Abstract
Objective Systemic lupus erythematosus (SLE) is a multi-system chronic inflammatory autoimmune disease with high prevalence of several risk factors for atrial fibrillation/flutter (AF). However, the incidence and risk of AF in SLE have not been well quantified.
Methods We used U.S. Medicaid Analytic eXtract from 2007-2010 to identify beneficiaries ages 18-65, with prevalent SLE, each matched by age and sex to four non-SLE general Medicaid recipients. We estimated the incidence rates (IR) per 1,000 person-years (PY) for AF hospitalizations and used multivariable Cox regression to estimate the hazard ratio (HR) for AF hospitalization.
Results We identified 46,876 U.S. Medicaid recipients with SLE, and 187,504 age- and sex-matched non-SLE controls (93% female; mean age 41.5+12.2). Known AF risk factors such as hypertension, cardiovascular disease (CVD) and kidney disease were more prevalent in SLE patients. During a mean follow-up of 1.9+1.1 years for SLE, and 1.8+1.1 years for controls, the IR per 1,000 PY for AF was 1.4 (95% CI 1.1-1.6) among SLE patients and 0.7 (95% 0.6-0.8) among non-SLE controls. In age- and sex- matched and race-adjusted Cox models, the HR for AF was 1.79 (95%CI 1.43-2.24); after adjustment for baseline hypertension and CVD, the adjusted HR was reduced to 1.17 (95%CI 0.92-1.48).
Conclusion SLE was associated with doubled rate of hospitalization for AF compared to age- and sexmatched general Medicaid patients. In a race-adjusted model, the risk was 80% higher. However, the AF risk factors hypertension and CVD were more prevalent among SLE patients and accounted for the excess risk.
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