Atrial Fibrillation/flutter Hospitalizations among US Medicaid Recipients with and without Systemic Lupus...

Systemic lupus erythematosus (SLE) is a multisystem 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.

We used the United States Medicaid Analytic eXtract from 2007 to 2010 to identify beneficiaries aged 18-65 years, with prevalent SLE, each matched by age and sex to 4 non-SLE general Medicaid recipients. We estimated the incidence rates (IR) per 1000 person-years (PY) for AF hospitalizations and used multivariable Cox regression to estimate the HR for AF hospitalization.

We identified 46,876 US Medicaid recipients with SLE, and 187,504 age- and sex-matched non-SLE controls (93% female; mean age 41.5 ± 12.2 yrs). Known AF risk factors such as hypertension (HTN), cardiovascular disease (CVD), and kidney disease were more prevalent in patients with SLE. During a mean followup of 1.9 ± 1.1 years for SLE, and 1.8 ± 1.1 years for controls, the IR per 1000 PY for AF was 1.4 (95% CI 1.1-1.6) among patients with SLE and 0.7 (95% CI 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 HTN and CVD, the adjusted HR was reduced to 1.17 (95% CI 0.92-1.48).

SLE was associated with a doubled rate of hospitalization for AF compared to age- and sex-matched general Medicaid patients. In a race-adjusted model, the risk was 80% higher. However, the AF risk factors HTN and CVD were more prevalent among patients with SLE and accounted for the excess risk.