Objectives: There are no population-based estimates of the incidence or risk factors for acute cardiac manifestations in children with systemic lupus erythematosus (SLE) to guide screening and diagnostic imaging practices. We estimated the incidence and prevalence of acute cardiac manifestations of child-onset SLE compared to adult-onset SLE and identified factors associated with cardiac diagnoses.
Methods: We identified children (5-17 years) and adults (18-64 years) with incident SLE (≥3 International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9 CM) code 710.0, > 30 days apart) using Clinformatics® DataMart (OptumInsight, Eden Prairie, MN) deidentified United States administrative claims (2000-2013). We calculated incidence and prevalence of three outcomes: ≥ 1 diagnosis code for (1) pericarditis and/or myocarditis, (2) endocarditis, or (3) valvular insufficiency. Negative binomial regression was used to identify characteristics associated with cardiac diagnoses in children and determine whether SLE onset in childhood vs adulthood was independently associated with cardiac involvement.
Results: There were 297 children and 6927 adults with new-onset SLE. A total of 17.8% of children had ICD-9 CM codes for acute cardiac diagnoses, the incidence of which were highest in the first year after SLE diagnosis (12.2 per 100 person-years). African American race (incidence rate ratio (IRR) 6.6, 95% confidence interval (CI) (2.9, 15.0), p < 0.01) and nephritis (IRR 7.0, 95% CI (2.6, 18.6), p < 0.01) were associated with acute cardiac diagnoses in children. Child-onset disease was independently associated with a 4.4-fold higher rate of pericarditis or myocarditis compared to adult-onset SLE after adjustment for other disease and demographic characteristics (95% CI (2.4, 8.0), p < 0.01).
Conclusion: This study establishes baseline estimates of the incidence and prevalence of pericarditis and myocarditis in child-onset SLE, which is substantially higher than that of adult-onset SLE. Prospective echocardiographic evaluations are needed to validate incidence measures and characterize the natural history of acute cardiac manifestations in child-onset SLE, as well as identify risk factors for poor cardiac outcomes to inform screening and management.
Keywords: Pediatric systemic lupus erythematosus; cardiovascular diseases; systemic lupus erythematosus.