The dose-response effect of time between emergency admission and inpatient care on mortality

To analyse mortality associated to emergency admissions on weekends, differentiating whether the patients were admitted to the Internal Medicine department or to the hospital as a whole. Retrospective follow-up study of patients discharged between 2015 and 2019 in: (a) the Internal Medicine department (n = 7656) and (b) the hospital as a whole (n = 83,146). Logistic regression models were fitted to analyse the risk of death, adjusting for age, sex, severity, Charlson index, sepsis, pneumonia, heart failure and day of admission. Cox models were also adjusted for the time from admission until normal inpatient care. There was a significant increase in mortality for patients admitted in weekends with short stays in Internal Medicine (48, 72 and 96 h: OR = 2.50, 1.89 and 1.62, respectively), and hospital-wide (OR = 2.02, 1.41 and 1.13, respectively). The highest risk in weekends occurred on Fridays (stays <= 48 h: OR = 3.92 [95% CI 2.06-7.48]), being no significative on Sundays. The risk increased with the time elapsed from admission until the inpatient department took over care (OR = 5.51 [95% CI 1.42-21.40] when this time reached 4 days). In Cox models patients reached HR = 2.74 (1.00-7.54) when the delay was 4 days. Whether it was Internal Medicine or hospital-wide patients, the risk of death associated with emergency admission in WE increased with the time between admission and transfer of care to the inpatient department; consequently, Friday was the day with the highest risk while Sunday lacked a weekend effect. Healthcare systems should correct this serious problem.