PoM No 4,2013

Publication of the Month

 

April 04/13: How are the new ACR/EULAR classification criteria performing?

 PART 1:  

Key messages:    

  • The ACR/EULAR RA classification criteria have now been tested in several clinical cohorts and settings
  • The utility of the ACR/EULAR RA classification criteria for non-arthritis health care practitioners remains questionable

Bykerk V, Massarotti E.
The new ACR/EULAR classification critria for RA: how are the new criteria performing in the clinic?
Rheumatology 2012;51:vi10-vi15   

Background:  In 2010, the ACR and European League Against Rheumatism (EULAR) published updated classification criteria for Rheumatoid Arthritis (RA) in order to distinguish patients at high risk for developing erosive and/or inflammatory disease from those with undifferentiated inflammatory arthritis. The emphasis was on the application of these criteria to patients with early rather than established disease.  Like the 1987 ACR system, the new criteria are principally intended to classify patients for the purpose of allowing a common approach for comparison across studies. This review article summarizes the available data on the performance of the new criteria – bearing in mind that these criteria, like the former, may well be used as diagnostic tools in clinical practice.  

Summary: Several studies were evaluated.  One found that there was no significant difference between the diagnostic accuracy of the 2010 criteria versus the 1987 criteria but all other studies found a higher sensitivity in the newer criteria – measured against the gold standard of combined specialist diagnosis and clinical necessity for methotrexate.  Two papers included a caution on the possibility of decreased specificity with the newer system and a warning that overtreatment is to be avoided. A suggested diagnostic algorithm is included, with a clear emphasis on careful consideration of other possible diagnoses.  

Conclusions: Therapeutic advances including the use of biologic agents for the treatment of RA over the last decade along with the new classification criteria for RA which incorporates the more specific ACPA antibodies test has allowed for earlier identification of the disease and the possibility of improvements in disease outcome.  

Comment: Whilst the diagnosis of RA remains clinical, the ACR/EULAR 2010 criteria are still probably best used by specialist arthritis health care practitioners. However, the diagnosis of RA patients can now be made earlier using the new criteria.  

 

PART 2:

 

Key messages: 

  • The 2010 RA classification criteria identify more patients with RA who would previously have been designated as having undifferentiated arthritis.
  • These patients have lower disease activity score at the time of identification.

 Bykerk V, Jamal S, Boire G, Hitchon C, Haraoui B, Pope J, Thorne J, Sun Y and  Keystone E.
The Canadian Early Arthritis Cohort (CATCH): Patients with New-onset Synovitis Meeting the 2010 ACR/EULAR Classification Criteria But Not the 1987 ACR Classification Criteria Present with Less Severe Disease Activity
J Rheumatol 2012;39;2071-2080    

Background: Since 2007, patients with early inflammatory arthritis have been recruited to the CATCH programme.  Collecting and analysing nationally generated data on early rheumatoid arthritis (ERA) has enabled the validation of clinical diagnostic and assessment tools, standardization of protocols and convenient and easy access to data for future investigations. After a cut-off date of March 15, 2011, available data was collated and analysed.   

Summary: 1187 of the originally enrolled 1450 patients were followed and included in the data analyses described giving a useful statistical base. Many interesting demographic and disease characteristics are analysed, the details of which are beyond this summary.  However, of direct relevance to this month’s topic are the findings that:  

  •  When stratified by year of study entry, there was a trend for median symptom duration to decrease over time between 2007-2011 and
  • 855 patients of 908 with baseline radiographs available would classify as RA under both the 1987 system and the 2010 one.  Of the 612 patients without erosions at baseline, 63% met 1987 criteria while 83% met the 2010 criteria.
  • Fewer patients (32%) identified only by the 2010 criteria had a DAS28>5.1 than patients identified by the 1987 criteria (52%). 

Conclusions: The 2010 RA classification criteria identify more patients with RA who would previously have been designated as having undifferentiated arthritis.  However, these patients have lower disease activity at the time of diagnosis.  

Comment: This on-going study gives the characteristics of the ERA population in Canada. While it is too early to fully address the influence of the 2010 criteria, interesting trends including earlier diagnosis and lower baseline erosive damage may be starting to appear.  The high remission rate could reflect the earlier recruitment and the evolution of trends in treatment.  Further analysis of these aspects will be eagerly awaited.   

 

As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.