Table 1.
Study population characteristics and IIF and CTD screen results based on study group.
Fig 1.
CTD screen reactivity in patients with systemic rheumatic diseases compared with the control group.
The highest CTD screen reactivity was found in patients with systemic lupus erythematosus (SLE), whereas the lowest reactivity was found in the control group. Abbreviations: IIF, indirect immunofluorescence; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus; MCT, mixed connective tissue disease.
Table 2.
Qualitative and quantitative CTD screen results compared to IIF (n = 1093).
Fig 2.
Diagnostic performance of CTD screen and its combination with IIF for predicting systematic rheumatic diseases.
(A) Receiver operating characteristic (ROC) curves of CTD screen and its combination with indirect immunofluorescence (IIF) for discriminating total systemic rheumatic disease (n = 162) from the control group (n = 931). The areas under the ROC curves (AUCs) for CTD screen and its combination with IIF were 0.68 and 0.72, respectively, demonstrating a significant difference (P = 0.0054). (B) ROC curves for CTD screen and its combination with IIF for differentiating rheumatoid arthritis (RA) (n = 100) from the control group. The AUCs of CTD screen and its combination with IIF were 0.56 and 0.61, respectively. (C) ROC curves for the CTD screen combined with IIF for differentiating systemic lupus erythematosus (SLE) (n = 35) from the control group. The AUCs of CTD screen and its combination with IIF were 0.92 and 0.94, respectively. (D) ROC curves for CTD screen and its combination with IIF for discriminating mixed connective tissue disease (MCT) (n = 23) from the control group. The AUCs of CTD screen and its combination with IIF were 0.80 and 0.85, respectively, and they were statistically different (P = 0.0410).
Table 3.
Sensitivity, specificity, and ROC-AUC of CTD screen, tested independently and in combinationa.
Table 4.
Multivariate analysisa of the outcomes of systematic rheumatic disease.