Background/Purpose: Cardiovascular disease (CVD) risk is elevated in SLE patients compared to non-SLE patients.  However, how CVD rates differ in SLE patients compared with other chronic disease states, in particular diabetes mellitus (DM), has not been examined. To provide insights for clinicians seeking to understand the magnitude of CVD risk in SLE patients, we compared their risk to that of patients with DM, a known CVD risk factor. We examined annual rates and relative risks of CVD events (acute myocardial infarction [MI], stroke, and combined MI or stroke) in a nationwide cohort of US Medicaid recipients with either SLE or DM.

Methods : We utilized Medicaid Analytic eXtract (MAX) data, containing billing claims for Medicaid patients from the 29 most populated US states, 2007-10. We identified adults aged ≥18-65 with prevalent SLE or DM (≥3 ICD-9 codes for SLE or DM, each separated by ≥30 days) and >6 months of enrollment prior to 3rd code (index date). We performed 1: 2 matching (SLE: DM) based on age (month/year), sex, and index date. Sociodemographic data (including age, sex, race/ethnicity, calendar year, US region, zip code-level socioeconomic status) and medical/cardiac comorbidities were collected during the baseline period (6 months prior to and including index date). ICD-9, CPT, and DRG codes were used to identify outcomes. Outcomes were assessed from index date, including acute MI, stroke, and combined MI or stroke. Subjects were followed to first CVD event, death, Medicaid disenrollment, or end of follow-up. We used Cox sub-distribution regression models to calculate hazard ratios (HR_SD) for CVD events, accounting for the competing risk of death and adjusting for sociodemographics and medical/cardiac comorbidities (Table).

Results : 32,089 prevalent SLE patients were matched to 64,178 prevalent DM patients. In both cohorts, 92.8% were female and mean age was 41.3 (±12.1) years. There were more Blacks (41.1 vs. 30.5%) and fewer Whites (36.3 vs 45.1%) in the SLE vs. DM cohort. Mean follow-up was 1.67 (±1.03) years for SLE patients and 1.79 (±1.07) years for DM patients. Baseline CVD risk factors were more prevalent among DM vs. SLE patients: hypertension (38.0 vs. 33.7%), hyperlipidemia (22.5 vs. 10.6%), and obesity (11 vs. 4.5%). In the SLE cohort in particular, the incidence of stroke was higher than that of MI (Table).  Annual rates and adjusted risks of MI were similar in the two cohorts (multivariable-adjusted HR_SD 1.01 [95% CI 0.84-1.22] for SLE vs. DM). By contrast, stroke rates were higher among SLE vs. DM patients and the multivariable-adjusted HR_SD for stroke was 1.38 (95%CI 1.20-1.60). 

Conclusion : Despite a lower prevalence of many traditional CVD risk factors compared to age- and sex-matched DM patients, SLE patients had similar adjusted risks of MI and 38% higher adjusted risks of stroke. These findings may signal potential additional SLE-specific and thrombotic risk factors associated with elevated risk of stroke among SLE patients.