MAUI, HAWAII – Viewing seronegative rheumatoid arthritis as something akin to RA-lite would be a big mistake, John J. Cush, MD, asserted at the 2020 Rheumatology Winter Clinical Symposium.
Bruce Jancin/MDedge News
Dr. John J. Cush
“It’s not a benign subtype of RA. And then again, it may not be RA,” Dr. Cush observed,
“Seronegative RA means that either you need to get serious about what is probably badass disease or you need to reevaluate whether this really is RA and your need for DMARDs [disease-modifying antirheumatic drugs] in an ongoing fashion,” the rheumatologist said. “Always reconsider whether they need less therapy or maybe no therapy at all. Maybe they had inflammation at one point and now they’re left with degenerative and mechanical changes that don’t require a DMARD or biologic.”
He highlighted a Finnish 10-year, prospective, observational study that sheds light on the subject. The study demonstrated that seronegative RA is seldom what it at first seems. The Finnish rheumatologists followed 435 consecutive patients initially diagnosed as having seronegative early RA. The structured follow-up entailed four or five interdisciplinary clinic visits within the first 2 years after diagnosis and again at 5 and 10 years.
By the 10-year mark only 4 of the 435 initially seronegative RA patients had been reclassified as having seropositive RA, while another 9 were reclassified as having erosive RA based upon the development of pathognomonic joint lesions. That’s a paltry 3% reclassification rate to classic RA.
Nearly two-thirds of patients were ultimately reclassified within 10 years as they evolved into diagnoses other than their original seronegative RA. The most common included nonerosive polymyalgia rheumatica in 16% of participants, psoriatic arthritis in 11%, osteoarthritis in 10%, spondyloarthritis in 8.7%, gout in 2.3%, and pseudogout in 3.9%.
“I think that’s sobering for you if you’re taking care of these patients, that maybe you need to rethink the diagnosis at every visit or at periodic intervals, especially if you’re going to change therapy,” advised Dr. Cush, who is professor of medicine and rheumatology at Baylor University Medical Center, Dallas, and director of clinical rheumatology at the Baylor Research Institute.
The Finnish rheumatologists observed that their findings have important implications both for clinical practice and for research, since RA clinical trials typically include a substantial proportion of seronegative patients.
“If seronegative patients are treated according to the treatment guidelines for progressive RA, a substantial proportion of patients is exposed to unnecessary long-term medication,” the investigators wrote, adding that their “results suggest that it may not be reasonable to study seronegative arthritis patients as a homogeneous entity in RA studies.”
The best recent data suggests about 15% of RA patients are seronegative, Dr. Cush said.
Delay in diagnosis is common in seronegative RA, as highlighted in a recent population-based study by Mayo Clinic rheumatologists. They reported that the median time from first joint swelling to diagnosis of seronegative RA using the 2010 American College of Rheumatology/European League Against Rheumatism criteria was 187 days, compared with a mere 11 days for seropositive RA. The median time to DMARD initiation was longer, too. Half of seropositive RA patients achieved remission within 5 years, as did 28% of seronegative patients, prompting the investigators to conclude “the window of opportunity for intervention may be more frequently missed in this group.”