Association between the emergency department length of stay in patients requiring hospitalization and in-hospital mortality: a systematic review and meta-analysis.

Abstract

Objective: To assess the association between the emergency department length of stay (EDLOS) and in-hospital mortality through an updated systematic review and meta-analysis.

Methods: A systematic review and meta-analysis was conducted in accordance with the PRISMA 2020 recommendations to identify studies published between January 2022 and December 2025 evaluating the association between EDLOS and in-hospital mortality. The identified studies were combined with those included in a former systematic review covering the period up to January 15, 2022. Searches were conducted across PubMed, MEDLINE, Web of Science, EMBASE, and Cochrane using the same search strategy. Studies including exclusively patients admitted to intensive care units (ICUs) were excluded. Separate meta-analyses were performed for each cutoff used to define prolonged EDLOS, along with an over all meta-analysis including all studies using a cutoff $ 6 hours; when the same study reported several cutoffs, only the longest cutoff was considered.

Results: A total of 6,982 records were identified, and 16 new studies were included (9 suitable for meta-analysis).Together with the 20 studies from the former review (13 included in the meta-analysis), 36 studies were analyzed, 22 of which (9.3 million patients) were included in the quantitative synthesis. No statistically significant association was observed between prolonged EDLOS and in-hospital mortality for any of the cutoffs analyzed: < 4 hours (OR, 0.83; 95% CI, 0.29-2.35), $ 4 hours (OR, 0.82; 95% CI, 0.46-1.46), $ 5 hours (OR, 0.60; 95% CI, 0.21-1.70), $ 6 hours (OR, 0.95; 95% CI, 0.75-1.21), $ 8 hours (OR, 1.10; 95% CI, 0.73-1.65), and $ 24 hours (OR, 0.78; 95% CI, 0.56-1.08). Similarly, the overall meta-analysis showed no association (OR, 1.02; 95% CI, 0.85-1.23). Heterogeneity was high (I² = 80-98%; I² = 97% in the overall analysis), and no relevant publication bias was detected. Studies analyzing EDLOS as a continuous variable suggested increasing mortality with progressively longer stays. Some studies identified associations between prolonged EDLOS and longer hospitalizations, greater resource use, higher hospital costs, specific complications, and a greater need for ICU admission.

Conclusions: The available evidence does not confirm an association between prolonged EDLOS and in-hospital mortality among hospitalized patients. The high degree of heterogeneity limits interpretation of the findings and highlights the need for studies using more homogeneous methodologies and definitions of EDLOS. Moreover, interpretation is limited by the inability to consistently distinguish care time from boarding time across the primary studies.