Longitudinal trends of systemic lupus erythematous hospitalizations in the United States: a two-decade population-based study

Background Longitudinal data are limited on systemic lupus erythematosus (SLE) hospitalizations. We aim to study longitudinal trends of SLE hospitalizations in the last 2 decades in the United States (U.S). Methods Data were obtained from the National Inpatient Sample database (NIS). We performed a 21-year longitudinal trend analysis of NIS 1998-2018. We searched for hospitalizations for adult patients with a "principal" diagnosis of SLE (SLE flare group) and those with "any" diagnosis of SLE (all SLE hospitalization group) using ICD codes. All non-SLE hospitalizations for adult patients were used as the control. Multivariable logistic and linear regression were used appropriately to calculate adjusted p-trend for the outcomes of interest. Results Incidence of SLE flare hospitalization reduced from 4.1 to 3.2 per 100,000 U.S persons from 1998 to 2018 (adjusted p-trend < 0.0001). The proportion of all hospitalized patients with SLE admitted principally for SLE reduced from 11.3% in 1998 to 5.7% in 2018 (adjusted p-tend < 0.0001). The proportion of hospitalized blacks in the SLE flare and all SLE hospitalization groups increased from 37.7% and 26.9% in 1998 to 44.7% and 30.7% in 2018 respectively (adjusted p-trend < 0.0001). The proportion of hospitalized Hispanics and Asians disproportionally increased in SLE flare hospitalizations compared to the control group. Conclusion The incidence of hospitalization for SLE flare has reduced in the last 2 decades in the U.S. The proportion of hospitalized patients with SLE admitted principally for SLE has reduced significantly over time. However, the burden of SLE hospitalizations among ethnic minorities has increased over time.