Title: Systemic Lupus Erythematous Readmissions Has Reduced: A 9- Year Longitudinal Study of the Nationwide Readmission Database

Background: Longitudinal data on trends of Systemic Lupus Erythematous (SLE) readmissions is limited. We aim to study trends of 30-day readmissions of patients admitted for SLE flare and all SLE hospitalizations in the United States (U.S) from 2010-2018.Materials and Methods: Data were obtained from the Nationwide Readmission Database (NRD). NRD is the largest nationally representative U.S readmission database. We performed a retrospective 9-year longitudinal trend analysis of NRD 2010–2018 databases. We searched for index hospitalizations for adult patients with diagnosis of SLE using ICD codes. Elective and traumatic readmissions were excluded. The 5 most common readmission reasons for each sampled year were highlighted. Multivariable logistic and linear regression analyses were used to calculate adjusted p-trend for categorical and continuous outcomes, respectively.Results: 30-day readmissions following index admissions of all SLE patients and for SLE flare decreased from 15.6% in 2010 to 13.3% in 2018 (adjusted p-trend<0.0001), and 20.3% in 2010 to 17.6% in 2018 (adjusted p-trend=0.009) respectively. Following SLE flare admissions, hospital length of stay (LOS) reduced from 6.7 to 6 days (adjusted p-trend=0.045), while proportion with Charlson comorbidity index (CCI) score ≥3 increased from 42.2% to 54.4% (adjusted p-trend<0.0001) during the study period. SLE and its organ involvement, sepsis, and infections were common reasons for 30-day readmissions. Conclusion: About 1 in 5 SLE flare admission results in 30-day readmission. 30-day readmissions following index hospitalization for SLE flares and all SLE hospitalizations have reduced in the last decade. Although readmission LOS reduced, CCI score has increased over time.