The ‘Weekend Effect’ on Immune Cytopenia: Insights from the National Inpatient Sample Database

Introduction: Outcomes for weekend versus weekday admissions for immune cytopenias including immune thrombocytopenic purpura (ITP), thrombotic thrombocytopenic purpura (TTP), and autoimmune hemolytic anemia (AIHA)/Evan's Syndrome are explored in this abstract.

Methods: A query of the 2012-2019 National Inpatient Sample was performed for primary hospitalizations with immune thrombocytopenic purpura (ITP), thrombotic thrombocytopenic purpura (TTP), and autoimmune hemolytic anemia (AIHA)/Evan's Syndrome using ICD-9/10 codes. Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohorts was generated for each of the ITP, TTP and AIHA/Evan's hospitalization dataset. Variables with standardized mean differences >0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for weekend admission status on outcomes. Significance was set at an alpha level of <0.05. All analysis performed in SPSS versions 26.

Results: 24,325, 2992,and 7,609 hospitalizations were included with 4592, 656, and 1468 weekend admissions in ITP, TTP, and AIHA/Evan's respectively. Propensity matched cohorts were generated adjusting for age, sex, race, median household income and co-morbidities including DM, CHF, CKD/ESRD, and liver disease. The results showed significantly higher, almost two-fold, in-hospital mortality in AIHA for weekend admissions (Odds ratio (OR): 1.85, CI 1.20-2.85, p-value=0.005). In addition, there was significantly higher risk of circulatory shock and mechanical ventilation requirement for weekend admissions in AIHA along with significantly increased length of hospital stay and total hospital charges. TTP patients also showed similar trend towards higher mortality with significantly higher incidence of AKI and increased length of stay for weekend admissions. There was no significant difference seen in ITP. The results are summarized in table 1. These results are partly in agreement with findings of Manadan et al study, which showed lower rate of procedures and higher adjusted mortality for general inpatient admissions in weekends.

Conclusion: Weekend admissions showed poorer outcomes especially in AIHA and TTP. Although the exact reasons are unknown, decreased staffing and procedural availability may be responsible for such findings. Further studies are needed to clarify the steps needed to decrease adverse outcomes for weekend admissions.