Background/Purpose: SLE patients have increased cardiovascular disease (CVD) risk, including higher risk of stroke, compared to age- and sex-matched diabetes mellitus (DM) patients. Although DM confers high risk of developing atrial fibrillation/flutter (AF), AF prevalence rates, a contributor to stroke, among SLE patients are unknown. We investigated rates and risks of AF hospitalization among SLE patients compared to age- and sex-matched DM and general Medicaid population.

Methods: We used Medicaid Analytic eXtract (MAX) data, containing all billing claims for Medicaid patients from the 29 most populated US states, 2007-2010. We included patients ages 18-65 in three separate cohorts: prevalent SLE, prevalent DM, and a non-SLE, non-DM general Medicaid cohort. We required >3 ICD-9 codes for SLE or DM, each separated by >30 days. Index date was the date of the 3^rd diagnosis code. The general Medicaid cohort was selected by using non-SLE, non-DM ICD-9 codes on the same date as SLE index date. All cohorts required baseline period of 6 months of continuous Medicaid enrollment prior to the index date. Each SLE patient was matched to 2 DM, and 4 non-SLE, non-DM patients by age at index date, and sex. Subjects were followed from index date until death, disenrollment or end of follow-up. We used ICD-9 codes to identify outcomes of AF within primary or secondary hospital discharge diagnoses and calculated rates of first AF hospitalization events per 1,000 person-years. We used Cox regression models to calculate hazard ratios (HR) for first AF hospitalization events. In a secondary analysis, we excluded those with baseline AF.

Results: 40,212 SLE patients were matched to 80,424 DM and 160,848 general Medicaid patients. In all cohorts, 92% were female and mean age was 40.3 (+12.1) years. Mean follow up was 1.8 (+1.1) years for SLE, 1.8 (+1.1) years for DM, and 1.6 (+1.2) years for general Medicaid patients. Baseline CVD was prevalent in 18% SLE, 13% DM and 1% general Medicaid cohorts. Baseline prevalence of AF was 1% in SLE, <1% in DM and <1% in general Medicaid cohorts. Anticoagulant use was present in 7% of SLE vs 2% of DM patients (p<0.001). Beta-blocker use was similar between SLE and DM cohorts (11% in both). AF hospitalization rates per 1,000-person years were similar in SLE vs DM, and nearly double that in the general Medicaid cohort (Table). The adjusted HR for first AF hospitalization was increased among DM (HR 1.9, 95% CI 1.6-2.3) and SLE (HR 1.4, 95% CI 1.1-1.8) patients compared to the general patients, and remained increased after excluding patients with baseline AF.

Conclusion: First AF hospitalization rate among SLE patients was double that of the general non-SLE, non-DM Medicaid population, and similar to the rate among age- and sex-matched DM patients. Adjusted HRs for first AF hospitalization among SLE patients was as high as in DM patients. As DM is a known AF contributor, the similarly elevated risk among SLE patients warrants further investigation.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/atrial-fibrillationflutter-hospitalizations-among-patients-with-sle-and-diabetes-compared-to-the-general-u-s-medicaid-population/