Association of Weekend Admission and In-Hospital Mortality in Adult Patients with Acute Myeloid Leukemia in Japan

The effect of weekend admission on patient mortality has been investigated in several therapeutic areas, including acute myeloid leukemia (AML), but the investigations' results are controversial. We evaluated the relationship between in-hospital mortality and weekend admission in adult patients with AML in Japan by conducting a retrospective observational study using administrative data from 144 acute care hospitals from which patients were discharged between April 2014 and March 2019. The primary endpoint was in-hospital mortality, compared between weekend and weekday admissions. Among the 1,340 eligible patients, 11% (150) were admitted during a weekend. The in-hospital mortality rates of the patients admitted during weekends and those admitted on a weekday were 28% (42/150) and 17% (204/1190), respectively. After an adjustment for covariates, weekend admission was associated with a significantly higher risk of in-hospital mortality than weekday admission (HR 1.70, 95%CI: 1.20-2.40; p=0.003). However, such an association was not observed in patients treated in a bio-clean room (HR 1.26, 95%CI: 0.65-2.42). Our results demonstrate that for patients with AML, weekend admission was independently associated with a higher risk of death during hospitalization. An appropriate system is necessary for these patients.