Weekend Hospital Admission and Outcomes Following Emergency Cholecystectomy: A National Analysis of 194,787 Admissions, 2018–2022

Background: Acute cholecystitis affects approximately 200,000 hospitalizations annually in the United States, and emergency cholecystectomy is its definitive treatment. Whether weekend hospital admission, which is often associated with reduced staffing and diagnostic resources, adversely affects surgical outcomes in this population is unclear. We evaluated the association between weekend hospital admission and in-hospital mortality and key secondary outcomes following emergency cholecystectomy. Methods: This retrospective cohort study used the National Inpatient Sample (NIS) from January 2018 through December 2022. Adults (≥18 years) with acute cholecystitis (identified by ICD-10-CM codes) who underwent nonelective cholecystectomy (identified by ICD-10-PCS codes) were included; elective admissions, pediatric patients, and admissions with missing discharge weights were excluded. The analytic cohort comprised 194,787 unweighted admissions, representing a weighted national estimate of approximately 973,935 hospitalizations. Weekend admission was defined as admission on Saturday or Sunday (vs. Monday through Friday). The primary outcome was in-hospital mortality. Secondary outcomes, defined from secondary (not principal) diagnosis fields and interpreted as coded in-hospital diagnoses, included prolonged length of stay (>75th percentile), sepsis, surgical site infection, bile duct injury, venous thromboembolism, respiratory failure, acute kidney injury, blood transfusion, and cardiac complications. Multivariable logistic regression with hospital-year cluster-robust standard errors was used, adjusting for pre-exposure patient and hospital characteristics; the Benjamini–Hochberg false discovery rate was applied across secondary outcomes. Results: Among 194,787 admissions (weekday, 73.2%; weekend, 26.8%), in-hospital mortality was 0.62% in weekday and 0.53% in weekend patients. After adjustment, weekend admission was not associated with in-hospital mortality (aOR 0.87; 95% CI, 0.75–1.00; p = 0.06). Weekend admission was associated with modestly lower odds of prolonged length of stay (aOR 0.90; 95% CI, 0.88–0.93; p < 0.001). Weekend admission was not associated with sepsis (5.3% vs. 5.3%; aOR 1.01; 95% CI, 0.96–1.06; p = 0.65), respiratory failure (aOR 1.05; 95% CI, 1.00–1.10; p = 0.06), overall complications, or the remaining secondary outcomes after correction for multiple comparisons. Findings were consistent across design-based survey-weighted, inverse-probability-weighted, transfer-excluded, and principal-diagnosis sensitivity analyses. Conclusions: Weekend admission was not associated with higher in-hospital mortality or with a higher risk of sepsis following emergency cholecystectomy in the United States; weekend patients had modestly shorter hospital stays. These findings provide no evidence of higher coded in-hospital mortality or coded in-hospital complications among weekend admissions in contemporary US practice.