Impact of overnight boarding in the emergency department on in-hospital mortality and length of hospital stay among older patients.

Abstract

Objective: To evaluate the association between overnight boarding in the emergency department after the decision to admit and in-hospital mortality and total episode duration among older patients admitted through the emergency department of a minimally overcrowded hospital in Boston (Massachusetts, United States).

Methods: A retrospective cohort study was conducted using MIMIC-IV data from 2011 through 2019. Patients aged 65 years or older who were admitted through the emergency department and had a documented admission order were included; patients admitted to intensive care were excluded. Overnight boarding was defined as remaining in the emergency department until 8:00 AM, whereas controls were defined as patients who left the emergency department before midnight. Five sensitivity analyses were performed, with adjustment for age, sex, and comorbidity.

Conclusions: In this selected low-risk cohort, overnight boarding was not associated with in-hospital mortality or total episode duration. However, the small number of events and the potential for selection bias preclude ruling out a harmful effect.