ACR and EULAR New Diagnostic Criteria for RA
ACR and EULAR New Diagnostic Criteria for RA
The ACR and the European League Against Rheumatism (EULAR) installed a joint working group that developed, in three phases, a new approach to classifying RA in this era of early arthritis clinics. The group focused on patients newly presenting with undifferentiated inflammatory synovitis. Nine early arthritis cohorts were used. Assuming that persistent polyarthritis and erosive disease are specific for RA, the working group identified factors that best discriminated between those who were and those who were not at high risk for these finding, being the appropriate current paradigm underlying the disease construct of RA. In a first phase, variables were identified that were the most predictive of the decision to initiate methotrexate in a population of patients with early undifferentiated arthritis. The initiation of methotrexate was used as an indicator that the patient was considered to be suffering from RA. The expert working group analyzed standardized clinical and laboratory variables available at baseline up to the initiation of methotrexate within the next 12 months. The analyses identified the independent contribution of each variable.
In the second phase, a clinician-based judgment on the relative contribution of each variable in influencing the probability of developing RA was addressed using real-life patient case scenarios. Finally, a scoring system was developed for the identification of patients with the highest probability of developing RA, to be used in newly presenting patients.
To be classified as 'definite RA' requires the confirmed presence of synovitis in at least one joint, the absence of an alternative diagnosis for the observed arthritis, and a total score of at least 6 from the individual scores in four domains: number and site of involved joints (range 0–5), serological abnormalities (range 0–3), elevated acute-phase response (range 0–1), and symptom duration (two levels; range 0–1). The classification criteria are summarized in Table 1.
Finally, the proposed criteria were validated in three different cohorts that had not been used in the identification of variables in phase 1. Among cohort participants who were treated with methotrexate within a year from symptom onset, the proportions that could be classified as definite RA according to the proposed criteria (score of 6 or greater) were 97, 91 and 87% in each cohort, respectively.
Some remarks have to be made with respect to the methodology followed for the development of the new criteria. Firstly, the new criteria are classification criteria, so the primary goal is to use them for classification of patients in clinical and epidemiological studies. However, these criteria can only be scored during the early phase of the disease, which is not necessarily the moment of inclusion in a clinical study. It is therefore likely that the new criteria will be used to guide clinical practice. Huizinga and van der Helm-van Mil stressed that the 2010 criteria can only be used as diagnostic criteria after it has been demonstrated that patients who fulfill them have a high chance for a persistent or destructive disease course. Moreover, they stated that although the 2010 criteria were developed with the idea that patients should receive methotrexate, the available evidence that patients who fulfill the 2010 criteria benefit from starting disease modifying drugs is limited.
Another important point that should be mentioned is that in the cohorts used, the surrogate endpoint for definite RA was prescription of methotrexate. The prescription of methotrexate over many years of inclusion in these cohorts depended on the at that time prevalent beliefs of attending rheumatologists and not necessarily reflect current guidelines.
A strong point of the new criteria is the fact that on the one hand the criteria are based on real patient data while on the other hand used clinical expertise.
Ultimately, the value of new criteria lies in the appreciation of the field, in this case the scientific as well as the clinical communities in rheumatology. Fortunately, at the moment of writing this review, many publications have already evaluated the performance of the New ACR/EULAR classification criteria for rheumatoid arthritis.
New Classification Criteria for Rheumatoid Arthritis
The ACR and the European League Against Rheumatism (EULAR) installed a joint working group that developed, in three phases, a new approach to classifying RA in this era of early arthritis clinics. The group focused on patients newly presenting with undifferentiated inflammatory synovitis. Nine early arthritis cohorts were used. Assuming that persistent polyarthritis and erosive disease are specific for RA, the working group identified factors that best discriminated between those who were and those who were not at high risk for these finding, being the appropriate current paradigm underlying the disease construct of RA. In a first phase, variables were identified that were the most predictive of the decision to initiate methotrexate in a population of patients with early undifferentiated arthritis. The initiation of methotrexate was used as an indicator that the patient was considered to be suffering from RA. The expert working group analyzed standardized clinical and laboratory variables available at baseline up to the initiation of methotrexate within the next 12 months. The analyses identified the independent contribution of each variable.
In the second phase, a clinician-based judgment on the relative contribution of each variable in influencing the probability of developing RA was addressed using real-life patient case scenarios. Finally, a scoring system was developed for the identification of patients with the highest probability of developing RA, to be used in newly presenting patients.
To be classified as 'definite RA' requires the confirmed presence of synovitis in at least one joint, the absence of an alternative diagnosis for the observed arthritis, and a total score of at least 6 from the individual scores in four domains: number and site of involved joints (range 0–5), serological abnormalities (range 0–3), elevated acute-phase response (range 0–1), and symptom duration (two levels; range 0–1). The classification criteria are summarized in Table 1.
Finally, the proposed criteria were validated in three different cohorts that had not been used in the identification of variables in phase 1. Among cohort participants who were treated with methotrexate within a year from symptom onset, the proportions that could be classified as definite RA according to the proposed criteria (score of 6 or greater) were 97, 91 and 87% in each cohort, respectively.
Some remarks have to be made with respect to the methodology followed for the development of the new criteria. Firstly, the new criteria are classification criteria, so the primary goal is to use them for classification of patients in clinical and epidemiological studies. However, these criteria can only be scored during the early phase of the disease, which is not necessarily the moment of inclusion in a clinical study. It is therefore likely that the new criteria will be used to guide clinical practice. Huizinga and van der Helm-van Mil stressed that the 2010 criteria can only be used as diagnostic criteria after it has been demonstrated that patients who fulfill them have a high chance for a persistent or destructive disease course. Moreover, they stated that although the 2010 criteria were developed with the idea that patients should receive methotrexate, the available evidence that patients who fulfill the 2010 criteria benefit from starting disease modifying drugs is limited.
Another important point that should be mentioned is that in the cohorts used, the surrogate endpoint for definite RA was prescription of methotrexate. The prescription of methotrexate over many years of inclusion in these cohorts depended on the at that time prevalent beliefs of attending rheumatologists and not necessarily reflect current guidelines.
A strong point of the new criteria is the fact that on the one hand the criteria are based on real patient data while on the other hand used clinical expertise.
Ultimately, the value of new criteria lies in the appreciation of the field, in this case the scientific as well as the clinical communities in rheumatology. Fortunately, at the moment of writing this review, many publications have already evaluated the performance of the New ACR/EULAR classification criteria for rheumatoid arthritis.
Source...