (P=0.009) and 3years (P=0.017). The proportion of patients with HAQ score<0.5 was greater for YORA than IORA and LORA at 1 (P=0.007), 2 and 3years. First DMARD continuation rate was lower for YORA than other groups during the 3years (P=0.005).

Conclusions: In a cohort of early RA, young age at disease onset is associated with high rate of remission at 1year, no radiographic progression at 3years and low functional score during 3-year follow-up.