Abstract Body (Do not enter title and authors here):
Background:
Acute myocardial infarction (AMI) is a leading cause of global morbidity and mortality, with prompt percutaneous coronary intervention (PCI) essential to improve outcomes. Resource constraints and reduced staffing on weekends may lead to delayed care and worse outcomes, termed the “weekend effect.” Limited data exist on this effect specifically in AMI patients undergoing PCI.

Research Question: Does weekend admission impact in-hospital outcomes among AMI patients undergoing PCI compared to weekday admission?

Methods: Using the 2018–2020 National Inpatient Sample, we identified adult AMI hospitalizations treated with PCI. Admissions were categorized as weekend (Saturday–Sunday) or weekday (Monday–Friday). Multivariable logistic and linear regression analyses assessed associations with outcomes, adjusting for demographics, comorbidities, socioeconomic factors, and hospital-level characteristics.

Results:
Among 931,555 AMI hospitalizations receiving PCI, 26.7% (n = 249,045) were admitted on weekends. The mean age was 65 years (SD ±13), and 68% were male. The crude in-hospital mortality rates were similar between weekend and weekday admissions (3.4% vs. 3.3%; p = 0.5). However, weekend admissions were associated with significantly longer median stays (3.00 vs. 2.00 days; p < 0.001), higher median charges ($92,098 vs. $89,989; p < 0.001), and a higher proportion of mechanical ventilation use (6.1% vs. 5.7%; p = 0.009). Favorable discharge rates were comparable (88% vs. 88%; p = 0.7).
Multivariate analysis showed weekend admission was not significantly associated with increased mortality (OR 1.05; 95% CI 0.99–1.12; p = 0.082) but was linked to higher odds of mechanical ventilation (OR 1.08; 95% CI 1.03–1.13; p < 0.001) and lower odds of favorable discharge (aOR 0.96; 95% CI 0.92–0.99; p = 0.013). Linear regression further showed that weekend admissions were linked to longer stays (β = 0.21 days; 95% CI 0.16–0.25; p < 0.001) and higher charges (β = $2,159; 95% CI $1,002–$3,317; p < 0.001).

Conclusion:
Weekend admission was not linked to higher mortality but was associated with worse outcomes—more mechanical ventilation, lower favorable discharge, longer stays, and higher costs. These findings highlight the “weekend effect” and the need for consistent, high-quality care throughout the week.