Prevalence and Characteristics of Patients With Systemic Sclerosis Fulfilling the 2019 EULAR/American College of Rheumatology Classification Criteria for Systemic Lupus Erythematosus

Abstract

ObjectiveThere is limited literature describing the overlap of systemic sclerosis (SSc) and systemic lupus erythematosus (SLE), and the studies have employed a range of case definitions. Our study used the new EULAR/ACR SLE classification criteria to define SSc‐SLE cases among our center's SSc cohort.MethodsThis is a single‐center, retrospective study of a previously described cohort of SSc patients. Patient data were re‐abstracted to evaluate for fulfillment of the 2019 EULAR/ACR classification criteria for SLE. Demographic, laboratory, clinical features, and mortality were compared among SSc‐SLE patients and patients with SSc‐alone.ResultsAmong the 402 patients with SSc that were analyzed, 40 (10%) fulfilled the 2019 EULAR/ACR SLE criteria. Neuropsychiatric and renal involvement were rare. An initial SLE diagnosis was purported in 43% of the SSc‐SLE patients and 7% of SSc‐alone patients (p < 0.001). SSc‐SLE patients were more likely to be female, African American, and with limited cutaneous SSc. Anti‐U1RNP antibody positivity prevalence was 30% among SSc‐SLE patients and 6.6% among SSc‐alone patients (p < 0.001). Death during follow‐up occurred in 12 (30%) of SSc‐SLE patients and in 81 (22%) of SSc‐alone patients, but there was no difference in survival among the groups per log rank test (p = 0.404).Conclusion10% of SSc patients fulfill the 2019 EULAR/ACR Classification Criteria for SLE. These patients comprise a distinct demographic, serologic, and clinical phenotype but have similar severe SSc‐specific end‐organ damage and mortality as SSc‐alone patients. SLE patients with Raynaud's should be evaluated for SSc‐specific autoantibodies and scleroderma organ involvement.This article is protected by copyright. All rights reserved.