Prevalence of sustained remission in rheumatoid arthritis: impact of criteria sets and disease duration, a Nationwide Study in Sweden

Objectives The aims of this national study in Sweden of patients with RA were to: examine the prevalence of sustained remission (SR), that is, remission lasting for at least 6 months; compare the prevalence of SR in patients with early RA and established RA; study the timing of onset of and time spent in SR; and study possible predictors of SR. Methods Adult patients with RA included in the Swedish Rheumatology Quality registry were studied. The registry was searched for patients fulfilling remission criteria: DAS28-ESR, Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI) and ACR/EULAR remission for at least 6 months. Early RA was defined as symptom duration ⩽6 months at inclusion in the Swedish Rheumatology Quality. Results Of 29 084 patients, 12 193 (41.9%) reached DAS28 SR at some time point during follow-up compared with 6445 (22.2%), 6199 (21.3%) and 5087 (17.5%) for CDAI, SDAI and ACR/EULAR SR, respectively. SR was more common in early RA (P < 0.001). The median time from symptom onset to SR was 1.9, 2.4, 2.4 and 2.5 years according to DAS28, CDAI, SDAI and ACR/EULAR criteria, respectively. Lower age, male sex and milder disease characteristics were associated with SR. Conclusion The majority of patients in this nationwide study never reached SR. Patients with early RA are more likely to reach SR than patients with established RA.