Association between Emergency Department Length of Stay and Outcomes among Patients Admitted to Internal Medicine Wards

Objective Although emergency department length of stay (ED-LOS) is an important parameter for assessing ED performance, the relationship between ED-LOS and patient outcomes remains controversial. This study aimed at investigating the possible correlation and exploring the impact of disease nature on patients’ outcomes. Methods From January, 2016 to September, 2022, patients visiting the ED of a tertiary referral hospital and later admitted to the internal medicine wards were retrospectively categorized into two groups: prolonged ED-LOS group (> 48 hours) and reference group (≤ 48 hours). The primary outcomes included hospital-LOS, in-hospital mortality, 30-day mortality since ED visit, and intensive care unit (ICU)-LOS. Results Of a total of 30753 eligible patients, 4554 (14.8%) had prolonged ED-LOS. Factor associated with prolonged ED-LOS included older patients and those with higher Charlson comorbidity index scores (CCIS). In-hospital and 30-day all-cause mortality were 259 (6%) and 296 (7%), respectively, in the prolonged ED-LOS group versus 2021 (8%) and 2066 (8%), respectively, in the reference group. The hospital-LOS and ICU-LOS were 10.8 ± 9.9 and 9.3 ± 7.4 days, respectively, in the prolonged ED-LOS versus 10.9 ± 11.9 and 7.7 ± 8.2 days, respectively, in the reference group. The incidences of adverse outcomes were not different between the two groups. Subgroup analysis based on disease nature demonstrated consistent findings. Conclusion Prolonged ED-LOS (> 48 hours) was not associated with adverse outcomes compared to the reference group. The choice of optimal cut-off timing for assessing ED efficiency and specific patient populations who may benefit from expedited hospitalization remain to be elucidated.