Overreliance on DAS scores undermines rheumatoid arthritis management



– Two major changes that improved RA management in recent years – the introduction of potent biologic and targeted synthetic drugs to control inflammatory disease, and the treat-to-target strategy – have also produced an unanticipated snag in the care patients receive. Their persistent comorbidities and their more atypical rheumatoid manifestations often go overlooked and untreated.

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The situation has been dubbed “DAS blindness,” when clinicians caring for patients with RA are so focused on a patient’s disease activity score (DAS), measured by counting their swollen and tender joints (usually 28 joints to tally the DAS28 score), that they lose sight of other important features of a RA patient’s disease such as pain and fatigue, Ruth Williams, MBChB, said in an invited talk at the European Congress of Rheumatology.

“There is so much focus on the DAS28 that people are blinded by it. Clinicians concentrate too much on the primary physical condition” of RA, “and they miss important functional, psychological, and social impacts of the disease,” said Dr. Williams, a general-practice physician who is also a long-time RA patient who works as a patient representative and RA researcher at King’s College London.

In Dr. William’s extended personal experience as an RA patient (she was first diagnosed in 1966 as a child), management of the disease changed dramatically with the relatively recent, widespread adoption of the DAS28 score in routine clinical practice in Europe and the United States, migrating from its initial use in research studies. Once her clinicians began to use the DAS28 “I felt that perhaps I wasn’t being seen anymore. It was just the biology of my disease being noted rather than me as an individual,” Dr. Williams said in an interview. Clinicians “need to discuss with patients what remission means to them, and their objectives” from treatment, because a patient’s treatment goals may go beyond just reducing the number of swollen or tender joints they total in the DAS28 assessment.

Rheumatologists also have begun to recognize this common disconnect between both the assessment and the antirheumatoid treatment that RA patients routinely receive, and the symptoms that cause problems for RA patients that are not directly tied to their inflammatory disease. Patients can present with remission-level responses in their tender and swollen joint counts and in their serum level of C-reactive protein or erythrocyte sedimentation rate but still score high on the patient global assessment (PGA) scale, a residual consequence of RA that places them out of remission range based on the 2011 “Boolean” criteria for RA remission in trials endorsed by the American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) (Arthritis Rheum. 2011 Mar;63[3]:373-86).

In a review of 411 RA patients who met three of the four ACR/EULAR criteria that collectively define remission, 61% missed on the PGA measure (Ann Rheum Dis. 2012 Oct;71[10]:1702-5), noted Joan M. Bathon, MD, professor of medicine and director of rheumatology at Columbia University, New York, in a talk during the Congress. Another review of 273 RA patients who missed on one of the four criteria showed 80% missing because of their PGA score (Arthritis Res Ther. 2013;15:R221). The specific clinical features that triggered high PGAs in these patients were things like fibromyalgia, back pain, anxiety, depression, and rheumatoid activity in joints not included in the DAS28 score, Dr. Bathon noted. The PGA can have poor correlation with the other three measures, but that is a strength because it reflects different dimensions of RA that are important to patients. When the PGA is discordant with the other three measures of remission, it may not make sense to try to improve it by simply using more immunosuppressive treatment.

The solution to the dilemma of what remission target to aim for when treating to target is to apply common sense to existing guidelines and recommendations and tailor management to each patient, she concluded. “The worst thing we can do is to take criteria meant for clinical rials and for patients with average scores and apply them to every individual patient,” she said. Remission guidelines are good for large populations, “but we shouldn’t apply them to every single patient without thinking.”

A similar plea for thoughtful use of the treat-to-target model and immunomodulatory treatment came in a separate talk from Laure Gossec, MD, a professor of rheumatology at Pitie-Salpétriere Hospital and Sorbonne University in Paris.

The challenge of DAS28 is that it was a remission criteria developed by the ACR and EULAR to use in clinical trials that was coopted for use in routine practice. Despite that, Dr. Gossec believes that DAS28 largely succeeded in this transition. “The DAS28 performs well, it has good prognostic capacity and is widely used.” In her practice, Dr. Gossec relies on the DAS28 score as her primary tool to track disease status in RA patients. “It’s not perfect, but I’m familiar with it, and I work with it,” she said.

It’s undeniable, she acknowledged, that a high PGA often stands between a patient and remission. PGA “is hard to use to guide anti-inflammatory treatment. Many patients have high PGA scores even though they have no inflammation.” Discrepancies like this create a case for dual-treatment targets, both a low swollen and tender joint count and low PGA, as separate and equal treatment goals, Dr. Gossec said, an approach she and her associates proposed in a recent article (Arthritis Care Res. 2018 Mar;709[3]:369-78).

Dr. Williams had no disclosures. Dr. Bathon has been a consultant to AbbVie and has received research funding from Bristol-Myers Squibb and Pfizer. Dr. Gossec has been a consultant to and has received research funding from several companies.

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