Long-Term Outcomes in Seronegative Rheumatoid Arthritis

The purpose of this study was to determine the cumulative incidence of diagnosis switching, drug-free remission, and initiation of a biologic or targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) in individuals with seronegative rheumatoid arthritis (RA).

Adult residents of Olmsted County, Minnesota, with incident seronegative (rheumatoid factor negative/anti-cyclic citrullinated peptide antibody negative) RA meeting the 1987 and/or 2010 American College of Rheumatology classification criteria were included. Data were collected from January 1, 2005, to December 31, 2023, through manual chart review. Drug-free remission was defined as a period of at least six months where the individual was no longer taking treatment for RA and did not have evidence of active inflammatory arthritis upon evaluation by a rheumatologist. We calculated the 10-year cumulative incidence of a change in diagnosis, adjusting for the competing risk of death, and of drug-free remission and initiation of a b/tsDMARD, adjusting for the competing risks of death or change in diagnosis.

A total of 176 individuals with seronegative RA (68% women) were included. The 10-year cumulative incidence of a change in diagnosis was 12.8% (95% confidence interval [CI] 8.7%-18.9%). The most common change in diagnosis was to spondyloarthritis (4%). The 10-year cumulative incidence of drug-free remission and initiation of a b/tsDMARD was 26.6% (95% CI 20.7%-34.2%) and 19.9% (95% CI 14.7%-26.9%), respectively. Over a median follow-up of 11.8 years, 49 individuals entered drug-free remission.

After initial diagnosis of seronegative RA, about 13% of individuals had a change in diagnosis and a quarter experienced drug-free remission within 10 years.