Application of the 2012 Systemic Lupus International Collaborating Clinics classification criteria to patients in a regional Swedish systemic lupus erythematosus register

Abstract

IntroductionIn 2012, the Systemic Lupus International Collaborating Clinics (SLICC) network presented a new set of criteria (SLICC-12) to classify systemic lupus erythematosus (SLE). The present study is the first to evaluate the performance of SLICC-12 in an adult European study population. Thus, SLICC-12 criteria were applied to confirmed SLE cases in our regional SLE register as well as to individuals with a fair suspicion of systemic autoimmune disease who were referred to rheumatology specialists at our unit.MethodsWe included 243 confirmed SLE patients who met the 1982 American College of Rheumatology (ACR-82) classification criteria and/or the Fries ‘diagnostic principle’ (presence of antinuclear antibodies on at least one occasion plus involvement of at least two defined organ systems) and 55 controls with possible systemic autoimmune disease, including the presence of any SLE-related autoantibody.ResultsSLICC-12 showed a diagnostic sensitivity of 94% (95% confidence interval (CI), 0.90 to 0.96) compared with 90% (95% CI, 0.85 to 0.93) for the updated set of ACR criteria from 1997 (ACR-97), whereas ACR-82 failed to identify every fifth true SLE case. However, the disease specificity of SLICC-12 reached only 74% (95% CI, 0.60 to 0.84) and did not change much when involvement of at least two different organs was required as an indicator of systemic disease. In addition, SLICC-12 misclassified more of the controls compared to ACR-82, ACR-97 and Fries.ConclusionsEstablishing a standard definition of SLE continues to challenge lupus researchers and clinicians. We confirm that SLICC-12 has advantages with regard to diagnostic sensitivity, whereas we found the diagnostic specificity to be surprisingly low. To accomplish increased sensitivity and specificity figures, a combination of criteria sets for clinical SLE studies should be considered.

Epidemiology of lupus

“…Therefore, the SLICC group created new classification criteria derived from 702 expert-rated patient scenarios that resulted in fewer misclassifications, greater sensitivity, and equal specificity compared with the ACR criteria [8]. Studies [15][16][17][18][19] have begun to explore its performance externally.…”

Toward new criteria for systemic lupus erythematosus—a standpoint

“…Several groups have compared the two sets, and there is complete agreement that the SLICC criteria are more sensitive. 13,[17][18][19][20] The SLICC criteria sensitivity has been found in the range between 92% and 97%, whereas the 1997 ACR criteria had 77% to 91% sensitivity. However, and not entirely unexpectedly given the similar structure, specificity dropped from 91-96% for the 1997 ACR criteria to 74-88% for the SLICC criteria.…”

Specificity of Systemic Sclerosis Classification Criteria

“…This is certainly in the same range or better than figures for the specificity of other rheumatic disease criteria 9,10,11,12,13,14 .…”