Effects of SLE Diagnosis Examined in Antiphospholipid Antibody-Positive Patients

The diagnosis of systemic lupus erythematosus (SLE) in patients who are persistently antiphospholipid (aPL) antibody positive is associated with an increased occurrence of thromobocytopenia, hemolytic anemia, low complement levels, and immunoglobulin A (IgA) anti-β₂ glycoprotein-I antibody (aβ₂GPI) positivity, according to the results of an analysis of the large-scale, multicenter, international Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION) registry published in Arthritis Care & Research.

The investigators sought to compare the clinical, laboratory, and treatment characteristics of aPL-positive patients with and without SLE. In addition, they analyzed the frequency of traditional cardiovascular disease (CVD) risk factors in aPL-positive patients with and without SLE and the pattern of hydroxychloroquine (HCQ) use among those who were aPL positive and had no other autoimmune diseases.

They hypothesized that patients who are aPL positive and have SLE have increased rates of aPL-related clinical manifestations, traditional CVD risk factors, lupus-related antibodies, and immunosuppressive use, compared with patients without SLE.

A total of 623 people who were aPL positive were evaluated, 426 of whom were without other autoimmune diseases and 197 of whom had SLE. Overall, 59 patients in the aPL-only group exhibited SLE-like disease. Mean participant age at study entry was 44.2±12.8 years; 74% of the participants were white.

Higher rates of thrombocytopenia, hemolytic anemia, low complements, and IgA aβ₂GPI were reported among participants who were aPL positive and had SLE, whereas higher rates of cognitive dysfunction and IgG aβ₂GPI were reported among those in the aPL-only group. Rates of arterial and venous thromboses and pregnancy-related morbidity were similar between the groups. The prevalence of CVD risk factors at the time of the registry did not differ between the 2 groups except for smoking status, which was reported significantly more often in those who were aPL positive and had SLE compared with participants in the aPL-only group (15% vs 9%; P =.03).

Even though HCQ use was more common among participants who were aPL positive and had SLE, 40% of those in the aPL-only group also received HCQ, particularly individuals with lupus-related clinical and serologic manifestations.

The investigators concluded that this exploratory study provides preliminary data for future risk-stratified prospective analyses of the APS ACTION registry, which will help to better establish the clinical effect of SLE on the presentation and disease characteristics among those who are aPL positive. 

Disclosures: Dr Belmont is a consultant to Exagen Diagnostics, Inc. Dr Erkan received research grants from New York Community Trust, Hospital for Special Surgery Medical Education Academy, Lupus Clinical Trials Consortium, and the National Heart, Lung, and Blood Institute. Dr Erkan is a clinical trial investigator for EMD Serono, GSK, and Xencor and is a consultant for Ablynx.

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Reference

Unlu O, Erkan D, Barbhaiya M, et al; on behalf of APS ACTION. The impact of systemic lupus erythematosus on the clinical phenotype of antiphospholipid antibody positive patients: results from AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION) Clinical Database and Repository [published online April 18, 2018]. Arthritis Care Res (Hoboken). doi: 10.1002/acr.23584