Prevalence, clinical associations, and outcomes of pericarditis in systemic lupus erythematosus: insights from the University of Toronto Lupus Clinic

Objective Pericarditis is an important clinical feature in the classification criteria and disease activity indices in SLE. We aimed to study the prevalence, associations, and outcomes of pericarditis in SLE. Methods This was an observational cohort study conducted at the University of Toronto Lupus Clinic (July 1970–March 2024). The prevalence of pericarditis was determined in both inception (enrolled within one year of diagnosis) and prevalent cohorts. The outcomes of pericarditis were defined as acute (resolution < 3 months), chronic (lasting ≥ 3 months), and relapsing (recurrence after complete resolution). Associations pericarditis and its outcomes were studied Results Pericarditis was identified in 428 of 2122 patients (20.16%), 205 of 900 (22.8%) in inception, and 223 of 1222 (18.2%) in the prevalent cohort. It developed early in the disease course (median 0.51 years). Among 170 patients, the median chest pain severity was 6.5 of 10. Associated myocarditis was observed in 5.3%, endocarditis in 1.9%, and cardiac tamponade in 1.4%. Pericarditis was associated with younger age at SLE diagnosis [HR 0.98 (95% CI, 0.97–1.00)], higher SLEDAI-2K [1.06 (1.001–1.13)], anti-La antibodies [1.52 (1.01–2.31)], constitutional features [1.98 (1.39, 2.81)] and less skin involvement [0.34 (0.21–0.55)] on multivariable analysis. Most patients (79.5%) had resolution within 3 months. Chronic pericarditis occurred in 15.6% (median 4.6 months) and relapses in 22.9%. No significant associations were found for chronicity or relapse. Conclusion Pericarditis affects 1 in 5 SLE patients, usually early in the disease. Most cases resolve in 3 months, but a subset experiences chronic or relapsing disease.