Impact of the 2019 European Alliance of Associations for Rheumatology/American College of Rheumatology Classification Criteria for Systemic Lupus Erythematosus in a Multicenter Cohort Study of 133 Women With Undifferentiated Connective Tissue Disease.

OBJECTIVE: We aimed to investigate the impact of applying the 2019 European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) classification criteria for systemic lupus erythematosus (SLE) in a previously described cohort of women with undifferentiated connective tissue disease (UCTD). METHODS: This study included 133 women with UCTD. At the time of inclusion into the study, none of the patients met any classification criteria for other defined systemic connective tissue disease. RESULTS: When applying the 2019 EULAR/ACR classification criteria to the cohort, 22 patients (17%) fulfilled the classification criteria for SLE. Patients classified as having SLE had significantly higher frequencies of mucocutaneous manifestations (23% versus 5%; P = 0.007), arthritis (59% versus 17%; P < 0.001), isolated urine abnormalities (18% versus 1%; P < 0.001), and highly specific antibodies (50% versus 15%; P < 0.001) compared to the other patients with UCTD. At follow-up, these patients were statistically significantly more likely to also meet the 1997 ACR revised SLE criteria and the Systemic Lupus International Collaborating Clinics (SLICC) criteria (18.2% versus 1.8%; P < 0.001) compared to the other UCTD patients. Patients who were diagnosed as having SLE according to the ACR 1997 update of the SLE revised criteria and the SLICC criteria during the follow-up scored higher on outcome measures when classified as having SLE according to the new 2019 EULAR/ACR classification criteria when compared to the other patients with UCTD (mean ± SD score 8.3 ± 3.7 versus 4.5 ± 4; P < 0.05). CONCLUSION: When applying the 2019 EULAR/ACR criteria for SLE in a cohort of patients with UCTD, we observed that in up to 17% of cases the original classification could be challenged. New implementation will help to identify earlier patients at higher risk of developing more severe CTD manifestations.

Applying SLICC and ACR/EULAR systemic lupus erythematosus classification criteria in a cohort of patients with undifferentiated connective tissue disease.

BACKGROUND/OBJECTIVE: New classification criteria for SLE have recently been developed. How these criteria affect the classification of patients with the SLE-mimicking condition UCTD is poorly understood. This study investigated the reclassification of UCTD patients using newly derived SLE criteria. METHODS: Patients with UCTD were identified within a single academic medical center using ICD9/10 codes. Medical record review was performed to confirm UCTD diagnosis and identify disease features present at diagnosis. The SLICC and ACR/EULAR criteria were applied, after which we compared the proportion of patients reclassified as SLE and determined which disease features were associated with reclassification. RESULTS: A total of 129 patients were included in the study. When applying the SLICC and ACR/EULAR criteria, 18 (14.0%) and 26 patients (20.2%) were reclassified as SLE. Comparison with McNemar's test trended toward statistical significance (p = 0.057). Cohen's kappa coefficient was 0.62 (p < 0.001), indicating substantial agreement between these criteria. Disease features associated with reclassification as SLE were renal involvement, leukopenia, thrombocytopenia, anti- dsDNA antibody, hypocomplementemia, non-scarring alopecia (SLICC), and arthritis (ACR/EULAR). CONCLUSIONS: Both the SLICC and ACR/EULAR criteria exhibit increased SLE classification. These newer classification criteria could be used to increase the number of SLE patients in future clinical studies.

Overlap of interstitial pneumonia with autoimmune features with undifferentiated connective tissue disease and contribution of UIP to mortality.

BACKGROUND AND OBJECTIVE: Criteria for interstitial pneumonia with autoimmune features (IPAF) were recently established for research purposes in a joint statement from the European Respiratory Society (ERS) and American Thoracic Society (ATS). We reviewed the utility of these criteria in patients previously diagnosed as broadly defined undifferentiated connective tissue disease (UCTD) and noted overlapping IPAF findings. Additional review was given to IPAF patients with usual interstitial pneumonia (UIP) on histopathology or radiology in terms of survival and outcome. METHODS: Patients with prior UCTD-interstitial lung disease (ILD) were screened by ERS/ATS criteria for IPAF. Clinical data along with all-cause mortality were collated and compared with selected idiopathic pulmonary fibrosis (IPF) patients from the same study period. Survival was compared between IPAF subgroups with and without UIP features. RESULTS: One hundred and one UCTD-ILD subjects (91%) evaluated from 2005 to 2012 also met strict criteria for IPAF. Frequent clinical findings included Raynaud's phenomenon, positive anti-nuclear antibody (ANA) and non-specific interstitial pneumonia (NSIP) pattern on chest computed tomography (CT). Nineteen had features of UIP either on histopathology or CT imaging. As compared with IPF, IPAF patients had overall better survival except in those with UIP features. CONCLUSION: Current IPAF criteria encompassed the majority of broadly defined UCTD-ILD and included those with UIP findings. Survival compared with IPF in those with UIP was similar. Further studies are necessary to refine IPAF definitions for clinical use and guide directed management strategies.