Patients with rheumatoid arthritis (RA) periodically experience surges in inflammatory activity known as flares. During a flare, the level of fatigue and joint symptoms such as pain, swelling, and stiffness temporarily increase.1 Flares are unpredictable and often debilitating. The lack of a standard definition for disease flare and the inconsistent terminology used by physicians and patients to describe flares further complicates efforts to recognize and manage them.

Over the past several years, Caroline Flurey, PhD, senior lecturer in public health, University of the West of England, Bristol, United Kingdom, and other researchers affiliated with the Outcome Measures in Rheumatology (OMERACT) initiative, have worked to establish a consensus definition of an RA flare that incorporates the patient perspective and to create a reliable tool for measuring flare severity.1-3

“The OMERACT RA Flare Group found that patients with RA use different criteria — or domains — to identify a flare and that patients and providers differ in the domains they consider central to a flare,” Dr Flurey explained in an interview with Rheumatology Advisor. “Because of how important it is for healthcare providers to understand what each individual patient means by [a] flare, the OMERACT Flare Group developed the RA Flare Core Domain Set,” she said.

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Defining Flare

An international group of researchers, clinicians, and patients established the OMERACT RA Flare Group in 2006. Since then, the group has worked diligently to define what constitutes a flare, understand how a flare affects patients and treatment decisions, and develop a reliable instrument for measuring RA flares.3

The definition of flare the OMERACT group agreed upon is an “episode of increased RA disease activity accompanied by worsening symptoms, functional impacts, and clinical indicators of sufficient magnitude and duration to place individuals at greater risk of joint damage and poorer outcomes when left untreated.”3

The group also identified 9 domains that more than 70% of patients and healthcare providers who participated in the workshops agreed were core contributors to an RA flare: pain, physical function, tender joints, swollen joints, patient global score from the American College of Rheumatology (ARC) RA core set, fatigue, stiffness, participation, and self-management.4

A key strength of the OMERACT RA Flare Core Domain Set is that it goes beyond physical symptoms to include measures such as the patient’s ability to participate in activities and to self-manage a flare. As Dr Flurey explained, RA is a constant backdrop to patients’ lives and they practice many strategies to manage its symptoms. At the start of a flare, however, RA shifts into the foreground.1

“My research has found patients will try everything they can think of to manage their symptoms before they seek medical help. The tipping point for recognizing a flare is when they can no longer control their symptoms on their own,” she said.

The Disease Activity Score (DAS) 28 is frequently used in trials and in practice to identify flares, but a distinct disadvantage of the DAS28 is that it does not measure fatigue. “Although physicians did not rate fatigue very highly as a critical domain, fatigue emerged as a key symptom in patients’ definition[s] of flare, and many patients considered fatigue more important than flare,” Flurey said..

Identifying Flares

The OMERACT RA Flare Group developed a flare assessment questionnaire based on patient-reported outcomes (PROs) from the core domain set.3 The questionnaire was administered to 850 participants in the Canadian Early Arthritis Cohort observational study between November 2011 and November 2014.

The flare assessment started by having patients rate change in their RA since the prior visit on a 7-point scale that ranges from “much worse” to “much better.” Next, patients were asked whether they were currently experiencing a flare. Patients who answered yes were told to rate the severity from 0 to 10 and indicate the duration of the flare. All patients were told to complete the remaining questions, which had them rate pain, function, fatigue, stiffness, difficulty with participation, and ability to self-manage on a scale of 0 to 10, with 0 representing no problem.

Patients were also instructed to identify tender and swollen joints on a 40-joint homunculus. The questionnaire was administered at each visit, along with other PRO instruments and the ACR core set to capture physician and patient assessments; a DAS28 was also calculated.3

Investigators compared agreement between patient reports, physician ratings, and DAS28 criteria in patients who completed at least 2 flare assessments. They also assessed concordance between the OMERACT questionnaire and other PROs.

At the second visit, 24% patients said they were having a flare. Physicians identified 32% of patients as flaring, and the DAS28 showed 16% were flaring. Patients and physicians were more likely to agree the patient was having a flare if RA was well-controlled at the prior visit.

The greatest discordance was between physicians and DAS28 when patients had moderate to high disease activity.3 The fact that the DAS28 does not capture many core domains providers and patients consider critical for measuring a flare (beyond the global assessment) may explain the poor concordance between patient reports, physician ratings, and the DAS28.

Results of the OMERACT flare assessment correlated with the results of other PROs that used similar domains. Mean scores for each question were significantly higher in patients who said they were having a flare than patients who said they were not having a flare (P <.0001).

When patients and physicians identified the patient as having a flare, the flare assessment was significantly more likely to show worsening RA since the prior visit (P <.0001), greater flare severity (P <.001), and greater change in DAS28 (P <.0001).3

Scores showed little change in patients who were not having a flare at the time of the initial or subsequent visit. 


Preliminary findings suggest that the OMERACT flare assessment is an effective tool for identifying RA flares. The data also show that providers and patients typically agree on flare status, especially if the patient’s RA was controlled before the flare.3

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  1. Flurey CA, Morris M, Richards P, Hughes R, Hewlett S. It’s like a juggling act: rheumatoid arthritis patient perspectives on daily life and flare while on current treatment regimes. Rheumatology (Oxford). 2013;53(4):696-703.
  2. van Tuyl LH, Sadlonova M, Davis B, et al. Remission in rheumatoid arthritis: working toward incorporation of the patient perspective at OMERACT 12. J Rheumatol. 2016;43(1):203-207.
  3. Bykerk VP, Bingham CO, Choy EH, et al. Identifying flares in rheumatoid arthritis: reliability and construct validation of the OMERACT RA Flare Core Domain Set. RMD Open. 2016;2:e000225.
  4. Bykerk VP, Lie E, Bartlett SJ, et al. Establishing a core domain set to measure rheumatoid arthritis flares: report of the OMERACT 11 RA Flare Workshop [published online [published online March 1, 2014]. J Rheumatol. 2014;41(4):799-809.

This article originally appeared on Rheumatology Advisor