Prevalence of antiphospholipid antibodies in patients with overt myocardial dysfunction in systemic lupus erythematosus. A case-control study

BACKGROUND: Small case-series have reported overt myocardial dysfunction to be associated with positive antiphospholipid antibodies in patients of systemic lupus erythematosus (SLE). However, there is no case-control study that has examined this association. METHODS: This case-control study recruited patients of SLE (fulfilling SLICC criteria) with overt myocardial dysfunction as cases and those without this as controls. Overt myocardial dysfunction was defined by echocardiography as global left ventricular dysfunction and reduced ejection fraction (<50%). Those patients with a prior diagnosis of anti-phospholipid antibody syndrome, coronary artery disease, rheumatic heart disease or severe pulmonary artery hypertension were excluded. Antibodies tested included lupus anticoagulant, anticardiolipin antibodies (IgM and IgG) and anti-beta 2 glycoprotein 1 antibodies (IgM and IgG). Patients with positive tests underwent repeat testing for persistent positivity after 12 weeks. RESULTS: This study included 51 patients (21 cases and 30 controls) having a mean (SD) age of 33 (13.3) years, and disease duration (median, IQR) of 28 months (12-38 months). The mean ejection fraction of cases was 31.7 (9.3)% while that of controls was 55.7 (1.7)% (p = 0.03). The frequency (percentage) of positive antiphospholipid antibodies was not significantly different between cases and controls (43%, 40%, p = 0.8). The frequency (percentage) of anti-cardiolipin antibody was also not significant between the groups (38%, 37%, p = 0.57). Serositis and leucopenia were more prevalent in SLE patients with myocardial dysfunction (p = 0.005). CONCLUSION: This study did not find any significant association of anti-phospholipid antibodies with overt myocardial dysfunction in patients of SLE.