There is a doubled rate of hospitalization for atrial fibrillation in Medicaid recipients with systemic lupus erythematosus (SLE) compared with age- and sex-matched Medicaid recipients without SLE, according to research results published in The Journal of Rheumatology.

Researchers investigated and compared the rates, risks, and risk factors for atrial fibrillation among Medicaid patients with SLE and general age- and sex-matched Medicaid recipients without SLE in a 1:4 ratio. The Medicaid Analytic Extract database was used to evaluate the data of adults aged 18 to 65 years with prevalent SLE who were enrolled in Medicaid between 2007 and 2010.

The SLE cohort included 46,876 patients and the general Medicaid cohort included 187,504 patients; mean age across both cohorts was 41.5±12.2 years, with 93% women. Mean follow-up durations were 1.9±1.1 years and 1.8±1.1 years for the SLE and general Medicaid groups, respectively.

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Over the course of the follow-up period, there were 121 atrial fibrillation hospitalizations (incidence rate, 1.4 per 1000 person-years [PYs]) in the SLE cohort compared with 241 atrial fibrillation hospitalizations in the general Medicaid cohort (incidence rate, 0.7 per 1000 PYs). Atrial fibrillation incidence rates were higher in men and increased with age in both groups; however, after stratifying by age, the incidence rate remained higher in the SLE group vs the general Medicaid group across all age categories.


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Race/ethnicity-adjusted Cox regression models showed that the risk for incident atrial fibrillation hospitalization among patients in the SLE cohort was 1.79-fold higher than the risk in the age- and sex-matched general Medicaid population (95% CI, 1.43-2.24).

Baseline cardiovascular disease, hypertension, lupus nephritis/chronic kidney disease, valvular disease, and Charlson comorbidity index variables changed point estimate by >10% when separately added to the race- and ethnicity-adjusted model.

The strongest hazard ratio attenuation was noted when researchers further adjusted for cardiovascular disease and hypertension. Risk estimates were attenuated and became nonsignificant in a combined model that adjusted for race/ethnicity, cardiovascular disease, and hypertension (hazard ratio, 1.17; 95% CI, 0.92-1.48). According to the researchers, no further adjustment affected risk estimates.

Patients with SLE were stratified by glucocorticoid use; investigators noted a significant increased atrial fibrillation risk in this group either with or without baseline glucocorticoid use.

Study limitations included the short duration of the follow-up and the use of only hospitalization International Statistical Classification of Diseases and Related Health Problems codes, meaning that elevated incidence ratios were “likely underestimates.” Investigators were also unable to assess SLE disease duration because of the nature of administrative data.

“Further work should target modifying risk factors for [atrial fibrillation] identified in this study in an effort to decrease the risk [for atrial fibrillation] among patients with SLE,” the researchers concluded.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Chen SK, Barbhaiya M, Solomon DH, et al. Atrial fibrillation/flutter hospitalizations among U.S. Medicaid recipients with and without systemic lupus erythematosus [published online November 1, 2019]. J Rheumatol. doi:10.3899/jrheum.190502