Researchers Should Use ACR/EULAR Definition of RA Remission in Clinical Studies

In clinical trials, rheumatologists should use the ACR/EULAR definition for rheumatoid arthritis (RA) remission instead of the Disease Activity Score-28-CRP (DAS28-CRP), according to David Felson, MD, MPH, professor of medicine, Boston University School of Medicine.

Dr. Felson

This is because patients may still have swollen joints and not actually be in remission under the DAS28 criteria. Dr. Felson addressed the challenges of defining RA remission during the inaugural ACR-FDA Summit, held online in May.

Dr. Felson was part of an ACR/EULAR committee that developed a provisional definition of remission in 2011.¹ The ACR/EULAR criteria included two ways of defining remission. One was a Boolean-based definition that required patients to have a tender and swollen joint count equal to or less than 1, a C-reactive protein (CRP) level equal to or less than 1 mg/dL and a patient global assessment of arthritis activity equal to or less than 1 (on a 0 to 10 scale). The second was a Simplified Disease Activity Index score equal to or less than 3.3.

Patient-reported outcomes (PROs) have been shown to be the most sensitive for demonstrating outcomes, Dr. Felson said. The committee’s research at the time also found that the DAS28-CRP was not an acceptable definition of remission because it did not provide enough relief for patients.

An Evolving Definition

The definition for RA remission continues to evolve as treatments change, Dr. Felson said. Today, some researchers continue to use the DAS28-CRP to define remission, and others still question whether it is appropriate to include a PRO when assessing remission.

“I’m troubled that we can define RA without asking how patients are doing,” Dr. Felson said. “This is the RA outcome most sensitive to change.”

Use of the DAS28 may continue today because of its lenient definition of remission. This makes it easier to achieve a difference between two types of therapy, Dr. Felson explained.

This year, ACR/EULAR approved a definition of remission that is no longer provisional.² Under the new definition, the patient global assessment of arthritis activity must be 2 or less on a 0 to 10 scale.

Dr. Felson advised attendees to use the ACR/EULAR definition of remission in trials. A version excluding CRP is available for practice. He added that journals affiliated with the ACR or EULAR will not publish trials that only use the DAS28 to define RA remission.