BIRMINGHAM, Alabama—Data from the multiethnic US cohort of the LUMINA [LUpus in Minorities: NAture vs nurture] study of outcomes in systemic lupus erythematosus (SLE) show that African-American patients and those with more active lupus at diagnosis are more likely to develop myocarditis, which is associated with shorter survival. M. Apte et al from the LUMINA study group report the analysis early online in Rheumatology.¹

"Ethnicity and disease activity at diagnosis were associated with the occurrence of myocarditis in SLE. Myocarditis did not significantly impact on disease activity over time, but impacts on damage accrual and survival, reflecting overall the more severe disease those patients experience," Dr. Apte said.

The LUMINA researchers studied 496 SLE patients aged >16 with disease duration of <5 years. Patients in this study "have defined Hispanic, African-American, or Caucasian ethnicity (all four grandparents of the same ethnicity), [and] have met at least four revised and updated American College of Rheumatology criteria at diagnosis...." The researchers compared 53 patients who had myocarditis with those without myocarditis or its sequelae in the preceding year. They analyzed the association between myocarditis and baseline variables, the impact of myocarditis on SLE disease activity over time (SLAM-R), accrued SLE damage at last visit (SLICC Damage Index or SDI), and mortality.

They found that African-American SLE patients had a 12-fold elevated risk of myocarditis. "Although the association between African-American ethnicity and clinical myocarditis is not surprising, it has nevertheless not been described before. This association is unlikely to be due to confounding sociodemographic variables like poverty, education, and access to health care through availability of health insurance because patients with and without clinical myocarditis did not differ significantly in these variables," Dr. Apte commented.

The researchers suspect that the association between clinical myocarditis and disease activity at baseline indicates that most patients developed myocarditis early in the disease, before they entered LUMINA. "Myocarditis did not predict disease activity over time, but approached significance as a predictor of SDI [at baseline] in multivariate analyses, P = .051," they wrote.

Mortality was more than twice as high in the patients with clinical myocarditis (18.9% versus 8.4%). According to Dr. Apte, myocarditis exerts its effect in mortality indirectly, through higher damage accrual as measured by SDI. Mortality was particular high after 5 years of disease duration. "Our study thus suggests that the occurrence of myocarditis in lupus patients has intermediate and long-term consequences," the researchers concluded.

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