Improved flare and remission pattern in rheumatoid arthritis over recent decades: a population-based study

Objective. To assess trends in the occurrence of flares and remission in RA over recent decades. Methods. A retrospective medical records review of each clinical visit was performed in a population-based cohort of patients with RA (age >= 30 years; 1987 ACR criteria met in 1988-2007) to estimate flare and remission status. RA flare was defined as any worsening of RA activity leading to an initiation, change or increase of therapy (OMERACT 9). The primary definition for remission required the absence of RA disease activity (i.e. tender joint count 0, swollen joint count 0 and ESR <= 10 mm/h) (OMERACT 7). All subjects were followed until death, migration or 1 July 2012. Results. The study included 650 RA patients (mean age 55.8 years; 69% female) with a mean follow up of 10.3 years. Patients were flaring at 2887 (17%) visits. There was a significant decline in the RA flare rate across disease duration (P < 0.001), predominantly in the first 5 years after diagnosis of RA. Patients diagnosed with RA in more recent years experienced fewer flares during first few years of RA (P< 0.001). There was no difference between the sexes in trends of flare rates over time (P = 0.42) Current smokers had higher flare rates than non-smokers (P = 0.047) and former smokers were not different from non-smokers (P = 0.87). Conclusion. Patients diagnosed in more recent years have lower flare rates than those diagnosed in prior decades. Flare rates declined fastest in the first 5 years of disease and tended to be stable thereafter. Current smoking was associated with an adverse flare profile.