Evaluation of criteria contributions for the classification of systemic lupus erythematosus

The American Rheumatism Association (ACR) preliminary and revised criteria for classification of systemic lupus erythematosus (SLE) were evaluated for sensitivity and specificity in a population of 100 patients with SLE and 100 patients with other rheumatic diseases. Bayes' theorem was applied for evaluation of ARA criteria for the classification of SLE and a scoring system was developed which allows simple determination of the probability of SLE. The evaluation revealed considerable differences in values of the ARA criteria. The serologic tests and discoid lupus appeared to be the most distinctive criteria, while Raynaud's phenomenon, oral and nasal ulcers and arthritis were of little value. Comparison of SLE and control patients presenting the same number of criteria revealed that patients with SLE exhibit more distinctive criteria. This finding emphasizes the need for a quantitative evaluation of classification criteria.