Clinical characteristics and outcomes of lupus myocarditis: a retrospective case control study in Chinese patients.

OBJECTIVES: The aim of this study was to investigate the clinical features and outcomes of systemic lupus erythematosus (SLE) with myocarditis. METHODS: A retrospective study was conducted in all inpatients diagnosed with SLE and concurrent lupus myocarditis (LM) at Peking Union Medical College Hospital (PUMCH) from July 2013 to July 2019. The case group included patients with LM while patients in the control group were enrolled randomly at a ratio of 1:1 and age- and year-matched SLE patients without myocarditis during the same period. Clinical characteristics and outcomes of LM patients were collected. RESULTS: Among 4719 SLE patients hospitalized to PUMCH over the 6-year period, 79 (1.67%) were diagnosed with LM, with a mean age of 32.38 ± 13.55 years and 89% were female. 52 (66%) cases presented abnormal ventricular wall motion function, and 30 (38%) cases showed a decreased left ventricular ejection fraction (LVEF) (<50%) in echocardiography. 10 (13%) LM patients died during hospitalisation. For risk factors of myocarditis, patients in the LM group had higher percentage of on neurological involvement, higher SLE disease activity index 2000 (SLEDAI-2K) scores, and higher rates of positive anti-nucleosome antibodies compared with the control group. Multivariate logistic regression demonstrated that low levels of C3 and high SLEDAI-2K scores were the independent risk factors for developing LM in SLE patients (OR=0.870, 95%CI 0.762-0.994, p=0.041; OR=1.058, 95%CI 1.008-1.110, p=0.023, respectively). CONCLUSIONS: Cardiac involvement especially myocarditis in SLE remains a rare but serious manifestation. Our research provided further insights into clinical features and risk factors of LM. Clinicians should be alerted for LM after cardiac manifestations occurred among those with SLE, which may reduce the risk of death.