The EULAR/American College of Rheumatology 2019 classification criteria for systemic lupus erythematosus did not perform significantly better than the ACR 1997 and SLICC 2012 criteria, according to findings published in Arthritis Care & Research.
“Classification criteria aren’t the same as diagnostic criteria but are often helpful — and used —in clinical practice,” Michelle Petri, MD, MPH, of the Johns Hopkins University School of Medicine, told Healio Rheumatology. “There are now three different sets of classification criteria for lupus, so rheumatologists need to know which one fits their practice best.”
The EULAR/American College of Rheumatology 2019 classification criteria for systemic lupus erythematosus did not perform significantly better than the ACR 1997 and SLICC 2012 criteria in an independent, multinational cohort, according to findings. Source: Adobe Stock
According to the researchers, the 1997 ACR revised criteria and the SLICC 2012 criteria counted each SLE manifestation equally with one exception — the SLICC criteria counted lupus nephritis by biopsy as a “stand alone,” and sufficient for classification.
“However, when physicians evaluate a patient for SLE, they may give greater weight to some non-renal criteria over other non-renal criteria,” they wrote. “… Therefore, we hypothesized that a classification score that gave greater weight to some non-renal criteria than others might have greater agreement with physician diagnosis.”
Michelle Petri
Petri and colleagues’ aims were threefold: To develop and test a classification rule that differentially weighted the variables in the SLICC classification, then compare that rule with the EULAR/ACR 2019 rule that used a weighted approach, and compare the revised ACR 1997 and original SLICC rule to the new EULAR/ACR 2019 rule. The researchers reused the physician-rated patient scenarios that helped derive the SLICC 2012 criteria to create their own weighted classification rule. These scenarios were based on 293 patients with SLE and 423 others with non-SLE rheumatic conditions.
The researchers then used a multiple linear regression model to analyze these data, with the SLICC 2012 criteria variables as predictors and the binary outcome — physician-classified SLE as the “gold standard” — as the outcome. They evaluated the performance of the rule based on an independent set of expertdiagnosed patient scenarios, and compared it with the previously reported classification rules. These patient scenarios were collected and rated in a similar manner to those used in the derivation step, and included 337 patients with SLE and 353 individuals with non-SLE rheumatic diseases.
According to the researchers, the weighted SLICC criteria and the EULAR/ACR 2019 criteria demonstrated less sensitivity but better specificity than the listbased, revised ACR 1997 and SLICC 2012 criteria. Further, there were no statistically significant differences between any pair of rules regarding overall agreement with the physician diagnosis.
“By using physicians’ diagnosis as the gold standard, it was determined that sensitivity and specificity were optimized when patients were classified as SLE if they had lupus nephritis and/or if on the new weighted criteria they achieved 56 points or more with at least one clinical component and one immunologic component,” Petri and colleagues wrote.
In an interview, Petri further condensed the findings to a few words.
“Bottom line: They all work and correlate highly,” she said. “None is truly ‘better.’”
