Our analysis of 30753 patients admitted to the internal medicine department through the ED revealed an ED-LOS duration exceeding 48 hours in approximately 17% of the patients. Our findings, which suggested that older adults and patients with multiple comorbidities may be at an increased risk of ED-LOS prolongation, were consistent with those of previous research.[12] A previous study has shown that, aside from the complexity of their underlying health conditions, older adults may experience a longer ED-LOS because their symptoms are often non-specific and can result in under-triaging. [13] Besides, patients with lower TTAS levels are more likely to experience prolonged ED-LOS because they are not prioritized for hospital beds allocation due to their relatively low disease acuity.
In 2001, the National Health Service (NHS) in the UK introduced the “four-hour rule” to address inappropriate and prolonged waiting times in the ED. This rule mandated that 98% of ED patients must either be discharged or admitted within a four-hour treatment period.[14] While this initiative reduced mortality rate and ED-LOS, it posed a challenge to physicians in delivering comprehensive patient care. Moreover, it shifted the problem of overcrowding from the EDs to hospital wards.[15, 16] The New Zealand Ministry of Health considers a six-hour target, which provides sufficient time for clinical treatment while minimizing excessive waiting periods, a more appropriate alternative.[17] Setting a reasonable target time for ED-LOS without compromising the quality of emergency care has become a complex challenge, as it varies with each country’s healthcare policies. Most nations establish a cut-off time and a percentile target, defining ED-LOS exceeding the target time as “prolonged ED-LOS.”[1] In our country, the target time for ED-LOS is set at forty-eight hours, serving as a parameter for evaluating ED performance.[18] However, our study findings indicated no significant association between an ED-LOS over forty-eight hours and unfavorable clinical outcomes both in terms of 30-day mortality or hospital-LOS. Our findings were not consistently with those from other studies. For example, Jones et al. reported that a delay of more than five hours in hospital admission from ED arrival was associated with an increased risk of 30-day mortality. [19]
We speculate that several factors may contribute to these findings. First, our designated target time was longer than that in the other studies. Patients in the ED not only wait for an available hospital bed but also receive ongoing treatment during their stay. Although the patient-to-staff ratio and environmental conditions may not be comparable to those in traditional wards or ICUs, a certain level of treatment can be administered to patients in the ED so that the medical conditions of some patients may be effectively managed within 48 hours of treatment.
Furthermore, instead of serving patients on a simple “first-come, first-served” basis, our hospital’s bed allocation system prioritizes patients based on the severity of their illness. Emergency physicians routinely monitor patients’ conditions to ensure prompt admission for those in a more critical condition, resulting in a longer ED-LOS period for relatively stable patients. A prior study has demonstrated a possibly extended ED-LOS period for patients with milder strokes, as priority for admission is often granted to patients with more severe conditions and a higher risk of poor functional outcome.[20]
Despite the common belief of a positive association between the length of ED stay and disease severity, a previous study showed no significant correlation between a prolonged ED-LOS and the clinical outcome of patients with intracerebral hemorrhage.[10] One possible explanation is the lack of effective interventions for ICH that play a critical role in determining the patients’ prognosis rather than the location in which supportive care is given. Therefore, specific diseases need to be taken into account when exploring the relationship between ED-LOS and patients’ outcomes.[21]
To explore the possibility of a distinct impact of ED-LOS on the outcomes of patients diagnosed with specific disease entities, our analysis focused on different divisions of the internal medicine department. Our results demonstrated no significant correlation between a prolonged ED-LOS and an increased mortality rate regardless of the division of the internal medicine department to which the patients were admitted. Patients in the Chest Medicine Division who experienced a prolonged ED-LOS exhibited a reduced mortality rate and shorter hospital-LOS compared to those who were not subjected to a prolonged ED-LOS. This observation may indicate physicians’ accurate assessment of patient respiratory disease severity based on which admission priority was determined. Our finding may also suggest a high flexibility in the length of ED-LOS for patients with less severe respiratory problems. Taken together, our study findings indicated that a prolonged ED-LOS exceeding 48 hours among patients in the Internal Medicine Department may not be linked to adverse outcomes including mortality or hospital-LOS. This underscores the complexity of establishing a suitable target time for ED-LOS which necessitates the consideration of multiple factors.
Further studies are warranted to elucidate the effect of the choice of cut-off timing for ED efficiency evaluation. Moreover, studies focusing on the potential correlation between ED-LOS and the prognosis of patients diagnosed with certain diseases may help identify specific populations who could benefit from expedited hospitalization.
Limitations
While acknowledging the limitations of the study, it is crucial to highlight aditional considerations. Firstly, being a retrospective study, inherent data quality issues are acknowledged and the findings should be interpreted within this context. Secondly, the definition of “prolonged ED-LOS(> 48 hours), while justified, was ultimately arbitary. Consideration of sensitivity analyses to assess the impact of different definitions on the results could enhance the robustness of our findings. Lastly the single-center design call for further validation through large-scale, multi-center studies to enhance the generalizability of our conclusions. Additionally, it is noted that, although ED overcrowding is known to impair the quality of patient care and prolong ED-LOS [22], the specific degree of ED crowding was not accounted for due to the lack of universal concensus on its definition [23, 24]. Subsequent research endeavors should prioritize addressing this important aspect.