Clinical features and outcome of lupus myocarditis in the Western Cape, South Africa.

BACKGROUND: African American ethnicity is independently associated with lupus myocarditis compared with other ethnic groups. In the mixed racial population of the Western Cape, South Africa, no data exists on the clinical features/outcome of lupus myocarditis.

OBJECTIVES: The objective of this study was to give a comprehensive description of the clinical features and outcome of acute lupus myocarditis in a mixed racial population.

METHODS: Clinical records (between 2008 and 2014) of adult systemic lupus erythematosus (SLE) patients at a tertiary referral centre were retrospectively screened for a clinical and echocardiographic diagnosis of lupus myocarditis. Clinical features, laboratory results, management and outcome were described. Echocardiographic images stored in a digital archive were reanalysed including global and regional left ventricular function. A poor outcome was defined as lupus myocarditis related mortality or final left ventricular ejection fraction (LVEF) <40%.

RESULTS: Twenty-eight of 457 lupus patients (6.1%) met inclusion criteria: 92.9% were female and 89.3% were of mixed racial origin. Fifty-three per cent of patients presented within three months after being diagnosed with SLE. Seventy-five per cent had severely active disease (SLE disease activity index ≥ 12) and 67.9% of patients had concomitant lupus nephritis. Laboratory results included: lymphopenia (69%) and an increased aRNP (61.5%). Treatment included corticosteroids (96%) and cyclophosphamide (75%); 14% of patients required additional immunosuppression including rituximab. Diastolic dysfunction and regional wall motion abnormalities occurred in > 90% of patients. LVEF improved from 35% to 47% (p = 0.023) and wall motion score from 1.88 to 1.5 (p = 0.017) following treatment. Overall mortality was high (12/28): five patients (17.9%) died due to lupus myocarditis (bimodal pattern). Patients who died of lupus myocarditis had a longer duration of SLE (p = 0.045) and a lower absolute lymphocyte count (p = 0.041) at diagnosis. LVEF at diagnosis was lower in patients who died of lupus myocarditis (p = 0.099) and in those with a persistent LVEF < 40% (n = 5; p = 0.046).

CONCLUSIONS: This is the largest reported series on lupus myocarditis. The mixed racial population had a similar prevalence, but higher mortality compared with other ethnic groups (internationally published literature). Patients typically presented with high SLE disease activity and the majority had concomitant lupus nephritis. Lymphopenia and low LVEF at presentation were of prognostic significance, associated with lupus myocarditis related mortality or a persistent LVEF < 40%.