Abstract Body: Introduction:
A ruptured aortic aneurysm (RAA) is a critical condition with significant morbidity and mortality. Previous analyses have demonstrated an increase in mortality for patients admitted with RAA on weekends. This analysis will compare these findings with the 2021 data to determine if the "weekend effect" persists.

Methods:
Of the 33.3 million hospital discharges in the US in 2021, 30.6 million non-elective admissions for patients aged 18 and older were included. A total of 5,865 patients with RAA were analyzed. Statistical comparisons employed chi-square and t-tests. Multivariable logistic regression calculated adjusted odds ratios (ORs) for in-hospital mortality, accounting for age, sex, race, socioeconomic status, comorbidities, hospital region, teaching status, and bed size.

Results:
Of the 5,865 patients with RAAs, 4,010 (68.4%) had primary diagnoses and 1,930 (32.9%) had secondary diagnoses. Admissions occurred predominantly on weekdays (70.8%), with 29.2% occurring on weekends. Gender distribution was similar across both groups (weekday: 67.0% male, weekend: 69.9% male; p = 0.336). Weekend admissions were younger (72.5 vs. 73.8 years, p = 0.088). Racial distribution (77.3% White, 10.3% Black, 5.9% Hispanic) and primary payer categories (75.8% Medicare, 15.0% private insurance, 6.5% Medicaid) also showed no significant differences between groups (p > 0.05).

Interventions (open or percutaneous) was performed in 60.6% of cases, with no significant difference in rates between weekdays (61.7%) and weekends (57.9%) (p = 0.2213). Similarly, no significant differences were observed in hospital characteristics, including region, teaching status, and bed size (p > 0.15). Overall, 31.2% of patients died during hospitalization, with 30.2% mortality in primary diagnoses and 33.9% in secondary diagnoses.

Multivariable logistic regression analysis revealed that weekend admissions were not significantly associated with increased mortality (adjusted OR 1.15, 95% CI: 0.87–1.51, p = 0.33). However, age was a significant predictor of mortality, with an adjusted OR of 1.03 per year (95% CI: 1.02–1.05, p < 0.001).

Conclusion:
This nationwide analysis demonstrates no significant difference in in-hospital mortality between weekday and weekend admissions for RAA. While previous studies highlighted a "weekend effect" with increased mortality for RAA admissions on weekends, our findings suggest that this disparity is diminishing.