Effect of holiday admission for acute aortic dissection on in-hospital mortality in Japan: A nationwide study.

BACKGROUND: Patients admitted on weekends have higher mortality than those admitted on weekdays. However, whether the "weekend effect" results in a higher mortality after admission for acute aortic dissection (AAD),-classified according to Stanford types-remains unclear. This study aimed to examine the association between admission day and in-hospital mortality in AAD Type A and B. METHODS: We used data from the Japanese registry of all Cardiac and Vascular Diseases Diagnostic Procedure Combination, a nationwide claim-based database with data from 953 certified hospitals, and enrolled in-patients with AAD admitted between April 1, 2012, and March 31, 2016. Based on the admission day, we stratified patients into groups (Weekdays, Saturdays, and Sundays/holidays). The influence of the admission day on in-hospital mortality was assessed via multi-level logistic regression analysis. We also performed a Stanford type-based stratified analysis. RESULTS: Among the included 25,641 patients, in-hospital mortality was 16.0%. The prevalence of patients admitted with AAD was relatively higher on weekdays. After adjustment for covariates, patients admitted on a Sunday/holiday showed an increased risk of in-hospital mortality (odds ratio [OR] 1.20; 95% confidence interval [CI] 1.07-1.33, p<0.001) than patients admitted on weekdays. Among patients admitted on a Sunday/holiday, only the subgroup of Stanford Type A showed a significantly increased risk of in-hospital mortality. (Stanford Type A, non-surgery vs. surgery groups: 95% CI 1.06-1.48 vs. 1.17-1.68, p<0.001 for both groups, OR 1.25 vs. 1.41, respectively, Stanford Type B, non-surgery vs. surgery groups: 95% CI 0.64-1.09 vs. 0.40-2.10; p = 0.182 vs. 0.846; OR 0.84 vs. 0.92). CONCLUSIONS: In conclusion, patients with AAD Type A admitted on a Sunday/holiday may have an increased in-hospital mortality risk.